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Messaoudi Y, Smichi N, Allaf T, Besombes C, Allaf K, Gargouri M. Instant Controlled Pressure-Drop (DIC) for Volatile Compound Extraction and Bioethanol Production from Empty Aleppo Pinecones and Eucalyptus Chips: Process Optimization and Statistical Modeling. Appl Biochem Biotechnol 2023; 195:7086-7109. [PMID: 36988842 DOI: 10.1007/s12010-023-04437-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2023] [Indexed: 03/30/2023]
Abstract
Several plant species contain volatile compounds extracted as "essential oils" through different technologies. After essential oil extraction, the residual solid is a lignocellulosic solid waste. This work proposes the instant controlled pressure-drop (DIC) technology to autovaporize volatile compounds and modify the lignocellulosic matrix. Indeed, DIC technology is a thermomechanical process based on short-time/high-temperature and pressure pretreatment. It enhances the saccharification and fermentation process (SSF) for bioethanol production. A 3-variable design of experiments optimized the DIC processing parameters to reach 100% efficiency (EE) of volatile compound extraction using response surface methodology (RSM). Eucalyptus chips presented 50 volatile identified compounds after 7 min of DIC treatment. 1,8-Cineole, β-phellandrene, aromadendrene, eudesmol, and spathulenol are the most important volatile compounds. The empty Aleppo pinecones delivered 32 volatile compounds in 5 min of DIC treatment, the most important of which were caryophyllene, nortricyclene, verbenol, and camphor. After the autovaporization extraction stage, solid fraction residues were hydrolyzed and fermented in the same stirred bioreactor, using SSF strategy for 72 h at 37 °C. The highest bioethanol yields reached 73.9% and 54.82% (g per 100 g DM) from eucalyptus chip and empty Aleppo pinecone, respectively.
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Affiliation(s)
- Yosra Messaoudi
- Biocatalysis and Industrial Enzymes Group, Laboratory of Microbial Ecology and Technology, Carthage University, National Institute of Applied Sciences and Technology, BP 676, 1080, Tunis Cedex, Tunis, Tunisia.
| | - Neila Smichi
- Biocatalysis and Industrial Enzymes Group, Laboratory of Microbial Ecology and Technology, Carthage University, National Institute of Applied Sciences and Technology, BP 676, 1080, Tunis Cedex, Tunis, Tunisia
| | | | - Colette Besombes
- Laboratory of Engineering Science and Technology for Environment (LaSIE), La Rochelle University, 17042, La Rochelle, France
| | - Karim Allaf
- Laboratory of Engineering Science and Technology for Environment (LaSIE), La Rochelle University, 17042, La Rochelle, France
| | - Mohamed Gargouri
- Biocatalysis and Industrial Enzymes Group, Laboratory of Microbial Ecology and Technology, Carthage University, National Institute of Applied Sciences and Technology, BP 676, 1080, Tunis Cedex, Tunis, Tunisia
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Effect of Laccase Detoxification on Bioethanol Production from Liquid Fraction of Steam-Pretreated Olive Tree Pruning. FERMENTATION-BASEL 2023. [DOI: 10.3390/fermentation9030214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
During lignocellulosic bioethanol production, the whole slurry obtained by steam explosion is filtered, generating a water-insoluble fraction rich in cellulose which is used for saccharification and ethanol fermentation, as well as a liquid fraction containing solubilised glucose and xylose but also some inhibitory by-products (furan derivatives, weak acids and phenols), which limits its use for this purpose. Since utilization of this liquid fraction to ethanol is essential for an economically feasible cellulosic ethanol process, this work studied a laccase from Myceliophthora thermophila to detoxify the liquid fraction obtained from steam-pretreated olive tree pruning (OTP) and to overcome the effects of these inhibitors. Then, the fermentation of laccase-treated liquid fraction was evaluated on ethanol production by different Saccharomyces cerevisiae strains, including the Ethanol Red, with the capacity to ferment glucose but not xylose, and the xylose-fermenting recombinant strain F12. Laccase treatment reduced total phenols content by 87% from OTP liquid fraction, not affecting furan derivatives and weak acids concentration. Consequently, the fermentative behavior of both Ethanol Red and F12 strains was improved, and ethanol production and yields were increased. Moreover, F12 strain was capable of utilizing some xylose, which increased ethanol production (10.1 g/L) compared to Ethanol Red strain (8.6 g/L).
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Poveda-Giraldo JA, Garcia-Vallejo MC, Cardona Alzate CA. Analysis of Single-Step Pretreatments for Lignocellulosic Platform Isolation as the Basis of Biorefinery Design. Molecules 2023; 28:molecules28031278. [PMID: 36770944 PMCID: PMC9921018 DOI: 10.3390/molecules28031278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/19/2023] [Accepted: 01/26/2023] [Indexed: 02/03/2023] Open
Abstract
Biorefinery feasibility is highly influenced by the early design of the best feedstock transformation pathway to obtain value-added products. Pretreatment has been identified as the critical stage in biorefinery design since proper pretreatment influences subsequent reaction, separation, and purification processes. However, many pretreatment analyses have focused on preserving and valorizing six-carbon sugars for future use in bioconversion processes, leaving aside fractions such as hemicellulose and lignin. To date, there has been no pretreatment systematization for the removal of lignocellulosic fractions. This work defines pretreatment efficacy through operational, economic, environmental, and social indicators. Thus, using the data reported in the literature, as well as the results of the simulation schemes, a multi-criteria weighting of the best-performing schemes for the isolation or removal of cellulose, hemicellulose, and lignin was carried out. As a main result, it was concluded that dilute acid is the most effective for cellulose isolation and hemicellulose removal for producing platform products based on six- and five-carbon sugars, respectively. Additionally, the kraft process is the best methodology for lignin removal and its future use in biorefineries. The results of this work help to elucidate a methodological systematization of the pretreatment efficacy in the design of biorefineries as an early feasibility stage considering sustainability aspects.
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Homo- and heterofermentative lactobacilli are distinctly affected by furanic compounds. Biotechnol Lett 2022; 44:1431-1445. [DOI: 10.1007/s10529-022-03310-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/24/2022] [Accepted: 10/05/2022] [Indexed: 11/07/2022]
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Cheng Z, Luo X, Zhu Z, Huang Y, Yan X. Furfural Produces Dose-Dependent Attenuating Effects on Ethanol-Induced Toxicity in the Liver. Front Pharmacol 2022; 13:906933. [PMID: 35754511 PMCID: PMC9214037 DOI: 10.3389/fphar.2022.906933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/12/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Alcohol-associated liver disease (ALD) increases the health burden worldwide, but effective drugs to prevent ALD are lacking. Furfural is a small molecule that can limit alcohol production in microorganisms and may have the capacity to attenuate ethanol-induced toxicity. Methods: Human HepG2 cells were incubated with ethanol and furfural, and cell viability, NAD+/NADH ratio, and mitochondrial function assays were performed. RNA sequencing (RNA-seq) data were used to annotate enriched pathways, and these findings were confirmed by reverse transcription-quantitative PCR (RT–qPCR) and Western blotting. C57BL/6J mice were fed a Lieber-DeCarli liquid diet. After 4 weeks, biochemical analysis of mouse serum and histological analysis of mouse livers were performed. Results: Different concentrations of furfural exerted different effects on mitochondria: low-dose furfural reduced reactive oxygen species (ROS) production, maintained mitochondrial transmembrane potential, and inhibited apoptosis pathway activation, while high-dose furfural led to the opposite effects. In mice, furfural mitigated transaminase increases and attenuated the lipid metabolism disorder that had been induced by ethanol. Conclusion: Low-dose furfural reduced ethanol-induced toxicity in the liver. Consuming food or beverages containing the appropriate level of furfural when drinking alcohol may be a convenient and useful way to prevent ALD.
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Affiliation(s)
- Zhuo Cheng
- The Department of Gastroenterology and Hepatology, Peking University Third Hospital, Beijing, China
| | - Xuanmei Luo
- National Center of Gerontology, Beijing Hospital, Beijing, China
| | - Zixin Zhu
- Department of Infectious Diseases, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Yonghui Huang
- The Department of Gastroenterology and Hepatology, Peking University Third Hospital, Beijing, China
| | - Xiue Yan
- The Department of Gastroenterology and Hepatology, Peking University Third Hospital, Beijing, China
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6
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Cagnin L, Gronchi N, Basaglia M, Favaro L, Casella S. Selection of Superior Yeast Strains for the Fermentation of Lignocellulosic Steam-Exploded Residues. Front Microbiol 2021; 12:756032. [PMID: 34803979 PMCID: PMC8601721 DOI: 10.3389/fmicb.2021.756032] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022] Open
Abstract
The production of lignocellulosic ethanol calls for a robust fermentative yeast able to tolerate a wide range of toxic molecules that occur in the pre-treated lignocellulose. The concentration of inhibitors varies according to the composition of the lignocellulosic material and the harshness of the pre-treatment used. It follows that the versatility of the yeast should be considered when selecting a robust strain. This work aimed at the validation of seven natural Saccharomyces cerevisiae strains, previously selected for their industrial fitness, for their application in the production of lignocellulosic bioethanol. Their inhibitor resistance and fermentative performances were compared to those of the benchmark industrial yeast S. cerevisiae Ethanol Red, currently utilized in the second-generation ethanol plants. The yeast strains were characterized for their tolerance using a synthetic inhibitor mixture formulated with increasing concentrations of weak acids and furans, as well as steam-exploded lignocellulosic pre-hydrolysates, generally containing the same inhibitors. The eight non-diluted liquors have been adopted to assess yeast ability to withstand bioethanol industrial conditions. The most tolerant S. cerevisiae Fm17 strain, together with the reference Ethanol Red, was evaluated for fermentative performances in two pre-hydrolysates obtained from cardoon and common reed, chosen for their large inhibitor concentrations. S. cerevisiae Fm17 outperformed the industrial strain Ethanol Red, producing up to 18 and 39 g/L ethanol from cardoon and common reed, respectively, with ethanol yields always higher than those of the benchmark strain. This natural strain exhibits great potential to be used as superior yeast in the lignocellulosic ethanol plants.
