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Shan W, Yan Y, Li Y, Hu W, Chen J. Microbial tolerance engineering for boosting lactic acid production from lignocellulose. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:78. [PMID: 37170163 PMCID: PMC10173534 DOI: 10.1186/s13068-023-02334-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 04/28/2023] [Indexed: 05/13/2023]
Abstract
Lignocellulosic biomass is an attractive non-food feedstock for lactic acid production via microbial conversion due to its abundance and low-price, which can alleviate the conflict with food supplies. However, a variety of inhibitors derived from the biomass pretreatment processes repress microbial growth, decrease feedstock conversion efficiency and increase lactic acid production costs. Microbial tolerance engineering strategies accelerate the conversion of carbohydrates by improving microbial tolerance to toxic inhibitors using pretreated lignocellulose hydrolysate as a feedstock. This review presents the recent significant progress in microbial tolerance engineering to develop robust microbial cell factories with inhibitor tolerance and their application for cellulosic lactic acid production. Moreover, microbial tolerance engineering crosslinking other efficient breeding tools and novel approaches are also deeply discussed, aiming to providing a practical guide for economically viable production of cellulosic lactic acid.
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Affiliation(s)
- Wenwen Shan
- Department of Biophysics, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Yongli Yan
- Department of Biophysics, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Yongda Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, People's Republic of China
| | - Wei Hu
- Department of Biophysics, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, People's Republic of China.
| | - Jihong Chen
- Department of Biophysics, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, People's Republic of China.
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Ndubuisi IA, Amadi CO, Nwagu TN, Murata Y, Ogbonna JC. Non-conventional yeast strains: Unexploited resources for effective commercialization of second generation bioethanol. Biotechnol Adv 2023; 63:108100. [PMID: 36669745 DOI: 10.1016/j.biotechadv.2023.108100] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 01/13/2023] [Accepted: 01/13/2023] [Indexed: 01/18/2023]
Abstract
The conventional yeast (Saccharomyces cerevisiae) is the most studied yeast and has been used in many important industrial productions, especially in bioethanol production from first generation feedstock (sugar and starchy biomass). However, for reduced cost and to avoid competition with food, second generation bioethanol, which is produced from lignocellulosic feedstock, is now being investigated. Production of second generation bioethanol involves pre-treatment and hydrolysis of lignocellulosic biomass to sugar monomers containing, amongst others, d-glucose and D-xylose. Intrinsically, S. cerevisiae strains lack the ability to ferment pentose sugars and genetic engineering of S. cerevisiae to inculcate the ability to ferment pentose sugars is ongoing to develop recombinant strains with the required stability and robustness for commercial second generation bioethanol production. Furthermore, pre-treatment of these lignocellulosic wastes leads to the release of inhibitory compounds which adversely affect the growth and fermentation by S. cerevisae. S. cerevisiae also lacks the ability to grow at high temperatures which favour Simultaneous Saccharification and Fermentation of substrates to bioethanol. There is, therefore, a need for robust yeast species which can co-ferment hexose and pentose sugars and can tolerate high temperatures and the inhibitory substances produced during pre-treatment and hydrolysis of lignocellulosic materials. Non-conventional yeast strains are potential solutions to these problems due to their abilities to ferment both hexose and pentose sugars, and tolerate high temperature and stress conditions encountered during ethanol production from lignocellulosic hydrolysate. This review highlights the limitations of the conventional yeast species and the potentials of non-conventional yeast strains in commercialization of second generation bioethanol.
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Affiliation(s)
| | - Chioma O Amadi
- Department of Microbiology, University of Nigeria Nsukka, Nigeria
| | - Tochukwu N Nwagu
- Department of Microbiology, University of Nigeria Nsukka, Nigeria
| | - Y Murata
- Biological Resources and Post-Harvest Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - James C Ogbonna
- Department of Microbiology, University of Nigeria Nsukka, Nigeria.
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Identification of traits to improve co-assimilation of glucose and xylose by adaptive evolution of Spathaspora passalidarum and Scheffersomyces stipitis yeasts. Appl Microbiol Biotechnol 2023; 107:1143-1157. [PMID: 36625916 DOI: 10.1007/s00253-023-12362-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/21/2022] [Accepted: 12/31/2022] [Indexed: 01/11/2023]
Abstract
Lignocellulosic biomass is a renewable raw material for producing several high-value-added chemicals and fuels. In general, xylose and glucose are the major sugars in biomass hydrolysates, and their efficient utilization by microorganisms is critical for an economical production process. Yeasts capable of co-consuming mixed sugars might lead to higher yields and productivities in industrial fermentation processes. Herein, we performed adaptive evolution assays with two xylose-fermenting yeasts, Spathaspora passalidarum and Scheffersomyces stipitis, to obtain derived clones with improved capabilities of glucose and xylose co-consumption. Adapted strains were obtained after successive growth selection using xylose and the non-metabolized glucose analog 2-deoxy-D-glucose as a selective pressure. The co-fermentation capacity of evolved and parental strains was evaluated on xylose-glucose mixtures. Our results revealed an improved co-assimilation capability by the evolved strains; however, xylose and glucose consumption were observed at slower rates than the parental yeasts. Genome resequencing of the evolved strains revealed genes affected by non-synonymous variants that might be involved with the co-consumption phenotype, including the HXT2.4 gene that encodes a putative glucose transporter in Sp. passalidarum. Expression of this mutant HXT2.4 in Saccharomyces cerevisiae improved the cells' co-assimilation of glucose and xylose. Therefore, our results demonstrated the successful improvement of co-fermentation through evolutionary engineering and the identification of potential targets for further genetic engineering of different yeast strains. KEY POINTS: • Laboratory evolution assay was used to obtain improved sugar co-consumption of non-Saccharomyces strains. • Evolved Sp. passalidarum and Sc. stipitis were able to more efficiently co-ferment glucose and xylose. • A mutant Hxt2.4 permease, which co-transports xylose and glucose, was identified.
