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Darvishi F, Rafatiyan S, Abbaspour Motlagh Moghaddam MH, Atkinson E, Ledesma-Amaro R. Applications of synthetic yeast consortia for the production of native and non-native chemicals. Crit Rev Biotechnol 2024; 44:15-30. [PMID: 36130800 DOI: 10.1080/07388551.2022.2118569] [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] [Received: 06/03/2022] [Revised: 08/03/2022] [Accepted: 08/19/2022] [Indexed: 11/03/2022]
Abstract
The application of microbial consortia is a new approach in synthetic biology. Synthetic yeast consortia, simple or complex synthetic mixed cultures, have been used for the production of various metabolites. Cooperation between the members of a consortium and cross-feeding can be applied to create stable microbial communication. These consortia can: consume a variety of substrates, perform more complex functions, produce metabolites in high titer, rate, and yield (TRY), and show higher stability during industrial fermentations. Due to the new research context of synthetic consortia, few yeasts were used to build these consortia, including Saccharomyces cerevisiae, Pichia pastoris, and Yarrowia lipolytica. Here, application of the yeasts for design of synthetic microbial consortia and their advantages and bottlenecks for effective and robust production of valuable metabolites from bioresource, including: cellulose, xylose, glycerol and so on, have been reviewed. Key trends and challenges are also discussed for the future development of synthetic yeast consortia.
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Affiliation(s)
- Farshad Darvishi
- Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran
- Research Center for Applied Microbiology and Microbial Biotechnology (CAMB), Alzahra University, Tehran, Iran
| | - Sajad Rafatiyan
- Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | | | - Eliza Atkinson
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London, UK
| | - Rodrigo Ledesma-Amaro
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London, UK
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2
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Asemoloye MD, Bello TS, Oladoye PO, Remilekun Gbadamosi M, Babarinde SO, Ebenezer Adebami G, Olowe OM, Temporiti MEE, Wanek W, Marchisio MA. Engineered yeasts and lignocellulosic biomaterials: shaping a new dimension for biorefinery and global bioeconomy. Bioengineered 2023; 14:2269328. [PMID: 37850721 PMCID: PMC10586088 DOI: 10.1080/21655979.2023.2269328] [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] [Received: 06/24/2023] [Accepted: 10/03/2023] [Indexed: 10/19/2023] Open
Abstract
The next milestone of synthetic biology research relies on the development of customized microbes for specific industrial purposes. Metabolic pathways of an organism, for example, depict its chemical repertoire and its genetic makeup. If genes controlling such pathways can be identified, scientists can decide to enhance or rewrite them for different purposes depending on the organism and the desired metabolites. The lignocellulosic biorefinery has achieved good progress over the past few years with potential impact on global bioeconomy. This principle aims to produce different bio-based products like biochemical(s) or biofuel(s) from plant biomass under microbial actions. Meanwhile, yeasts have proven very useful for different biotechnological applications. Hence, their potentials in genetic/metabolic engineering can be fully explored for lignocellulosic biorefineries. For instance, the secretion of enzymes above the natural limit (aided by genetic engineering) would speed-up the down-line processes in lignocellulosic biorefineries and the cost. Thus, the next milestone would greatly require the development of synthetic yeasts with much more efficient metabolic capacities to achieve basic requirements for particular biorefinery. This review gave comprehensive overview of lignocellulosic biomaterials and their importance in bioeconomy. Many researchers have demonstrated the engineering of several ligninolytic enzymes in heterologous yeast hosts. However, there are still many factors needing to be well understood like the secretion time, titter value, thermal stability, pH tolerance, and reactivity of the recombinant enzymes. Here, we give a detailed account of the potentials of engineered yeasts being discussed, as well as the constraints associated with their development and applications.