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Affiliation(s)
- Lorenzo Cagnin
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
| | - Nicoletta Gronchi
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
| | - Marina Basaglia
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
| | - Lorenzo Favaro
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
| | - Sergio Casella
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
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7
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Production of Furfural-Diethyl-Acetal as Biofuel Additives for Gasoline by Metal Free Porphyrin Photocatalyst Under Visible Light. Catal Letters 2021. [DOI: 10.1007/s10562-021-03809-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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Vanmarcke G, Deparis Q, Vanthienen W, Peetermans A, Foulquié-Moreno MR, Thevelein JM. A novel AST2 mutation generated upon whole-genome transformation of Saccharomyces cerevisiae confers high tolerance to 5-Hydroxymethylfurfural (HMF) and other inhibitors. PLoS Genet 2021; 17:e1009826. [PMID: 34624020 PMCID: PMC8500407 DOI: 10.1371/journal.pgen.1009826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/14/2021] [Indexed: 11/19/2022] Open
Abstract
Development of cell factories for conversion of lignocellulosic biomass hydrolysates into biofuels or bio-based chemicals faces major challenges, including the presence of inhibitory chemicals derived from biomass hydrolysis or pretreatment. Extensive screening of 2526 Saccharomyces cerevisiae strains and 17 non-conventional yeast species identified a Candida glabrata strain as the most 5-hydroxymethylfurfural (HMF) tolerant. Whole-genome (WG) transformation of the second-generation industrial S. cerevisiae strain MD4 with genomic DNA from C. glabrata, but not from non-tolerant strains, allowed selection of stable transformants in the presence of HMF. Transformant GVM0 showed the highest HMF tolerance for growth on plates and in small-scale fermentations. Comparison of the WG sequence of MD4 and GVM1, a diploid segregant of GVM0 with similarly high HMF tolerance, surprisingly revealed only nine non-synonymous SNPs, of which none were present in the C. glabrata genome. Reciprocal hemizygosity analysis in diploid strain GVM1 revealed AST2N406I as the only causative mutation. This novel SNP improved tolerance to HMF, furfural and other inhibitors, when introduced in different yeast genetic backgrounds and both in synthetic media and lignocellulose hydrolysates. It stimulated disappearance of HMF and furfural from the medium and enhanced in vitro furfural NADH-dependent reducing activity. The corresponding mutation present in AST1 (i.e. AST1D405I) the paralog gene of AST2, also improved inhibitor tolerance but only in combination with AST2N406I and in presence of high inhibitor concentrations. Our work provides a powerful genetic tool to improve yeast inhibitor tolerance in lignocellulosic biomass hydrolysates and other inhibitor-rich industrial media, and it has revealed for the first time a clear function for Ast2 and Ast1 in inhibitor tolerance.
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Affiliation(s)
- Gert Vanmarcke
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Quinten Deparis
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Ward Vanthienen
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Arne Peetermans
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Maria R. Foulquié-Moreno
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Johan M. Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
- NovelYeast bv, Open Bio-Incubator, Erasmus High School, Brussels (Jette), Belgium
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9
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Carvalho LM, Carvalho-Netto OV, Calderón LL, Gutierrez M, de Assis MA, Mofatto LS, Camargo AP, Dos Santos LV, Borelli G, Temer B, Araujo G, Pereira GAG, Carazzolle MF. Understanding the differences in 2G ethanol fermentative scales through omics data integration. FEMS Yeast Res 2021; 21:6275189. [PMID: 33983370 DOI: 10.1093/femsyr/foab030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/11/2021] [Indexed: 01/04/2023] Open
Abstract
In this work, we evaluated the fermentative performance and metabolism modifications of a second generation (2G) industrial yeast by comparing an industrial condition during laboratory and industrial scale fermentations. Fermentations were done using industrial lignocellulosic hydrolysate and a synthetic medium containing inhibitors and analyses were carried out through transcriptomics and proteomics of these experimental conditions. We found that fermentation profiles were very similar, but there was an increase in xylose consumption rate during fermentations using synthetic medium when compared to lignocellulosic hydrolysate, likely due to the presence of unknown growth inhibitors contained in the hydrolysate. We also evaluated the bacterial community composition of the industrial fermentation setting and found that the presence of homofermentative and heterofermentative bacteria did not significantly change the performance of yeast fermentation. In parallel, temporal differentially expressed genes (tDEG) showed differences in gene expression profiles between compared conditions, including heat shocks and the presence of up-regulated genes from the TCA cycle during anaerobic xylose fermentation. Thus, we indicate HMF as a possible electron acceptor in this rapid respiratory process performed by yeast, in addition to demonstrating the importance of culture medium for the performance of yeast within industrial fermentation processes, highlighting the uniquenesses according to scales.
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Affiliation(s)
- Lucas M Carvalho
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil.,Center for Computing in Engineering and Sciences, UNICAMP, Campinas, São Paulo 13083-861, Brazil
| | - Osmar V Carvalho-Netto
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Luige L Calderón
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Milena Gutierrez
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Michelle A de Assis
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Luciana S Mofatto
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Antonio P Camargo
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Leandro V Dos Santos
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil.,Brazilian Biorenewable National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), St. Giuseppe Máximo Scolfaro, 10000 - Bosque das Palmeiras, Campinas, São Paulo 13083-100, Brazil
| | - Guilherme Borelli
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Beatriz Temer
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Guido Araujo
- Center for Computing in Engineering and Sciences, UNICAMP, Campinas, São Paulo 13083-861, Brazil.,Institute of Computing, UNICAMP, Campinas, São Paulo 13083-852, Brazil
| | - Gonçalo A G Pereira
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Marcelo F Carazzolle
- Department of Genetics, Evolution, Microbiology, and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil.,Center for Computing in Engineering and Sciences, UNICAMP, Campinas, São Paulo 13083-861, Brazil
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10
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Liu ZL. Reasons for 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde resistance in Saccharomyces cerevisiae: current state of knowledge and perspectives for further improvements. Appl Microbiol Biotechnol 2021; 105:2991-3007. [PMID: 33830300 DOI: 10.1007/s00253-021-11256-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/16/2021] [Accepted: 03/23/2021] [Indexed: 11/25/2022]
Abstract
Common toxic compounds 2-furaldehyde (furfural) and 5-hydroxymethyl-2-furaldehyde (HMF) are formed from dehydration of pentose and hexose, respectively, during decomposition of lignocellulosic biomass polymers. Furfural and HMF represent a major class of aldehyde toxic chemicals that inhibit microbial growth and interfere with subsequent fermentation for production of renewable fuels and chemicals. Understanding mechanisms of yeast tolerance aids development of tolerant strains as the most economic means to overcome the toxicity. This review updates current knowledge on yeast resistance to these toxic chemicals obtained from rapid advances in the past few years. Findings are largely exemplified by an adapted strain NRRL Y-50049 compared with its progenitor, the industrial yeast Saccharomyces cerevisiae type strain NRRL Y-12632. Newly characterized molecular phenotypes distinguished acquired resistant components of Y-50049 from innate stress response of its progenitor Y-12632. These findings also raised important questions on how to address more deeply ingrained changes in addition to local renovations for yeast adaptation. An early review on understandings of yeast tolerance to these inhibitory compounds is available and its contents omitted here to avoid redundancy. Controversial and confusing issues on identification of yeast resistance to furfural and HMF are further clarified aiming improved future research. Propositions and perspectives on research understanding molecular mechanisms of yeast resistance and future improvements are also presented. KEY POINTS: • Distinguished adapted resistance from innate stress response in yeast. • Defined pathway-based molecular phenotypes of yeast resistance. • Proposed genomic insight and perspectives on yeast resistance and adaptation.
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Affiliation(s)
- Z Lewis Liu
- National Center for Agricultural Utilization Research, Bioenergy Research Unit, USDA Agricultural Research Service, 1815 N. University Street, Peoria, IL, 61604, USA.
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11
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Wu Y, Ge S, Xia C, Cai L, Mei C, Sonne C, Park YK, Kim YM, Chen WH, Chang JS, Lam SS. Using low carbon footprint high-pressure carbon dioxide in bioconversion of aspen branch waste for sustainable bioethanol production. BIORESOURCE TECHNOLOGY 2020; 313:123675. [PMID: 32563796 DOI: 10.1016/j.biortech.2020.123675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/09/2020] [Accepted: 06/09/2020] [Indexed: 06/11/2023]
Abstract
An innovative approach was developed by incorporating high-pressure CO2 into the separate hydrolysis-fermentation of aspen leftover branches, aiming to enhance the bioethanol production efficiency. The high-pressure CO2 significantly increased the 72-h enzymatic hydrolysis yield of converting aspen into glucose from 53.8% to 82.9%. The hydrolysis process was performed with low enzyme loading (10 FPU g-1 glucan) with the aim of reducing the cost of fuel bioethanol production. The ethanol yield from fermentation of the hydrolyzed glucose using yeast (Saccharomyces cerevisiae) was 8.7 g L-1, showing increment of 10% compared with the glucose control. Techno-economic analysis indicated that the energy consumption of fuel bioethanol production from aspen branch chips was reduced by 35% and the production cost was cut 44% to 0.615 USD L-1, when 68 atm CO2 was introduced into the process. These results furtherly emphasized the low carbon footprint of this sustainable energy production approach.
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Affiliation(s)
- Yingji Wu
- Co-Innovation Center of Efficient Processing and Utilization of Forestry Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Shengbo Ge
- Co-Innovation Center of Efficient Processing and Utilization of Forestry Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Changlei Xia
- Co-Innovation Center of Efficient Processing and Utilization of Forestry Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China; Anhui Juke Graphene Technology Co., Ltd., Bozhou, Anhui 233600, China
| | - Liping Cai
- Co-Innovation Center of Efficient Processing and Utilization of Forestry Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Changtong Mei
- Co-Innovation Center of Efficient Processing and Utilization of Forestry Resources, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Christian Sonne
- Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark
| | - Young-Kwon Park
- School of Environmental Engineering, University of Seoul, Seoul 02504, Republic of Korea
| | - Young-Min Kim
- Department of Environmental Engineering, Daegu University, Gyeongsan 38453, Republic of Korea
| | - Wei-Hsin Chen
- Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan; Department of Chemical and Materials Engineering, College of Engineering, Tunghai University, Taichung 407, Taiwan; Department of Mechanical Engineering, National Chin-Yi University of Technology, Taichung 411, Taiwan
| | - Jo-Shu Chang
- Department of Chemical and Materials Engineering, College of Engineering, Tunghai University, Taichung 407, Taiwan; Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Su Shiung Lam
- Pyrolysis Technology Research Group, Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; Henan Province Engineering Research Center for Biomass Value-Added Products, Henan Agricultural University, Zhengzhou, Henan 450002, China; Anhui Juke Graphene Technology Co., Ltd., Bozhou, Anhui 233600, China.
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12
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Differential effects of major inhibitory compounds from sugarcane-based lignocellulosic hydrolysates on the physiology of yeast strains and lactic acid bacteria. Biotechnol Lett 2020; 42:571-582. [DOI: 10.1007/s10529-020-02803-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 01/13/2020] [Indexed: 12/24/2022]
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13
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Cunha JT, Soares PO, Romaní A, Thevelein JM, Domingues L. Xylose fermentation efficiency of industrial Saccharomyces cerevisiae yeast with separate or combined xylose reductase/xylitol dehydrogenase and xylose isomerase pathways. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:20. [PMID: 30705706 PMCID: PMC6348659 DOI: 10.1186/s13068-019-1360-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 01/18/2019] [Indexed: 05/12/2023]
Abstract
BACKGROUND Xylose isomerase (XI) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways have been extensively used to confer xylose assimilation capacity to Saccharomyces cerevisiae and tackle one of the major bottlenecks in the attainment of economically viable lignocellulosic ethanol production. Nevertheless, there is a lack of studies comparing the efficiency of those pathways both separately and combined. In this work, the XI and/or XR/XDH pathways were introduced into two robust industrial S. cerevisiae strains, evaluated in synthetic media and corn cob hemicellulosic hydrolysate and the results were correlated with the differential enzyme activities found in the xylose-pathway engineered strains. RESULTS The sole expression of XI was found to increase the fermentative capacity of both strains in synthetic media at 30 °C and 40 °C: decreasing xylitol accumulation and improving xylose consumption and ethanol production. Similar results were observed in fermentations of detoxified hydrolysate. However, in the presence of lignocellulosic-derived inhibitors, a positive synergistic effect resulted from the expression of both XI and XR/XDH, possibly caused by a cofactor equilibrium between the XDH and furan detoxifying enzymes, increasing the ethanol yield by more than 38%. CONCLUSIONS This study clearly shows an advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose. Furthermore, and for the first time, the simultaneous utilization of XR/XDH and XI pathways was compared to the single expression of XR/XDH or XI and was found to improve ethanol production from non-detoxified hemicellulosic hydrolysates. These results extend the knowledge regarding S. cerevisiae xylose assimilation metabolism and pave the way for the construction of more efficient strains for use in lignocellulosic industrial processes.