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Bisht N, Dalal V, Tewari L. Molecular modeling and dynamics simulation of alcohol dehydrogenase enzyme from high efficacy cellulosic ethanol-producing yeast mutant strain Pichia kudriavzevii BGY1-γm. J Biomol Struct Dyn 2022; 40:12022-12036. [PMID: 34424128 DOI: 10.1080/07391102.2021.1967196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
One of the major constraints limiting the use of abundantly available lignocellulosic biomass as potential feedstock for alcohol industry is the lack of C6/C5 co-sugar fermenting yeast. The present study explores a mutant yeast Pichia kudriavzevii BGY1-γm as a potential strain for bioconversion of glucose/xylose sugars of green biomass into ethanol under batch fermentation. The mutant strain having higher alcohol dehydrogenase activity (11.31%) showed significantly higher ethanol concentration during co-fermentation of glucose/xylose sugars (14.2%) as compared to the native strain. Based on 99% sequence similarity of ADH encoding gene from the mutant with the gene sequences from other yeast strains, the ADH enzyme was identified as ADH-1 type. The study reveals first three-dimensional model of ADH-1 utilizing glucose/xylose sugars from P. kudriavzevii BGY1-γm (PkADH mutant). The refined and validated model of PkADH mutant was used for molecular docking against the substrate (acetaldehyde) and product (ethanol). Molecular docking results showed that substrate and product exhibited a binding affinity of -4.55 and -4.5 kcal/mol with PkADH mutant. Acetaldehyde and ethanol interacted at the active site of PkADH mutant via hydrogen bonds (Ser42, His69 and Asp163) and hydrophobic interactions (Cys40, Ser42, His69, Cys95, Trp123 and Asp163) to form the stable protein-ligand complex. Molecular dynamics analysis revealed that PkADH-mutant acetaldehyde and PkADH-mutant ethanol complexes were more stable than PkADH mutant. MMPBSA binding energy confirmed that binding of substrate and product results in the formation of a lower energy stable protein-ligand complex.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Neha Bisht
- Department of Microbiology, College of Basic Sciences & Humanities, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttrakhand, India
| | - Vikram Dalal
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Lakshmi Tewari
- Department of Microbiology, College of Basic Sciences & Humanities, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttrakhand, India
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Boonchuay P, Techapun C, Leksawasdi N, Seesuriyachan P, Hanmoungjai P, Watanabe M, Srisupa S, Chaiyaso T. Bioethanol Production from Cellulose-Rich Corncob Residue by the Thermotolerant Saccharomyces cerevisiae TC-5. J Fungi (Basel) 2021; 7:547. [PMID: 34356926 PMCID: PMC8305858 DOI: 10.3390/jof7070547] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/05/2021] [Accepted: 07/08/2021] [Indexed: 11/17/2022] Open
Abstract
This study aimed to select thermotolerant yeast for bioethanol production from cellulose-rich corncob (CRC) residue. An effective yeast strain was identified as Saccharomyces cerevisiae TC-5. Bioethanol production from CRC residue via separate hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF), and prehydrolysis-SSF (pre-SSF) using this strain were examined at 35-42 °C compared with the use of commercial S. cerevisiae. Temperatures up to 40 °C did not affect ethanol production by TC-5. The ethanol concentration obtained via the commercial S. cerevisiae decreased with increasing temperatures. The highest bioethanol concentrations obtained via SHF, SSF, and pre-SSF at 35-40 °C of strain TC-5 were not significantly different (20.13-21.64 g/L). The SSF process, with the highest ethanol productivity (0.291 g/L/h), was chosen to study the effect of solid loading at 40 °C. A CRC level of 12.5% (w/v) via fed-batch SSF resulted in the highest ethanol concentrations of 38.23 g/L. Thereafter, bioethanol production via fed-batch SSF with 12.5% (w/v) CRC was performed in 5-L bioreactor. The maximum ethanol concentration and ethanol productivity values were 31.96 g/L and 0.222 g/L/h, respectively. The thermotolerant S. cerevisiae TC-5 is promising yeast for bioethanol production under elevated temperatures via SSF and the use of second-generation substrates.