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Affiliation(s)
- Michael Dare Asemoloye
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, Nankai District, China
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Tunde Sheriffdeen Bello
- Department of Plant Biology, School of Life Sciences, Federal University of Technology Minna, Minna Niger State, Nigeria
| | | | | | - Segun Oladiran Babarinde
- Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia, Canada
| | | | - Olumayowa Mary Olowe
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Mail Bag, Mmabatho, South Africa
| | | | - Wolfgang Wanek
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Mario Andrea Marchisio
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, Nankai District, China
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3
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Wright TA, Bennett C, Johnson MR, Fischesser H, Chandrarathne BM, Ram N, Maloof E, Tyler A, Upshaw CR, Stewart JM, Page RC, Konkolewicz D. Investigating the Impact of Polymer Length, Attachment Site, and Charge on Enzymatic Activity and Stability of Cellulase. Biomacromolecules 2022; 23:4097-4109. [PMID: 36130239 DOI: 10.1021/acs.biomac.2c00441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The thermophilic cellulase Cel5a from Fervidobacterium nodosum (FnCel5a) was conjugated with neutral, cationic, and anionic polymers of increasing molecular weights. The enzymatic activity toward an anionic soluble cellulose derivative, thermal stability, and functional chemical stability of these bioconjugates were investigated. The results suggest that increasing polymer chain length for polymers compatible with the substrate enhances the positive impact of polymer conjugation on enzymatic activity. Activity enhancements of nearly 100% were observed for bioconjugates with N,N-dimethyl acrylamide (DMAm) and N,N-dimethyl acrylamide-2-(N,N-dimethylamino)ethyl methacrylate (DMAm/DMAEMA) due to proposed polymer-substrate compatibility enabled by potential noncovalent interactions. Double conjugation of two functionally distinct polymers to wild-type and mutated FnCel5a using two conjugation methods was achieved. These doubly conjugated bioconjugates exhibited similar thermal stability to the unmodified wild-type enzyme, although enzymatic activity initially gained from conjugation was lost, suggesting that chain length may be a better tool for bioconjugate activity modulation than double conjugation.
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Affiliation(s)
- Thaiesha A Wright
- Department of Chemistry and Biochemistry, Miami University, 651 East High Street, Oxford, Ohio 45056 United States
| | - Camaryn Bennett
- Department of Chemistry and Biochemistry, Miami University, 651 East High Street, Oxford, Ohio 45056 United States
| | - Madolynn R Johnson
- Department of Chemistry and Biochemistry, Miami University, 651 East High Street, Oxford, Ohio 45056 United States
| | - Henry Fischesser
- Department of Chemistry and Biochemistry, Miami University, 651 East High Street, Oxford, Ohio 45056 United States
| | | | - Natasha Ram
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 3620, United States
| | - Elias Maloof
- Department of Chemistry and Biochemistry, Miami University, 651 East High Street, Oxford, Ohio 45056 United States
| | - Amoni Tyler
- Department of Agricultural and Life Sciences, Central State University, 1400 Brush Row Road, Wilberforce, Ohio 45384, United States
| | - Chanell R Upshaw
- Department of Chemistry and Biochemistry, Miami University, 651 East High Street, Oxford, Ohio 45056 United States
| | - Jamie M Stewart
- Department of Chemistry and Biochemistry, Miami University, 651 East High Street, Oxford, Ohio 45056 United States
| | - Richard C Page
- Department of Chemistry and Biochemistry, Miami University, 651 East High Street, Oxford, Ohio 45056 United States
| | - Dominik Konkolewicz
- Department of Chemistry and Biochemistry, Miami University, 651 East High Street, Oxford, Ohio 45056 United States
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Wang Y, Wu B, Ma T, Mi Y, Jiang H, Yan H, Zhao P, Zhang S, Wu L, Chen L, Zang H, Li C. Efficient conversion of hemicellulose into 2, 3-butanediol by engineered psychrotrophic Raoultella terrigena: mechanism and efficiency. BIORESOURCE TECHNOLOGY 2022; 359:127453. [PMID: 35700903 DOI: 10.1016/j.biortech.2022.127453] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
Low-temperature biorefineries inhibit the multiplication of undesired microorganisms, improve product purity and reduce economic costs. Herein, to improve the 2,3-butanediol (2,3-BD) bioconversion efficiency from hemicellulose, a psychrotrophic hemicellulose-degrading strain Raoultella terrigena HC6 with high β-xylosidase activity 1520 U/mL was isolated and genetically modified. Xylan (hemicellulose replacement) was depolymerized into xylooligosaccharides (XOS) and xylose by HC6, which were further converted into 2,3-BD. Transcriptomic analysis revealed that β-xylosidase gene (xynB) and xylose isomerase gene (xylA), which are beneficial for increasing the carbon flux from xylan to 2,3-BD, were significantly upregulated 56.9-fold and 234-fold, respectively. A recombinant strain was constructed by overexpressing xynB in HC6, which obtained 0.389 g/g yield of 2,3-BD from hemicellulose extracted from corn straw at 15 °C. This study proposed a promised strategy for the bioconversion of agricultural waste into 2,3-BD at low temperatures and provides a basis for future efforts in the achievement of carbon neutrality.