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Affiliation(s)
- Joana T. Cunha
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Pedro O. Soares
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Aloia Romaní
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Johan M. Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Flanders Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Flanders Belgium
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
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Liu ZL. Understanding the tolerance of the industrial yeast Saccharomyces cerevisiae against a major class of toxic aldehyde compounds. Appl Microbiol Biotechnol 2018; 102:5369-5390. [PMID: 29725719 DOI: 10.1007/s00253-018-8993-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 12/27/2022]
Abstract
Development of the next-generation biocatalyst is vital for fermentation-based industrial applications and a sustainable bio-based economy. Overcoming the major class of toxic compounds associated with lignocellulose-to-biofuels conversion is one of the significant challenges for new strain development. A significant number of investigations have been made to understand mechanisms of the tolerance for industrial yeast. It is humbling to learn how complicated the cell's response to the toxic chemicals is and how little we have known about yeast tolerance in the universe of the living cell. This study updates our current knowledge on the tolerance of industrial yeast against aldehyde inhibitory compounds at cellular, molecular and the genomic levels. It is comprehensive yet specific based on reproducible evidence and cross confirmed findings from different investigations using varied experimental approaches. This research approaches a rational foundation toward a more comprehensive understanding on the yeast tolerance. Discussions and perspectives are also proposed for continued exploring the puzzle of the yeast tolerance to aid the next-generation biocatalyst development.
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Affiliation(s)
- ZongLin Lewis Liu
- The US Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Bioenergy Research Unit, 1815 N University Street, Peoria, IL, 61604, USA.
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15
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Wu G, Xu Z, Jönsson LJ. Profiling of Saccharomyces cerevisiae transcription factors for engineering the resistance of yeast to lignocellulose-derived inhibitors in biomass conversion. Microb Cell Fact 2017; 16:199. [PMID: 29137634 PMCID: PMC5686817 DOI: 10.1186/s12934-017-0811-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 11/04/2017] [Indexed: 11/24/2022] Open
Abstract
Background Yeast transcription factors (TFs) involved in the regulation of multidrug resistance (MDR) were investigated in experiments with deletion mutants, transformants overexpressing synthetic genes encoding TFs, and toxic concentrations of lignocellulose-derived substances added to cultures as complex mixtures or as specific compounds, viz. coniferyl aldehyde, 5-hydroxymethylfurfural, and furfural. Results In the presence of complex mixtures of toxic substances from spruce wood, transformants overexpressing YAP1 and STB5, TFs involved in oxidative stress response, exhibited enhanced relative growth rates amounting to 4.589 ± 0.261 and 1.455 ± 0.185, respectively. Other TFs identified as important for resistance included DAL81, GZF3, LEU3, PUT3, and WAR1. Potential overlapping functions of YAP1 and STB5 were investigated in experiments with permutations of deletions and overexpression of the two genes. YAP1 complemented STB5 with respect to resistance to 5-hydroxymethylfurfural, but had a distinct role with regard to resistance to coniferyl aldehyde as deletion of YAP1 rendered the cell incapable of resisting coniferyl aldehyde even if STB5 was overexpressed. Conclusions We have investigated 30 deletion mutants and eight transformants overexpressing MDR transcription factors with regard to the roles the transcription factors play in the resistance to toxic concentrations of lignocellulose-derived substances. This work provides an overview of the involvement of thirty transcription factors in the resistance to lignocellulose-derived substances, shows distinct and complementary roles played by YAP1 and STB5, and offers directions for the engineering of robust yeast strains for fermentation processes based on lignocellulosic feedstocks.![]() Electronic supplementary material The online version of this article (10.1186/s12934-017-0811-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Guochao Wu
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden.
| | - Zixiang Xu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
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16
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Todhanakasem T, Yodsanga S, Sowatad A, Kanokratana P, Thanonkeo P, Champreda V. Inhibition analysis of inhibitors derived from lignocellulose pretreatment on the metabolic activity of Zymomonas mobilis
biofilm and planktonic cells and the proteomic responses. Biotechnol Bioeng 2017; 115:70-81. [DOI: 10.1002/bit.26449] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/29/2017] [Accepted: 09/04/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Tatsaporn Todhanakasem
- Department of Agro-Industry; Faculty of Biotechnology; Assumption University; Bangkok Thailand
| | - Supanika Yodsanga
- Department of Agro-Industry; Faculty of Biotechnology; Assumption University; Bangkok Thailand
| | - Apinya Sowatad
- Department of Agro-Industry; Faculty of Biotechnology; Assumption University; Bangkok Thailand
| | - Pattanop Kanokratana
- National Center for Genetic Engineering and Biotechnology (BIOTEC); Pathumthani Thailand
| | | | - Verawat Champreda
- National Center for Genetic Engineering and Biotechnology (BIOTEC); Pathumthani Thailand
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17
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Comparative assessment of fermentative capacity of different xylose-consuming yeasts. Microb Cell Fact 2017; 16:153. [PMID: 28903764 PMCID: PMC5598047 DOI: 10.1186/s12934-017-0766-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 09/07/2017] [Indexed: 12/03/2022] Open
Abstract
Background Understanding the effects of oxygen levels on yeast xylose metabolism would benefit ethanol production. In this work, xylose fermentative capacity of Scheffersomyces stipitis, Spathaspora passalidarum, Spathaspora arborariae and Candida tenuis was systematically compared under aerobic, oxygen-limited and anaerobic conditions. Results Fermentative performances of the four yeasts were greatly influenced by oxygen availability. S. stipitis and S. passalidarum showed the highest ethanol yields (above 0.44 g g−1) under oxygen limitation. However, S. passalidarum produced 1.5 times more ethanol than S. stipitis under anaerobiosis. While C. tenuis showed the lowest xylose consumption rate and incapacity to produce ethanol, S. arborariae showed an intermediate fermentative performance among the yeasts. NAD(P)H xylose reductase (XR) activity in crude cell extracts correlated with xylose consumption rates and ethanol production. Conclusions Overall, the present work demonstrates that the availability of oxygen influences the production of ethanol by yeasts and indicates that the NADH-dependent XR activity is a limiting step on the xylose metabolism. S. stipitis and S. passalidarum have the greatest potential for ethanol production from xylose. Both yeasts showed similar ethanol yields near theoretical under oxygen-limited condition. Besides that, S. passalidarum showed the best xylose consumption and ethanol production under anaerobiosis.
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18
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Influence of genetic background of engineered xylose-fermenting industrial Saccharomyces cerevisiae strains for ethanol production from lignocellulosic hydrolysates. J Ind Microbiol Biotechnol 2017; 44:1575-1588. [PMID: 28891041 DOI: 10.1007/s10295-017-1979-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 09/05/2017] [Indexed: 10/18/2022]
Abstract
An industrial ethanol-producing Saccharomyces cerevisiae strain with genes of fungal oxido-reductive pathway needed for xylose fermentation integrated into its genome (YRH1415) was used to obtain haploids and diploid isogenic strains. The isogenic strains were more effective in metabolizing xylose than YRH1415 strain and able to co-ferment glucose and xylose in the presence of high concentrations of inhibitors resulting from the hydrolysis of lignocellulosic biomass (switchgrass). The rate of xylose consumption did not appear to be affected by the ploidy of strains or the presence of two copies of the xylose fermentation genes but by heterozygosity of alleles for xylose metabolism in YRH1415. Furthermore, inhibitor tolerance was influenced by the heterozygous genome of the industrial strain, which also showed a marked influenced on tolerance to increasing concentrations of toxic compounds, such as furfural. In this work, selection of haploid derivatives was found to be a useful strategy to develop efficient xylose-fermenting industrial yeast strains.
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19
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Novy V, Wang R, Westman JO, Franzén CJ, Nidetzky B. Saccharomyces cerevisiae strain comparison in glucose-xylose fermentations on defined substrates and in high-gravity SSCF: convergence in strain performance despite differences in genetic and evolutionary engineering history. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:205. [PMID: 28878820 PMCID: PMC5584037 DOI: 10.1186/s13068-017-0887-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/12/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND The most advanced strains of xylose-fermenting Saccharomyces cerevisiae still utilize xylose far less efficiently than glucose, despite the extensive metabolic and evolutionary engineering applied in their development. Systematic comparison of strains across literature is difficult due to widely varying conditions used for determining key physiological parameters. Here, we evaluate an industrial and a laboratory S. cerevisiae strain, which has the assimilation of xylose via xylitol in common, but differ fundamentally in the history of their adaptive laboratory evolution development, and in the cofactor specificity of the xylose reductase (XR) and xylitol dehydrogenase (XDH). RESULTS In xylose and mixed glucose-xylose shaken bottle fermentations, with and without addition of inhibitor-rich wheat straw hydrolyzate, the specific xylose uptake rate of KE6-12.A (0.27-1.08 g gCDW-1 h-1) was 1.1 to twofold higher than that of IBB10B05 (0.10-0.82 g gCDW-1 h-1). KE6-12.A further showed a 1.1 to ninefold higher glycerol yield (0.08-0.15 g g-1) than IBB10B05 (0.01-0.09 g g-1). However, the ethanol yield (0.30-0.40 g g-1), xylitol yield (0.08-0.26 g g-1), and maximum specific growth rate (0.04-0.27 h-1) were in close range for both strains. The robustness of flocculating variants of KE6-12.A (KE-Flow) and IBB10B05 (B-Flow) was analyzed in high-gravity simultaneous saccharification and co-fermentation. As in shaken bottles, KE-Flow showed faster xylose conversion and higher glycerol formation than B-Flow, but final ethanol titres (61 g L-1) and cell viability were again comparable for both strains. CONCLUSIONS Individual specific traits, elicited by the engineering strategy, can affect global physiological parameters of S. cerevisiae in different and, sometimes, unpredictable ways. The industrial strain background and prolonged evolution history in KE6-12.A improved the specific xylose uptake rate more substantially than the superior XR, XDH, and xylulokinase activities were able to elicit in IBB10B05. Use of an engineered XR/XDH pathway in IBB10B05 resulted in a lower glycerol rather than a lower xylitol yield. However, the strain development programs were remarkably convergent in terms of the achieved overall strain performance. This highlights the importance of comparative strain evaluation to advance the engineering strategies for next-generation S. cerevisiae strain development.