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Affiliation(s)
- Pinpanit Boonchuay
- Division of Biotechnology, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand; (P.B.); (C.T.); (P.S.); (P.H.); (S.S.)
| | - Charin Techapun
- Division of Biotechnology, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand; (P.B.); (C.T.); (P.S.); (P.H.); (S.S.)
| | - Noppol Leksawasdi
- Division of Food Engineering, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand;
| | - Phisit Seesuriyachan
- Division of Biotechnology, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand; (P.B.); (C.T.); (P.S.); (P.H.); (S.S.)
| | - Prasert Hanmoungjai
- Division of Biotechnology, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand; (P.B.); (C.T.); (P.S.); (P.H.); (S.S.)
| | - Masanori Watanabe
- Department of Food, Life and Environmental Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata 9978555, Japan;
| | - Siraprapa Srisupa
- Division of Biotechnology, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand; (P.B.); (C.T.); (P.S.); (P.H.); (S.S.)
| | - Thanongsak Chaiyaso
- Division of Biotechnology, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand; (P.B.); (C.T.); (P.S.); (P.H.); (S.S.)
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Recovery of saccharides from lignocellulosic hydrolysates using nanofiltration membranes: A review. FOOD AND BIOPRODUCTS PROCESSING 2021. [DOI: 10.1016/j.fbp.2021.01.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
In order to exploit a fast-growing Paulownia hardwood as an energy crop, a xylose-enriched hydrolysate was obtained in this work to increase the ethanol concentration using the hemicellulosic fraction, besides the already widely studied cellulosic fraction. For that, Paulownia elongata x fortunei was submitted to autohydrolysis treatment (210 °C or S0 of 4.08) for the xylan solubilization, mainly as xylooligosaccharides. Afterwards, sequential stages of acid hydrolysis, concentration, and detoxification were evaluated to obtain fermentable sugars. Thus, detoxified and non-detoxified hydrolysates (diluted or not) were fermented for ethanol production using a natural xylose-consuming yeast, Scheffersomyces stipitis CECT 1922, and an industrial Saccharomyces cerevisiae MEC1133 strain, metabolic engineered strain with the xylose reductase/xylitol dehydrogenase pathway. Results from fermentation assays showed that the engineered S. cerevisiae strain produced up to 14.2 g/L of ethanol (corresponding to 0.33 g/g of ethanol yield) using the non-detoxified hydrolysate. Nevertheless, the yeast S. stipitis reached similar values of ethanol, but only in the detoxified hydrolysate. Hence, the fermentation data prove the suitability and robustness of the engineered strain to ferment non-detoxified liquor, and the appropriateness of detoxification of liquor for the use of less robust yeast. In addition, the success of hemicellulose-to-ethanol production obtained in this work shows the Paulownia biomass as a suitable renewable source for ethanol production following a suitable fractionation process within a biorefinery approach.
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Yang Y, Xia Y, Lin X, Wang G, Zhang H, Xiong Z, Yu H, Yu J, Ai L. Improvement of flavor profiles in Chinese rice wine by creating fermenting yeast with superior ethanol tolerance and fermentation activity. Food Res Int 2018; 108:83-92. [PMID: 29735105 DOI: 10.1016/j.foodres.2018.03.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/09/2018] [Accepted: 03/11/2018] [Indexed: 01/18/2023]
Abstract
Producing alcoholic beverages with novel flavor are desirable for winemakers. We created fermenting yeast with superior ethanol tolerance and fermentation activity to improve the flavor profiles of Chinese rice wine. Strategies of ethanol domestication, ultraviolet mutagenesis (UV) and protoplast fusion were conducted to create yeast hybrids with excellent oenological characteristic. The obtained diploid hybrid F23 showed a cell viability of 6.2% under 25% ethanol, whereas its diploid parental strains could not survive under 20% ethanol. During Chinese rice wine-making, compared to diploid parents, F23 produced 7.07%-12.44% higher yield of ethanol. Flavor analysis indicated that the total content of flavor compounds in F23 wine was 19.99-26.55% higher than that of parent wines. Specifically, F23 exhibited higher capacity in producing 2-phenylethanol, short-chain and long-chain fatty-acid ethyl-ester than diploid parents. Compared to diploid parents, F23 introduced more flavor contributors with odor activity values (OAVs) above one to Chinese rice wine, and those contributors were found with higher OAVs. Based on principal component analysis (PCA), the flavor characteristic of F23 wine was similar to each of parent wine. Additionally, sensory evaluation showed that F23 wine was highly assessed for its intensive levels in fruit-aroma, alcohol-aroma and mouthfeel. Hybrid F23 not only displayed superior flavor production and oenological performance in making Chinese rice wine, but also could act as potential "mixed-like" starter to enrich wine style and differentiation.
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Affiliation(s)
- Yijin Yang
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Yongjun Xia
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Xiangna Lin
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Guangqiang Wang
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Hui Zhang
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Zhiqiang Xiong
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Haiyan Yu
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai, 200235, PR China
| | - Jianshen Yu
- Shanghai Jinfeng Wine Co., Ltd., Shanghai, 200120, PR China
| | - Lianzhong Ai
- Shanghai Engineering Research Center of Food Microbiology, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, PR China.
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