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Affiliation(s)
- Yue Wang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Bowen Wu
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Tian Ma
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Yaozu Mi
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Hanyi Jiang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Haohao Yan
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Peichao Zhao
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Shuo Zhang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Linxuan Wu
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Lei Chen
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Hailian Zang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Chunyan Li
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China.
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Gronchi N, De Bernardini N, Cripwell RA, Treu L, Campanaro S, Basaglia M, Foulquié-Moreno MR, Thevelein JM, Van Zyl WH, Favaro L, Casella S. Natural Saccharomyces cerevisiae Strain Reveals Peculiar Genomic Traits for Starch-to-Bioethanol Production: the Design of an Amylolytic Consolidated Bioprocessing Yeast. Front Microbiol 2022; 12:768562. [PMID: 35126325 PMCID: PMC8815085 DOI: 10.3389/fmicb.2021.768562] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 12/17/2021] [Indexed: 11/13/2022] Open
Abstract
Natural yeast with superior fermentative traits can serve as a platform for the development of recombinant strains that can be used to improve the sustainability of bioethanol production from starch. This process will benefit from a consolidated bioprocessing (CBP) approach where an engineered strain producing amylases directly converts starch into ethanol. The yeast Saccharomyces cerevisiae L20, previously selected as outperforming the benchmark yeast Ethanol Red, was here subjected to a comparative genomic investigation using a dataset of industrial S. cerevisiae strains. Along with Ethanol Red, strain L20 was then engineered for the expression of α-amylase amyA and glucoamylase glaA genes from Aspergillus tubingensis by employing two different approaches (delta integration and CRISPR/Cas9). A correlation between the number of integrated copies and the hydrolytic abilities of the recombinants was investigated. L20 demonstrated important traits for the construction of a proficient CBP yeast. Despite showing a close relatedness to commercial wine yeast and the benchmark Ethanol Red, a unique profile of gene copy number variations (CNVs) was found in L20, mainly encoding membrane transporters and secretion pathway proteins but also the fermentative metabolism. Moreover, the genome annotation disclosed seven open reading frames (ORFs) in L20 that are absent in the reference S288C genome. Genome engineering was successfully implemented for amylase production. However, with equal amylase gene copies, L20 proved its proficiency as a good enzyme secretor by exhibiting a markedly higher amylolytic activity than Ethanol Red, in compliance to the findings of the genomic exploration. The recombinant L20 dT8 exhibited the highest amylolytic activity and produced more than 4 g/L of ethanol from 2% starch in a CBP setting without the addition of supplementary enzymes. Based on the performance of this strain, an amylase/glucoamylase ratio of 1:2.5 was suggested as baseline for further improvement of the CBP ability. Overall, L20 showed important traits for the future construction of a proficient CBP yeast. As such, this work shows that natural S. cerevisiae strains can be used for the expression of foreign secreted enzymes, paving the way to strain improvement for the starch-to-bioethanol route.