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Affiliation(s)
- Vera Novy
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Graz, Austria
| | - Ruifei Wang
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Johan O Westman
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Carl Johan Franzén
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Graz, Austria
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Jansen MLA, Bracher JM, Papapetridis I, Verhoeven MD, de Bruijn H, de Waal PP, van Maris AJA, Klaassen P, Pronk JT. Saccharomyces cerevisiae strains for second-generation ethanol production: from academic exploration to industrial implementation. FEMS Yeast Res 2017; 17:3868933. [PMID: 28899031 PMCID: PMC5812533 DOI: 10.1093/femsyr/fox044] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/15/2017] [Indexed: 11/18/2022] Open
Abstract
The recent start-up of several full-scale 'second generation' ethanol plants marks a major milestone in the development of Saccharomyces cerevisiae strains for fermentation of lignocellulosic hydrolysates of agricultural residues and energy crops. After a discussion of the challenges that these novel industrial contexts impose on yeast strains, this minireview describes key metabolic engineering strategies that have been developed to address these challenges. Additionally, it outlines how proof-of-concept studies, often developed in academic settings, can be used for the development of robust strain platforms that meet the requirements for industrial application. Fermentation performance of current engineered industrial S. cerevisiae strains is no longer a bottleneck in efforts to achieve the projected outputs of the first large-scale second-generation ethanol plants. Academic and industrial yeast research will continue to strengthen the economic value position of second-generation ethanol production by further improving fermentation kinetics, product yield and cellular robustness under process conditions.
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Affiliation(s)
- Mickel L. A. Jansen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Jasmine M. Bracher
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Ioannis Papapetridis
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Maarten D. Verhoeven
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Hans de Bruijn
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Paul P. de Waal
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Antonius J. A. van Maris
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Paul Klaassen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
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21
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van Niel EWJ, Bergdahl B, Hahn-Hägerdal B. Close to the Edge: Growth Restrained by the NAD(P)H/ATP Formation Flux Ratio. Front Microbiol 2017; 8:1149. [PMID: 28690597 PMCID: PMC5479917 DOI: 10.3389/fmicb.2017.01149] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 06/07/2017] [Indexed: 11/13/2022] Open
Abstract
Most fermentative microorganisms grow well-under anaerobic conditions managing a balanced redox and appropriate energy metabolism, but a few species do exist in which cells have to cope with inadequate energy recovery or capture and/or redox balancing. Two cases of these species, i.e., the metabolically engineered Saccharomyces cerevisiae enabling it to ferment xylose and Lactobacillus reuteri fermenting glucose via the phosphoketolase pathway, are here used to introduce a quantification parameter to capture what limits the growth rate of these microorganisms under anaerobic conditions. This dimensionless parameter, the cofactor formation flux ratio (RJ), is the ratio between the redox formation flux (JNADH+NADPH), and the energy carrier formation flux (JATP), which are mainly connected to the central carbon pathways. Data from metabolic flux analyses performed in previous and present studies were used to estimate the RJ-values. Even though both microorganisms possess different central pathways, a similar relationship between RJ and the specific growth rate (μ) was found. Furthermore, for both microorganisms external electron acceptors moderately reduced the RJ-value, thereby raising the μ accordingly. Based on the emerging profile of this relationship an interpretation is presented suggesting that this quantitative analysis can be applied beyond the two microbial species experimentally investigated in the current study to provide data for future targeted strain development strategies.
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Affiliation(s)
- Ed W J van Niel
- Division of Applied Microbiology, Lund UniversityLund, Sweden
| | - Basti Bergdahl
- Division of Applied Microbiology, Lund UniversityLund, Sweden
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22
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Li YC, Gou ZX, Zhang Y, Xia ZY, Tang YQ, Kida K. Inhibitor tolerance of a recombinant flocculating industrial Saccharomyces cerevisiae strain during glucose and xylose co-fermentation. Braz J Microbiol 2017. [PMID: 28629968 PMCID: PMC5628316 DOI: 10.1016/j.bjm.2016.11.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Lignocellulose-derived inhibitors have negative effects on the ethanol fermentation capacity of Saccharomyces cerevisiae. In this study, the effects of eight typical inhibitors, including weak acids, furans, and phenols, on glucose and xylose co-fermentation of the recombinant xylose-fermenting flocculating industrial S. cerevisiae strain NAPX37 were evaluated by batch fermentation. Inhibition on glucose fermentation, not that on xylose fermentation, correlated with delayed cell growth. The weak acids and the phenols showed additive effects. The effect of inhibitors on glucose fermentation was as follows (from strongest to weakest): vanillin > phenol > syringaldehyde > 5-HMF > furfural > levulinic acid > acetic acid > formic acid. The effect of inhibitors on xylose fermentation was as follows (from strongest to weakest): phenol > vanillin > syringaldehyde > furfural > 5-HMF > formic acid > levulinic acid > acetic acid. The NAPX37 strain showed substantial tolerance to typical inhibitors and showed good fermentation characteristics, when a medium with inhibitor cocktail or rape straw hydrolysate was used. This research provides important clues for inhibitors tolerance of recombinant industrial xylose-fermenting S. cerevisiae.
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Affiliation(s)
- Yun-Cheng Li
- College of Architecture and Environment, Sichuan University, Chengdu, China; College of Pharmacy and Bioengineering, Chengdu University, Chengdu, China
| | - Zi-Xi Gou
- College of Architecture and Environment, Sichuan University, Chengdu, China
| | - Ying Zhang
- College of Architecture and Environment, Sichuan University, Chengdu, China
| | - Zi-Yuan Xia
- College of Architecture and Environment, Sichuan University, Chengdu, China
| | - Yue-Qin Tang
- College of Architecture and Environment, Sichuan University, Chengdu, China.
| | - Kenji Kida
- College of Architecture and Environment, Sichuan University, Chengdu, China
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Ishida Y, Nguyen TTM, Izawa S. The yeast ADH7 promoter enables gene expression under pronounced translation repression caused by the combined stress of vanillin, furfural, and 5-hydroxymethylfurfural. J Biotechnol 2017; 252:65-72. [DOI: 10.1016/j.jbiotec.2017.04.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/03/2017] [Accepted: 04/21/2017] [Indexed: 11/30/2022]
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24
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Wang S, He Z, Yuan Q. Xylose enhances furfural tolerance in Candida tropicalis by improving NADH recycle. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2016.09.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Tramontina R, Franco Cairo JPL, Liberato MV, Mandelli F, Sousa A, Santos S, Rabelo SC, Campos B, Ienczak J, Ruller R, Damásio ARL, Squina FM. The Coptotermes gestroi aldo-keto reductase: a multipurpose enzyme for biorefinery applications. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:4. [PMID: 28053664 PMCID: PMC5209882 DOI: 10.1186/s13068-016-0688-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 12/14/2016] [Indexed: 05/07/2023]
Abstract
BACKGROUND In nature, termites can be considered as a model biological system for biofuel research based on their remarkable efficiency for lignocellulosic biomass conversion. Redox enzymes are of interest in second-generation ethanol production because they promote synergic enzymatic activity with classical hydrolases for lignocellulose saccharification and inactivate fermentation inhibitory compounds produced after lignocellulose pretreatment steps. RESULTS In the present study, the biochemical and structural characteristics of the Coptotermes gestroi aldo-keto reductase (CgAKR-1) were comprehensively investigated. CgAKR-1 displayed major structural differences compared with others AKRs, including the differences in the amino acid composition of the substrate-binding site, providing basis for classification as a founding member of a new AKR subfamily (family AKR1 I). Immunolocalization assays with anti-CgAKR-1 antibodies resulted in strong fluorescence in the salivary gland, proventriculus, and foregut. CgAKR-1 supplementation caused a 32% reduction in phenolic aldehydes, such as furfural, which act as fermentation inhibitors of hemicellulosic hydrolysates, and improved ethanol fermentation by the xylose-fermenting yeast Scheffersomyces stipitis by 45%. We observed synergistic enzymatic interactions between CgAKR-1 and commercial cellulosic cocktail for sugarcane bagasse saccharification, with a maximum synergism degree of 2.17 for sugar release. Our data indicated that additive enzymatic activity could be mediated by reactive oxygen species because CgAKR-1 could produce hydrogen peroxide. CONCLUSION In summary, we identified the founding member of an AKRI subfamily with a potential role in the termite digestome. CgAKR-1 was found to be a multipurpose enzyme with potential biotechnological applications. The present work provided a basis for the development and application of integrative and multipurpose enzymes in the bioethanol production chain.
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Affiliation(s)
- Robson Tramontina
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
- Programa de Pós Graduação em Biociências e Tecnologia de Produtos Bioativos (BTPB)-Instituto de Biologia-CP 6109, Universidade Estadual de Campinas-UNICAMP, 13083-970 Campinas, SP Brazil
| | - João Paulo L. Franco Cairo
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
| | - Marcelo V. Liberato
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
| | - Fernanda Mandelli
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
| | - Amanda Sousa
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
- Programa de Pós Graduação em Biociências e Tecnologia de Produtos Bioativos (BTPB)-Instituto de Biologia-CP 6109, Universidade Estadual de Campinas-UNICAMP, 13083-970 Campinas, SP Brazil
| | - Samantha Santos
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
| | - Sarita Cândida Rabelo
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
| | - Bruna Campos
- Brazilian Biosciences National Laboratory (LNBio), from the Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Jaciane Ienczak
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
| | - Roberto Ruller
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
| | - André R. L. Damásio
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP Brazil
| | - Fabio Marcio Squina
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Rua Giuseppe Máximo Scolfaro, no 10000 Campinas, SP Brazil
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Zhang GC, Kong II, Wei N, Peng D, Turner TL, Sung BH, Sohn JH, Jin YS. Optimization of an acetate reduction pathway for producing cellulosic ethanol by engineered yeast. Biotechnol Bioeng 2016; 113:2587-2596. [DOI: 10.1002/bit.26021] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/24/2016] [Accepted: 05/27/2016] [Indexed: 01/17/2023]
Affiliation(s)
- Guo-Chang Zhang
- Carl R. Woese Institute for Genomic Biology; University of Illinois at Urbana-Champaign; Urbana Illinois 61801
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
| | - In Iok Kong
- Carl R. Woese Institute for Genomic Biology; University of Illinois at Urbana-Champaign; Urbana Illinois 61801
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
| | - Na Wei
- Department of Civil and Environmental Engineering and Earth Sciences; University of Notre Dame; South Bend Indiana
| | - Dairong Peng
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
| | - Timothy L. Turner
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
| | - Bong Hyun Sung
- Bioenergy and Biochemical Research Center; Korea Research Institute of Bioscience and Biotechnology; Daejeon Korea
| | - Jung-Hoon Sohn
- Bioenergy and Biochemical Research Center; Korea Research Institute of Bioscience and Biotechnology; Daejeon Korea
| | - Yong-Su Jin
- Carl R. Woese Institute for Genomic Biology; University of Illinois at Urbana-Champaign; Urbana Illinois 61801
- Department of Food Science and Human Nutrition; University of Illinois at Urbana-Champaign; Urbana Illinois
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Nielsen F, Zacchi G, Galbe M, Wallberg O. Prefermentation improves ethanol yield in separate hydrolysis and cofermentation of steam-pretreated wheat straw. ACTA ACUST UNITED AC 2016. [DOI: 10.1186/s40508-016-0054-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Wang H, Li L, Zhang L, An J, Cheng H, Deng Z. Xylitol production from waste xylose mother liquor containing miscellaneous sugars and inhibitors: one-pot biotransformation by Candida tropicalis and recombinant Bacillus subtilis. Microb Cell Fact 2016; 15:82. [PMID: 27184671 PMCID: PMC4869185 DOI: 10.1186/s12934-016-0480-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 05/03/2016] [Indexed: 11/10/2022] Open
Abstract
Background The process of industrial xylitol production is a massive source of organic pollutants, such as waste xylose mother liquor (WXML), a viscous reddish-brown liquid. Currently, WXML is difficult to reuse due to its miscellaneous low-cost sugars, high content of inhibitors and complex composition. WXML, as an organic pollutant of hemicellulosic hydrolysates, accumulates and has become an issue of industrial concern in China. Previous studies have focused only on the catalysis of xylose in the hydrolysates into xylitol using one strain, without considering the removal of other miscellaneous sugars, thus creating an obstacle to subsequent large-scale purification. In the present study, we aimed to develop a simple one-pot biotransformation to produce high-purity xylitol from WXML to improve its economic value. Results In the present study, we developed a procedure to produce xylitol from WXML, which combines detoxification, biotransformation and removal of by-product sugars (purification) in one bioreactor using two complementary strains, Candida tropicalis X828 and Bacillus subtilis Bs12. At the first stage of micro-aerobic biotransformation, the yeast cells were allowed to grow and metabolized glucose and the inhibitors furfural and hydroxymethyl furfural (HMF), and converted xylose into xylitol. At the second stage of aerobic biotransformation, B. subtilis Bs12 was activated and depleted the by-product sugars. The one-pot process was successfully scaled up from shake flasks to 5, 150 L and 30 m3 bioreactors. Approximately 95 g/L of pure xylitol could be obtained from the medium containing 400 g/L of WXML at a yield of 0.75 g/g xylose consumed, and the by-product sugars glucose, l-arabinose and galactose were depleted simultaneously. Conclusions Our results demonstrate that the one-pot procedure is a viable option for the industrial application of WXML to produce value-added chemicals. The integration of complementary strains in the biotransformation of hemicellulosic hydrolysates is efficient under optimized conditions. Moreover, our study of one-pot biotransformation also provides useful information on the combination of biotechnological processes for the biotransformation of other compounds.
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Affiliation(s)
- Hengwei Wang
- Innovation and Application Institute (IAI), Zhejiang Ocean University, Zhoushan, 316022, China
| | - Lijuan Li
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Lebin Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jin An
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hairong Cheng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
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Moysés DN, Reis VCB, de Almeida JRM, de Moraes LMP, Torres FAG. Xylose Fermentation by Saccharomyces cerevisiae: Challenges and Prospects. Int J Mol Sci 2016; 17:207. [PMID: 26927067 PMCID: PMC4813126 DOI: 10.3390/ijms17030207] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/23/2016] [Accepted: 01/27/2016] [Indexed: 12/17/2022] Open
Abstract
Many years have passed since the first genetically modified Saccharomyces cerevisiae strains capable of fermenting xylose were obtained with the promise of an environmentally sustainable solution for the conversion of the abundant lignocellulosic biomass to ethanol. Several challenges emerged from these first experiences, most of them related to solving redox imbalances, discovering new pathways for xylose utilization, modulation of the expression of genes of the non-oxidative pentose phosphate pathway, and reduction of xylitol formation. Strategies on evolutionary engineering were used to improve fermentation kinetics, but the resulting strains were still far from industrial application. Lignocellulosic hydrolysates proved to have different inhibitors derived from lignin and sugar degradation, along with significant amounts of acetic acid, intrinsically related with biomass deconstruction. This, associated with pH, temperature, high ethanol, and other stress fluctuations presented on large scale fermentations led the search for yeasts with more robust backgrounds, like industrial strains, as engineering targets. Some promising yeasts were obtained both from studies of stress tolerance genes and adaptation on hydrolysates. Since fermentation times on mixed-substrate hydrolysates were still not cost-effective, the more selective search for new or engineered sugar transporters for xylose are still the focus of many recent studies. These challenges, as well as under-appreciated process strategies, will be discussed in this review.
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Affiliation(s)
- Danuza Nogueira Moysés
- Departamento de Biologia Celular, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
- Petrobras Research and Development Center, Biotechnology Management, Rio de Janeiro, RJ 21941-915, Brazil.
| | | | - João Ricardo Moreira de Almeida
- Embrapa Agroenergia, Laboratório de Genética e Biotecnologia, Parque Estação Biológica s/n, Av. W3 Norte, Brasília, DF 70770-901, Brazil.
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Continuous co-production of ethanol and xylitol from rice straw hydrolysate in a membrane bioreactor. Folia Microbiol (Praha) 2015; 61:179-89. [DOI: 10.1007/s12223-015-0420-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 08/18/2015] [Indexed: 10/23/2022]
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31
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Cunha JT, Aguiar TQ, Romaní A, Oliveira C, Domingues L. Contribution of PRS3, RPB4 and ZWF1 to the resistance of industrial Saccharomyces cerevisiae CCUG53310 and PE-2 strains to lignocellulosic hydrolysate-derived inhibitors. BIORESOURCE TECHNOLOGY 2015; 191:7-16. [PMID: 25974617 DOI: 10.1016/j.biortech.2015.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 04/30/2015] [Accepted: 05/02/2015] [Indexed: 05/13/2023]
Abstract
PRS3, RPB4 and ZWF1 were previously identified as key genes for yeast tolerance to lignocellulose-derived inhibitors. To better understand their contribution to yeast resistance to the multiple stresses occurring during lignocellulosic hydrolysate fermentations, we overexpressed these genes in two industrial Saccharomyces cerevisiae strains, CCUG53310 and PE-2, and evaluated their impact on the fermentation of Eucalyptus globulus wood and corn cob hydrolysates. PRS3 overexpression improved the fermentation rate (up to 32%) and productivity (up to 48%) in different hydrolysates. ZWF1 and RPB4 overexpression did not improve the fermentation performance, but their increased expression in the presence of acetic acid, furfural and hydroxymethylfurfural was found to contribute to yeast adaptation to these inhibitors. This study expands our understanding about the molecular mechanisms involved in industrial yeast tolerance to the stresses occurring during lignocellulosic bioethanol production and highlights the importance of selecting appropriate strain backgrounds/hydrolysates combinations when addressing further improvement of these processes.
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Affiliation(s)
- Joana T Cunha
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Tatiana Q Aguiar
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Aloia Romaní
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Carla Oliveira
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal.
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Wang S, Li H, Fan X, Zhang J, Tang P, Yuan Q. Metabolic responses in Candida tropicalis to complex inhibitors during xylitol bioconversion. Fungal Genet Biol 2015; 82:1-8. [PMID: 26127015 DOI: 10.1016/j.fgb.2015.04.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 04/07/2015] [Accepted: 04/14/2015] [Indexed: 01/10/2023]
Abstract
During xylitol fermentation, Candida tropicalis is often inhibited by inhibitors in hemicellulose hydrolysate. The mechanisms involved in the metabolic responses to inhibitor stress and the resistances to inhibitors are still not clear. To understand the inhibition mechanisms and the metabolic responses to inhibitors, a GC/MS-based metabolomics approach was performed on C. tropicalis treated with and without complex inhibitors (CI, including furfural, phenol and acetic acid). Partial least squares discriminant analysis was used to determine the metabolic variability between CI-treated groups and control groups, and 25 metabolites were identified as possible entities responsible for the discrimination caused by inhibitors. We found that xylose uptake rate and xylitol oxidation rate were promoted by CI treatment. Metabolomics analysis showed that the flux from xylulose to pentose phosphate pathway increased, and tricarboxylic acid cycle was disturbed by CI. Moreover, the changes in levels of 1,3-propanediol, trehalose, saturated fatty acids and amino acids showed different mechanisms involved in metabolic responses to inhibitor stress. The increase of 1,3-propanediol was considered to be correlated with regulating redox balance and osmoregulation. The increase of trehalose might play a role in protein stabilization and cellular membranes protection. Saturated fatty acids could cause the decrease of membrane fluidity and make the plasma membrane rigid to maintain the integrity of plasma membrane. The deeper understanding of the inhibition mechanisms and the metabolic responses to inhibitors will provide us with more information on the metabolism regulation during xylitol bioconversion and the construction of industrial strains with inhibitor tolerance for better utilization of bioresource.
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Affiliation(s)
- Shizeng Wang
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Hao Li
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Xiaoguang Fan
- Key Laboratory of Industrial Microbiology of Education Ministry, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China
| | - Jingkun Zhang
- Key Laboratory of Industrial Microbiology of Education Ministry, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China
| | - Pingwah Tang
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Qipeng Yuan
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China.
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Phenolic Amides Are Potent Inhibitors of De Novo Nucleotide Biosynthesis. Appl Environ Microbiol 2015; 81:5761-72. [PMID: 26070680 PMCID: PMC4551265 DOI: 10.1128/aem.01324-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 06/09/2015] [Indexed: 12/17/2022] Open
Abstract
An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposure leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using 13C-labeled sugars and [15N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. The results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals.
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Pornkamol U, Franzen CJ. Dynamic flux balancing elucidates NAD(P)H production as limiting response to furfural inhibition in Saccharomyces cerevisiae. Biotechnol J 2015; 10:1248-58. [PMID: 25880365 DOI: 10.1002/biot.201400833] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 02/13/2015] [Accepted: 04/13/2015] [Indexed: 12/20/2022]
Abstract
Achieving efficient and economical lignocellulose-based bioprocess requires a robust organism tolerant to furfural, a major inhibitory compound present in lignocellulosic hydrolysate. The aim of this study was to develop a model that could generate quantitative descriptions of cell metabolism for elucidating the cell's adaptive response to furfural. Such a modelling tool could provide strategies for the design of more robust cells. A dynamic flux balance (dFBA) model of Saccharomyces cerevisiae was created by coupling a kinetic fermentation model with a previously published genome-scale stoichiometric model. The dFBA model was used for studying intracellular and extracellular flux responses to furfural perturbations under steady state and dynamic conditions. The predicted effects of furfural on dynamic flux profiles agreed well with previously published experimental results. The model showed that the yeast cell adjusts its metabolism in response to furfural challenge by increasing fluxes through the pentose phosphate pathway, TCA cycle, and proline and serine biosynthesis in order to meet the high demand of NAD(P)H cofactors. The model described here can be used to aid in systematic optimization of the yeast, as well as of the fermentation process, for efficient lignocellulosic ethanol production.
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Affiliation(s)
- Unrean Pornkamol
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand.
| | - Carl J Franzen
- Chalmers University of Technology, Department of Chemical and Biological Engineering, Division of Life Science - Industrial Biotechnology, Gothenburg, Sweden
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Effect of carbonyl inhibitors and their H₂O₂ detoxification on lactic acid fermentation. Appl Biochem Biotechnol 2015; 175:3657-72. [PMID: 25666370 DOI: 10.1007/s12010-015-1533-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/01/2015] [Indexed: 10/24/2022]
Abstract
Biomass degradation compounds significantly inhibit biochemical conversion of biomass prehydrolysates to biofuels and chemicals, such as lactic acid. To characterize the structure-activity relationship of carbonyl inhibition on lactic acid fermentation, we examined effects of eight carbonyl compounds (furfural, 5-hydroxymethyl furfural, vanillin, syringaldehyde, 4-hydroxybenzaldehyde, phthalaldehyde, benzoic acid, and pyrogallol aldehyde) and creosol on lactic acid production by Lactobacillus delbrueckii. Pyrogallol aldehyde reduced the cell growth rate by 35 % at 1.0 mM and inhibited lactic acid production completely at 2.0 mM. By correlating the molecular descriptors to the inhibition constants in lactic acid fermentation, we found a good relationship between the hydrophobicity (Log P) of aldehydes and their inhibition constants in fermentation. The inhibitory effect of carbonyl inhibitors appeared to correlate with their thiol reactivity as well. In addition, we found that H2O2 detoxified pyrogallol aldehyde and phthalaldehyde inhibitory activity. H2O2 detoxification was applied to real biomass prehydrolysates in lactic acid fermentation.
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36
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Nielsen F, Tomás-Pejó E, Olsson L, Wallberg O. Short-term adaptation during propagation improves the performance of xylose-fermenting Saccharomyces cerevisiae in simultaneous saccharification and co-fermentation. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:219. [PMID: 26697108 PMCID: PMC4687142 DOI: 10.1186/s13068-015-0399-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/30/2015] [Indexed: 05/15/2023]
Abstract
BACKGROUND Inhibitors that are generated during thermochemical pretreatment and hydrolysis impair the performance of microorganisms during fermentation of lignocellulosic hydrolysates. In omitting costly detoxification steps, the fermentation process relies extensively on the performance of the fermenting microorganism. One attractive option of improving its performance and tolerance to microbial inhibitors is short-term adaptation during propagation. This study determined the influence of short-term adaptation on the performance of recombinant Saccharomyces cerevisiae in simultaneous saccharification and co-fermentation (SSCF). The aim was to understand how short-term adaptation with lignocellulosic hydrolysate affects the cell mass yield of propagated yeast and performance in subsequent fermentation steps. The physiology of propagated yeast was examined with regard to viability, vitality, stress responses, and upregulation of relevant genes to identify any links between the beneficial traits that are promoted during adaptation and overall ethanol yields in co-fermentation. RESULTS The presence of inhibitors during propagation significantly improved fermentation but lowered cell mass yield during propagation. Xylose utilization of adapted cultures was enhanced by increasing amounts of hydrolysate in the propagation. Ethanol yields improved by over 30 % with inhibitor concentrations that corresponded to ≥2.5 % water-insoluble solids (WIS) load during the propagation compared with the unadapted culture. Adaptation improved cell viability by >10 % and increased vitality by >20 %. Genes that conferred resistance against inhibitors were upregulated with increasing amounts of inhibitors during the propagation, but the adaptive response was not associated with improved ethanol yields in SSCF. The positive effects in SSCF were observed even with adaptation at inhibitor concentrations that corresponded to 2.5 % WIS. Higher amounts of hydrolysate in the propagation feed further improved the fermentation but increased the variability in fermentation outcomes and resulted in up to 20 % loss of cell mass yield. CONCLUSIONS Short-term adaptation during propagation improves the tolerance of inhibitor-resistant yeast strains to inhibitors in lignocellulosic hydrolysates and improves their ethanol yield in fermentation and xylose-fermenting capacity. A low amount of hydrolysate (corresponding to 2.5 % WIS) is optimal, whereas higher amounts decrease cell mass yield during propagation.
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Affiliation(s)
- Fredrik Nielsen
- />Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund, Sweden
| | - Elia Tomás-Pejó
- />Department of Biology and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
- />Unit of Biotechnological Processes for Energy Production, IMDEA Energy, 28935 Móstoles, Spain
| | - Lisbeth Olsson
- />Department of Biology and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Ola Wallberg
- />Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund, Sweden
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Jiang W, Chang S, Li H, Oleskowicz-Popiel P, Xu J. Liquid hot water pretreatment on different parts of cotton stalk to facilitate ethanol production. BIORESOURCE TECHNOLOGY 2015; 176:175-180. [PMID: 25461000 DOI: 10.1016/j.biortech.2014.11.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/06/2014] [Accepted: 11/08/2014] [Indexed: 06/04/2023]
Abstract
To investigate pretreatment demand for different parts of biomass, cotton stalk was separated into stem, branch and boll shell, which were treated by liquid hot water pretreatment (LHWP) with severity from 2.77 to 4.42. Based on weight loss (WL, w/w) mainly caused by hemicellulose removal, it was found that boll shell (WL, 46.93%) was more sensitive to LHWP than stem (WL, 38.85%). Although ethanol yield of 18.3, 16.27 and 21.08g/100g was achieved from stem, branch and boll shell with pretreatment severity at 4.42, ratio of ethanol yield to pretreatment energy input for particular parts was different. For boll shell and branch, the maximum ratio of ethanol yield to energy input were 1.37 and 1.33g ethanolkJ(-1) with severity at 4.34, while it was 1.20 for stem at 3.66. This indicates that different pretreatment demands for different parts of plants should be considered in order to save pretreatment energy input.
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Affiliation(s)
- Wei Jiang
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Senlin Chang
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Hongqiang Li
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Piotr Oleskowicz-Popiel
- Poznan University of Technology, Faculty of Civil and Environmental Engineering, Institute of Environmental Engineering, Berdychowo 4, 60-965 Poznan, Poland
| | - Jian Xu
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
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Field SJ, Ryden P, Wilson D, James SA, Roberts IN, Richardson DJ, Waldron KW, Clarke TA. Identification of furfural resistant strains of Saccharomyces cerevisiae and Saccharomyces paradoxus from a collection of environmental and industrial isolates. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:33. [PMID: 25861389 PMCID: PMC4389715 DOI: 10.1186/s13068-015-0217-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 02/02/2015] [Indexed: 05/11/2023]
Abstract
BACKGROUND Fermentation of bioethanol using lignocellulosic biomass as a raw material provides a sustainable alternative to current biofuel production methods by utilising waste food streams as raw material. Before lignocellulose can be fermented, it requires physical, chemical and enzymatic treatment in order to release monosaccharides, a process that causes the chemical transformation of glucose and xylose into the cyclic aldehydes furfural and hydroxyfurfural. These furan compounds are potent inhibitors of Saccharomyces fermentation, and consequently furfural tolerant strains of Saccharomyces are required for lignocellulosic fermentation. RESULTS This study investigated yeast tolerance to furfural and hydroxyfurfural using a collection of 71 environmental and industrial isolates of the baker's yeast Saccharomyces cerevisiae and its closest relative Saccharomyces paradoxus. The Saccharomyces strains were initially screened for growth on media containing 100 mM glucose and 1.5 mg ml(-1) furfural. Five strains were identified that showed a significant tolerance to growth in the presence of furfural, and these were then screened for growth and ethanol production in the presence of increasing amounts (0.1 to 4 mg ml(-1)) of furfural. CONCLUSIONS Of the five furfural tolerant strains, S. cerevisiae National Collection of Yeast Cultures (NCYC) 3451 displayed the greatest furfural resistance and was able to grow in the presence of up to 3.0 mg ml(-1) furfural. Furthermore, ethanol production in this strain did not appear to be inhibited by furfural, with the highest ethanol yield observed at 3.0 mg ml(-1) furfural. Although furfural resistance was not found to be a trait specific to any one particular lineage or population, three of the strains were isolated from environments where they might be continually exposed to low levels of furfural through the ongoing natural degradation of lignocelluloses, and would therefore develop elevated levels of resistance to these furan compounds. Thus, these strains represent good candidates for future studies of genetic variation relevant to understanding and manipulating furfural resistance and in the development of tolerant ethanologenic yeast strains for use in bioethanol production from lignocellulose processing.
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Affiliation(s)
- Sarah J Field
- />School of Biological Sciences, University of East Anglia, Norwich, NR4 7JN UK
| | - Peter Ryden
- />Biorefinery Centre, Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA UK
| | - David Wilson
- />Biorefinery Centre, Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA UK
| | - Stephen A James
- />National Collection of Yeast Cultures, Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA UK
| | - Ian N Roberts
- />National Collection of Yeast Cultures, Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA UK
| | - David J Richardson
- />School of Biological Sciences, University of East Anglia, Norwich, NR4 7JN UK
| | - Keith W Waldron
- />Biorefinery Centre, Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA UK
| | - Thomas A Clarke
- />School of Biological Sciences, University of East Anglia, Norwich, NR4 7JN UK
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Zhang S, Winestrand S, Chen L, Li D, Jönsson LJ, Hong F. Tolerance of the nanocellulose-producing bacterium Gluconacetobacter xylinus to lignocellulose-derived acids and aldehydes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:9792-9. [PMID: 25186182 DOI: 10.1021/jf502623s] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Lignocellulosic biomass serves as a potential alternative feedstock for production of bacterial nanocellulose (BNC), a high-value-added product of bacteria such as Gluconacetobacter xylinus. The tolerance of G. xylinus to lignocellulose-derived inhibitors (formic acid, acetic acid, levulinic acid, furfural, and 5-hydroxymethylfurfural) was investigated. Whereas 100 mM formic acid completely suppressed the metabolism of G. xylinus, 250 mM of either acetic acid or levulinic acid still allowed glucose metabolism and BNC production to occur. Complete suppression of glucose utilization and BNC production was observed after inclusion of 20 and 30 mM furfural and 5-hydroxymethylfurfural, respectively. The bacterium oxidized furfural and 5-hydroxymethylfurfural to furoic acid and 5-hydroxymethyl-2-furoic acid, respectively. The highest yields observed were 88% for furoic acid/furfural and 76% for 5-hydroxymethyl-2-furoic acid/5-hydroxymethylfurfural. These results are the first demonstration of the capability of G. xylinus to tolerate lignocellulose-derived inhibitors and to convert furan aldehydes.
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Affiliation(s)
- Shuo Zhang
- China-Sweden Associated Research Laboratory in Industrial Biotechnology and ‡Group of Microbiological Engineering and Industrial Biotechnology, College of Chemistry, Chemical Engineering and Biotechnology, and #School of Environmental Science and Engineering, Donghua University , Shanghai 201620, China
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Laadan B, Wallace-Salinas V, Carlsson ÅJ, Almeida JR, Rådström P, Gorwa-Grauslund MF. Furaldehyde substrate specificity and kinetics of Saccharomyces cerevisiae alcohol dehydrogenase 1 variants. Microb Cell Fact 2014; 13:112. [PMID: 25287956 PMCID: PMC4423641 DOI: 10.1186/s12934-014-0112-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 07/23/2014] [Indexed: 01/16/2023] Open
Abstract
Background A previously discovered mutant of Saccharomyces cerevisiae alcohol dehydrogenase 1 (Adh1p) was shown to enable a unique NADH-dependent reduction of 5-hydroxymethylfurfural (HMF), a well-known inhibitor of yeast fermentation. In the present study, site-directed mutagenesis of both native and mutated ADH1 genes was performed in order to identify the key amino acids involved in this substrate shift, resulting in Adh1p-variants with different substrate specificities. Results In vitro activities of the Adh1p-variants using two furaldehydes, HMF and furfural, revealed that HMF reduction ability could be acquired after a single amino acid substitution (Y295C). The highest activity, however, was reached with the double mutation S110P Y295C. Kinetic characterization with both aldehydes and the in vivo primary substrate acetaldehyde also enabled to correlate the alterations in substrate affinity with the different amino acid substitutions. Conclusions We demonstrated the key role of Y295C mutation in HMF reduction by Adh1p. We generated and kinetically characterized a group of protein variants using two furaldehyde compounds of industrial relevance. Also, we showed that there is a threshold after which higher in vitro HMF reduction activities do not correlate any more with faster in vivo rates of HMF conversion, indicating other cell limitations in the conversion of HMF.
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Affiliation(s)
- Boaz Laadan
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-22100, Lund, Sweden.
| | - Valeria Wallace-Salinas
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-22100, Lund, Sweden.
| | - Åsa Janfalk Carlsson
- Department of Chemistry-BMC, Uppsala University, Box 576, SE-751 23, Uppsala, Sweden.
| | - João Rm Almeida
- Embrapa Agroenergy, Parque Estação Biológica, PqEB, W3 Norte (Final), 70770-901, Brasília, DF, Brazil.
| | - Peter Rådström
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-22100, Lund, Sweden.
| | - Marie F Gorwa-Grauslund
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-22100, Lund, Sweden.
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Ujor V, Agu CV, Gopalan V, Ezeji TC. Glycerol supplementation of the growth medium enhances in situ detoxification of furfural by Clostridium beijerinckii during butanol fermentation. Appl Microbiol Biotechnol 2014; 98:6511-21. [PMID: 24839212 DOI: 10.1007/s00253-014-5802-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 04/14/2014] [Accepted: 04/27/2014] [Indexed: 01/01/2023]
Abstract
Lignocellulose-derived microbial inhibitors such as furfural and 5-hydroxymethyl furfural adversely affect fermentation of lignocellulosic biomass hydrolysates to fuels and chemicals due to their toxicity on fermenting microbes. To harness the potential of lignocellulose as a cheap source of fermentable sugars, in situ detoxification of furfural and other lignocellulose-derived microbial inhibitors is essential. To enhance in situ detoxification and tolerance of furfural by Clostridium beijerinckii NCIMB 8052 during acetone-butanol-ethanol (ABE) fermentation, the effect of glycerol on NADH/NADPH generation and ABE production by furfural (4, 5, and 6 g/L)-challenged cultures was investigated in this study. In all instances, beneficial outcomes were observed. For example, the fermentation medium supplemented with glycerol and subjected to 5 g/L furfural elicited up to 1.8- and 3-fold increases, respectively, in NADH and NADPH levels in C. beijerinckii 8052 relative to the control culture. These critical changes are the likely underpinnings for the glycerol-mediated 2.3-fold increase in the rate of detoxification of 5 g/L furfural, substrate consumption, and ABE production compared to the unsupplemented medium. Collectively, these results demonstrate that increased intracellular NADH/NADPH in C. beijerinckii 8052 due to glycerol utilization engenders favorable effects on many aspects of cellular metabolism, including enhanced furfural reduction and increased ABE production.
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Affiliation(s)
- Victor Ujor
- Department of Animal Sciences and Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, 305 Gerlaugh Hall, 1680 Madison Avenue, Wooster, OH, 44691, USA
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42
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Smith J, van Rensburg E, Görgens JF. Simultaneously improving xylose fermentation and tolerance to lignocellulosic inhibitors through evolutionary engineering of recombinant Saccharomyces cerevisiae harbouring xylose isomerase. BMC Biotechnol 2014; 14:41. [PMID: 24884721 PMCID: PMC4026109 DOI: 10.1186/1472-6750-14-41] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 05/06/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Yeasts tolerant to toxic inhibitors from steam-pretreated lignocellulose with xylose co-fermentation capability represent an appealing approach for 2nd generation ethanol production. Whereas rational engineering, mutagenesis and evolutionary engineering are established techniques for either improved xylose utilisation or enhancing yeast tolerance, this report focuses on the simultaneous enhancement of these attributes through mutagenesis and evolutionary engineering of Saccharomyces cerevisiae harbouring xylose isomerase in anoxic chemostat culture using non-detoxified pretreatment liquor from triticale straw. RESULTS Following ethyl methanesulfonate (EMS) mutagenesis, Saccharomyces cerevisiae strain D5A⁺ (ATCC 200062 strain platform), harbouring the xylose isomerase (XI) gene for pentose co-fermentation was grown in anoxic chemostat culture for 100 generations at a dilution rate of 0.10 h⁻¹ in a medium consisting of 60% (v/v) non-detoxified hydrolysate liquor from steam-pretreated triticale straw, supplemented with 20 g/L xylose as carbon source. In semi-aerobic batch cultures in the same medium, the isolated strain D5A(+H) exhibited a slightly lower maximum specific growth rate (μ(max) = 0.12 ± 0.01 h⁻¹) than strain TMB3400, with no ethanol production observed by the latter strain. Strain D5A(+H) also exhibited a shorter lag phase (4 h vs. 30 h) and complete removal of HMF, furfural and acetic acid from the fermentation broth within 24 h, reaching an ethanol concentration of 1.54 g/L at a yield (Y(p/s)) of 0.06 g/g xylose and a specific productivity of 2.08 g/gh. Evolutionary engineering profoundly affected the yeast metabolism, given that parental strain D5A+ exhibited an oxidative metabolism on xylose prior to strain development. CONCLUSIONS Physiological adaptations confirm improvements in the resistance to and conversion of inhibitors from pretreatment liquor with simultaneous enhancement of xylose to ethanol fermentation. These data support the sequential application of random mutagenesis followed by continuous culture under simultaneous selective pressure from inhibitors and xylose as primary carbon source.
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Affiliation(s)
- Justin Smith
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - Eugéne van Rensburg
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - Johann F Görgens
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
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Enhanced biofuel production through coupled acetic acid and xylose consumption by engineered yeast. Nat Commun 2014; 4:2580. [PMID: 24105024 DOI: 10.1038/ncomms3580] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 09/09/2013] [Indexed: 12/31/2022] Open
Abstract
The anticipation for substituting conventional fossil fuels with cellulosic biofuels is growing in the face of increasing demand for energy and rising concerns of greenhouse gas emissions. However, commercial production of cellulosic biofuel has been hampered by inefficient fermentation of xylose and the toxicity of acetic acid, which constitute substantial portions of cellulosic biomass. Here we use a redox balancing strategy to enable efficient xylose fermentation and simultaneous in situ detoxification of cellulosic feedstocks. By combining a nicotinamide adenine dinucleotide (NADH)-consuming acetate consumption pathway and an NADH-producing xylose utilization pathway, engineered yeast converts cellulosic sugars and toxic levels of acetate together into ethanol under anaerobic conditions. The results demonstrate a breakthrough in making efficient use of carbon compounds in cellulosic biomass and present an innovative strategy for metabolic engineering whereby an undesirable redox state can be exploited to drive desirable metabolic reactions, even improving productivity and yield.
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Bergdahl B, Gorwa-Grauslund MF, van Niel EWJ. Physiological effects of over-expressing compartment-specific components of the protein folding machinery in xylose-fermenting Saccharomyces cerevisiae. BMC Biotechnol 2014; 14:28. [PMID: 24758421 PMCID: PMC4021093 DOI: 10.1186/1472-6750-14-28] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 04/11/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Efficient utilization of both glucose and xylose is necessary for a competitive ethanol production from lignocellulosic materials. Although many advances have been made in the development of xylose-fermenting strains of Saccharomyces cerevisiae, the productivity remains much lower compared to glucose. Previous transcriptional analyses of recombinant xylose-fermenting strains have mainly focused on central carbon metabolism. Very little attention has been given to other fundamental cellular processes such as the folding of proteins. Analysis of previously measured transcript levels in a recombinant XR/XDH-strain showed a wide down-regulation of genes targeted by the unfolded protein response during xylose fermentation. Under anaerobic conditions the folding of proteins is directly connected with fumarate metabolism and requires two essential enzymes: FADH2-dependent fumarate reductase (FR) and Ero1p. In this study we tested whether these enzymes impair the protein folding process causing the very slow growth of recombinant yeast strains on xylose under anaerobic conditions. RESULTS Four strains over-expressing the cytosolic (FRD1) or mitochondrial (OSM1) FR genes and ERO1 in different combinations were constructed. The growth and fermentation performance was evaluated in defined medium as well as in a complex medium containing glucose and xylose. Over-expression of FRD1, alone or in combination with ERO1, did not have any significant effect on xylose fermentation in any medium used. Over-expression of OSM1, on the other hand, led to a diversion of carbon from glycerol to acetate and a decrease in growth rate by 39% in defined medium and by 25% in complex medium. Combined over-expression of OSM1 and ERO1 led to the same diversion of carbon from glycerol to acetate and had a stronger detrimental effect on the growth in complex medium. CONCLUSIONS Increasing the activities of the FR enzymes and Ero1p is not sufficient to increase the anaerobic growth on xylose. So additional components of the protein folding mechanism that were identified in transcription analysis of UPR related genes may also be limiting. This includes i) the transcription factor encoded by HAC1 ii) the activity of Pdi1p and iii) the requirement of free FAD during anaerobic growth.
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Affiliation(s)
- Basti Bergdahl
- Division of Applied Microbiology, Department of Chemistry, Lund University, P,O, Box 124, Lund SE-22100, Sweden.
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Ran H, Zhang J, Gao Q, Lin Z, Bao J. Analysis of biodegradation performance of furfural and 5-hydroxymethylfurfural by Amorphotheca resinae ZN1. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:51. [PMID: 24708699 PMCID: PMC4101820 DOI: 10.1186/1754-6834-7-51] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 03/07/2014] [Indexed: 05/03/2023]
Abstract
BACKGROUND Furfural and 5-hydroxymethylfurfural (HMF) are the degradation products of lignocellulose during pretreatment operations and significantly inhibit the consequent enzymatic hydrolysis and fermentation processes. The biodetoxification fungus Amorphotheca resinae ZN1 had demonstrated its excellent capacity on degrading lignocellulose derived inhibitors and helped the fermentation processes to achieve high yield of ethanol and biochemicals. Analysis of the biological degradation performance of furfural and HMF by A. resinae ZN1 will provide essential information for their fast and complete removal from the pretreated lignocellulose materials and facilitate the consequent ethanol fermentation. RESULTS The degradation performance of furfural and HMF by A. resinae ZN1 was investigated by capturing intermediate metabolic products at various culture conditions. A. resinae ZN1 converts furfural/HMF into furfuryl/HMF alcohols and furoic/HMF acids simultaneously at aerobic condition, and only the corresponding furfuryl/HMF alcohols are obtained at anaerobic condition. The existence of glucose accelerates the degradation rate of furfural and HMF by A. resinae ZN1 and the cell mass growth rate aerobically. Remarkably, glucose is not consumed before furfural or HMF is degraded to a low threshold concentration. The finding suggests that furfural or HMF has a substrate priority of utilization by A. resinae ZN1 than glucose. This property may help the detoxification of furfural and HMF to be operated without consuming glucose. CONCLUSIONS The biological degradation performance of furfural and HMF by A. resinae ZN1 was investigated experimentally. Oxygen supply is important on the complete biodegradation of furfural and HMF by A. resinae ZN1. Furfural or HMF has the priority of substrate utilization than glucose by A. resinae ZN1. This study provided important information for detoxification enhancement and strain modification.
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Affiliation(s)
- Hong Ran
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jian Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Qiuqiang Gao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Zhanglin Lin
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
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Klimacek M, Kirl E, Krahulec S, Longus K, Novy V, Nidetzky B. Stepwise metabolic adaption from pure metabolization to balanced anaerobic growth on xylose explored for recombinant Saccharomyces cerevisiae. Microb Cell Fact 2014; 13:37. [PMID: 24606998 PMCID: PMC4007572 DOI: 10.1186/1475-2859-13-37] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/28/2014] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND To effectively convert lignocellulosic feedstocks to bio-ethanol anaerobic growth on xylose constitutes an essential trait that Saccharomyces cerevisiae strains normally do not adopt through the selective integration of a xylose assimilation route as the rate of ATP-formation is below energy requirements for cell maintenance (mATP). To enable cell growth extensive evolutionary and/or elaborate rational engineering is required. However the number of available strains meeting demands for process integration are limited. In this work evolutionary engineering in just two stages coupled to strain selection under strict anaerobic conditions was carried out with BP10001 as progenitor. BP10001 is an efficient (Yethanol = 0.35 g/g) but slow (qethanol = 0.05 ± 0.01 g/gBM/h) xylose-metabolizing recombinant strain of Saccharomyces cerevisiae that expresses an optimized yeast-type xylose assimilation pathway. RESULTS BP10001 was adapted in 5 generations to anaerobic growth on xylose by prolonged incubation for 91 days in sealed flasks. Resultant strain IBB10A02 displayed a specific growth rate μ of 0.025 ± 0.002 h-1 but produced large amounts of glycerol and xylitol. In addition growth was strongly impaired at pH below 6.0 and in the presence of weak acids. Using sequential batch selection and IBB10A02 as basis, IBB10B05 was evolved (56 generations). IBB10B05 was capable of fast (μ = 0.056 ± 0.003 h-1; qethanol = 0.28 ± 0.04 g/gBM/h), efficient (Yethanol = 0.35 ± 0.02 g/g), robust and balanced fermentation of xylose. Importantly, IBB10A02 and IBB10B05 displayed a stable phenotype. Unlike BP10001 both strains displayed an unprecedented biphasic formation of glycerol and xylitol along the fermentation time. Transition from a glycerol- to a xylitol-dominated growth phase, probably controlled by CO2/HCO3-, was accompanied by a 2.3-fold increase of mATP while YATP (= 87 ± 7 mmolATP/gBM) remained unaffected. As long as glycerol constituted the main by-product energetics of anaerobic growth on xylose and glucose were almost identical. CONCLUSIONS In just 61 generation IBB10B05, displaying ~530% improved strain fitness, was evolved from BP10001. Its excellent xylose fermentation properties under industrial relevant conditions were proven and rendered it competitive. Based on detailed analysis of growth energetics we showed that mATP was predominantly determined by the type of polyol formed rather than, as previously assumed, substrate-specific.
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Affiliation(s)
- Mario Klimacek
- University of Technology Graz, Institute of Biotechnology and Biochemical Engineering, Petersgasse 12/I, 8010 Graz, Austria.
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Xiao Z, Lu JR. Strategies for enhancing fermentative production of acetoin: A review. Biotechnol Adv 2014; 32:492-503. [DOI: 10.1016/j.biotechadv.2014.01.002] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 12/30/2013] [Accepted: 01/03/2014] [Indexed: 01/09/2023]
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Cao D, Tu M, Xie R, Li J, Wu Y, Adhikari S. Inhibitory activity of carbonyl compounds on alcoholic fermentation by Saccharomyces cerevisiae. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:918-926. [PMID: 24401115 DOI: 10.1021/jf405711f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Aldehydes and acids play important roles in the fermentation inhibition of biomass hydrolysates. A series of carbonyl compounds (vanillin, syringaldehyde, 4-hydroxybenzaldehyde, pyrogallol aldehyde, and o-phthalaldehyde) were used to examine the quantitative structure-inhibitory activity relationship of carbonyl compounds on alcoholic fermentation, based on the glucose consumption rate and the final ethanol yield. It was observed that pyrogallol aldehyde and o-phthalaldehyde (5.0 mM) reduced the initial glucose consumption rate by 60 and 89%, respectively, and also decreased the final ethanol yield by 60 and 99%, respectively. Correlating the molecular descriptors to inhibition efficiency in yeast fermentation revealed a strong relationship between the energy of the lowest unoccupied molecular orbital (ELUMO) of aldehydes and their inhibitory efficiency in fermentation. On the other hand, vanillin, syringaldehyde, and 4-hydroxybenzaldehyde (5.0 mM) increased the final ethanol yields by 11, 4, and 1%, respectively. Addition of vanillin appeared to favor ethanol formation over glycerol formation and decreased the glycerol yield in yeast fermentation. Furthermore, alcohol dehydrogenase (ADH) activity dropped significantly from 3.85 to 2.72, 1.83, 0.46, and 0.11 U/mg at 6 h of fermentation at vanillin concentrations of 0, 2.5, 5.0, 10.0, and 25.0 mM correspondingly. In addition, fermentation inhibition by acetic acid and benzoic acid was pH-dependent. Addition of acetate, benzoate, and potassium chloride increased the glucose consumption rate, likely because the salts enhanced membrane permeability, thus increasing glucose consumption.
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Affiliation(s)
- Dongxu Cao
- Forest Products Laboratory and Center for Bioenergy and Bioproducts, Auburn University , 520 Devall Drive, Auburn, Alabama 36849, United States
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Ask M, Bettiga M, Duraiswamy VR, Olsson L. Pulsed addition of HMF and furfural to batch-grown xylose-utilizing Saccharomyces cerevisiae results in different physiological responses in glucose and xylose consumption phase. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:181. [PMID: 24341320 PMCID: PMC3878631 DOI: 10.1186/1754-6834-6-181] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/29/2013] [Indexed: 05/07/2023]
Abstract
BACKGROUND Pretreatment of lignocellulosic biomass generates a number of undesired degradation products that can inhibit microbial metabolism. Two of these compounds, the furan aldehydes 5-hydroxymethylfurfural (HMF) and 2-furaldehyde (furfural), have been shown to be an impediment for viable ethanol production. In the present study, HMF and furfural were pulse-added during either the glucose or the xylose consumption phase in order to dissect the effects of these inhibitors on energy state, redox metabolism, and gene expression of xylose-consuming Saccharomyces cerevisiae. RESULTS Pulsed addition of 3.9 g L-1 HMF and 1.2 g L-1 furfural during either the glucose or the xylose consumption phase resulted in distinct physiological responses. Addition of furan aldehydes in the glucose consumption phase was followed by a decrease in the specific growth rate and the glycerol yield, whereas the acetate yield increased 7.3-fold, suggesting that NAD(P)H for furan aldehyde conversion was generated by acetate synthesis. No change in the intracellular levels of NAD(P)H was observed 1 hour after pulsing, whereas the intracellular concentration of ATP increased by 58%. An investigation of the response at transcriptional level revealed changes known to be correlated with perturbations in the specific growth rate, such as protein and nucleotide biosynthesis. Addition of furan aldehydes during the xylose consumption phase brought about an increase in the glycerol and acetate yields, whereas the xylitol yield was severely reduced. The intracellular concentrations of NADH and NADPH decreased by 58 and 85%, respectively, hence suggesting that HMF and furfural drained the cells of reducing power. The intracellular concentration of ATP was reduced by 42% 1 hour after pulsing of inhibitors, suggesting that energy-requiring repair or maintenance processes were activated. Transcriptome profiling showed that NADPH-requiring processes such as amino acid biosynthesis and sulfate and nitrogen assimilation were induced 1 hour after pulsing. CONCLUSIONS The redox and energy metabolism were found to be more severely affected after pulsing of furan aldehydes during the xylose consumption phase than during glucose consumption. Conceivably, this discrepancy resulted from the low xylose utilization rate, hence suggesting that xylose metabolism is a feasible target for metabolic engineering of more robust xylose-utilizing yeast strains.
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Affiliation(s)
- Magnus Ask
- Department of Chemical and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, SE-41296, Gothenburg, Sweden
| | - Maurizio Bettiga
- Department of Chemical and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, SE-41296, Gothenburg, Sweden
| | - Varuni Raju Duraiswamy
- Department of Chemical and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, SE-41296, Gothenburg, Sweden
| | - Lisbeth Olsson
- Department of Chemical and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, SE-41296, Gothenburg, Sweden
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Hickert LR, de Souza-Cruz PB, Rosa CA, Ayub MAZ. Simultaneous saccharification and co-fermentation of un-detoxified rice hull hydrolysate by Saccharomyces cerevisiae ICV D254 and Spathaspora arborariae NRRL Y-48658 for the production of ethanol and xylitol. BIORESOURCE TECHNOLOGY 2013; 143:112-116. [PMID: 23792660 DOI: 10.1016/j.biortech.2013.05.123] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 05/29/2013] [Accepted: 05/30/2013] [Indexed: 06/02/2023]
Abstract
Co-fermentation and simultaneous saccharification of rice hull hydrolysate (RHH) were investigated for the production of ethanol and xylitol by Saccharomyces cerevisiae, Spathaspora arborariae, or the combination of both. In bioreactor cultures under oxygen limitation, S. cerevisiae was capable of metabolizing glucose from RHH, which contained small amounts of acetic acid, furfural, and hydroxymethylfurfural, achieving ethanol yields of 0.45 and concentrations of 10.5 g L(-1). In the co-culture of S. cerevisiae and S. arborariae pentoses and hexoses from RHH, were converted to ethanol and xylitol, with yields of 0.48 and 0.39, and concentrations of 11 g L(-1) and 3 g L(-1), respectively. The simultaneous saccharification and co-fermentation using both yeasts produced ethanol and xylitol to final concentrations of 14.5 g L(-1) and 3 g L(-1), respectively. Results showed good prospects to use co-cultures of S. cerevisiae and S. arborariae for the bioconversion of RHH into ethanol and xylitol without further detoxification.
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Affiliation(s)
- Lilian Raquel Hickert
- Biotechnology & Biochemical Engineering Laboratory (BiotecLab), Federal University of Rio Grande do Sul, Av. Bento Gonçalves 9500, P.O. Box 15090, ZC 91501-970 Porto Alegre, RS, Brazil
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