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Affiliation(s)
- Nicoletta Gronchi
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Legnaro, Italy
| | | | - Rosemary A Cripwell
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Laura Treu
- Department of Biology, University of Padua, Padua, Italy
| | | | - Marina Basaglia
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Legnaro, Italy
| | | | - Johan M Thevelein
- Department of Molecular Microbiology, VIB, KU Leuven, Leuven, Belgium
- NovelYeast Bv, Open Bio-Incubator, Erasmus High School, Jette, Belgium
| | - Willem H Van Zyl
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Lorenzo Favaro
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Legnaro, Italy
| | - Sergio Casella
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Legnaro, Italy
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Wei H, Wang W, Knoshaug EP, Chen X, Van Wychen S, Bomble YJ, Himmel ME, Zhang M. Disruption of the Snf1 Gene Enhances Cell Growth and Reduces the Metabolic Burden in Cellulase-Expressing and Lipid-Accumulating Yarrowia lipolytica. Front Microbiol 2022; 12:757741. [PMID: 35003001 PMCID: PMC8733397 DOI: 10.3389/fmicb.2021.757741] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/19/2021] [Indexed: 12/01/2022] Open
Abstract
Yarrowia lipolytica is known to be capable of metabolizing glucose and accumulating lipids intracellularly; however, it lacks the cellulolytic enzymes needed to break down cellulosic biomass directly. To develop Y. lipolytica as a consolidated bioprocessing (CBP) microorganism, we previously expressed the heterologous CBH I, CBH II, and EG II cellulase enzymes both individually and collectively in this microorganism. We concluded that the coexpression of these cellulases resulted in a metabolic drain on the host cells leading to reduced cell growth and lipid accumulation. The current study aims to build a new cellulase coexpressing platform to overcome these hinderances by (1) knocking out the sucrose non-fermenting 1 (Snf1) gene that represses the energetically expensive lipid and protein biosynthesis processes, and (2) knocking in the cellulase cassette fused with the recyclable selection marker URA3 gene in the background of a lipid-accumulating Y. lipolytica strain overexpressing ATP citrate lyase (ACL) and diacylglycerol acyltransferase 1 (DGA1) genes. We have achieved a homologous recombination insertion rate of 58% for integrating the cellulases-URA3 construct at the disrupted Snf1 site in the genome of host cells. Importantly, we observed that the disruption of the Snf1 gene promoted cell growth and lipid accumulation and lowered the cellular saturated fatty acid level and the saturated to unsaturated fatty acid ratio significantly in the transformant YL163t that coexpresses cellulases. The result suggests a lower endoplasmic reticulum stress in YL163t, in comparison with its parent strain Po1g ACL-DGA1. Furthermore, transformant YL163t increased in vitro cellulolytic activity by 30%, whereas the “total in vivo newly formed FAME (fatty acid methyl esters)” increased by 16% in comparison with a random integrative cellulase-expressing Y. lipolytica mutant in the same YNB-Avicel medium. The Snf1 disruption platform demonstrated in this study provides a potent tool for the further development of Y. lipolytica as a robust host for the expression of cellulases and other commercially important proteins.
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Affiliation(s)
- Hui Wei
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Wei Wang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Eric P Knoshaug
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Xiaowen Chen
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Stefanie Van Wychen
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States.,National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Yannick J Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Min Zhang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
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Arrey G, Li G, Murphy R, Guimaraes L, Alizadeh S, Poulsen M, Regenberg B. Isolation, characterization, and genome assembly of Barnettozyma botsteinii sp. nov. and novel strains of Kurtzmaniella quercitrusa isolated from the intestinal tract of the termite Macrotermes bellicosus. G3 (BETHESDA, MD.) 2021; 11:jkab342. [PMID: 34586397 PMCID: PMC8664483 DOI: 10.1093/g3journal/jkab342] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 09/17/2021] [Indexed: 11/12/2022]
Abstract
Bioconversion of hemicelluloses into simpler sugars leads to the production of a significant amount of pentose sugars, such as d-xylose. However, efficient utilization of pentoses by conventional yeast production strains remains challenging. Wild yeast strains can provide new industrially relevant characteristics and efficiently utilize pentose sugars. To explore this strategy, we isolated gut-residing yeasts from the termite Macrotermes bellicosus collected in Comoé National Park, Côte d'Ivoire. The yeasts were classified through their Internal Transcribed Spacer/Large Subunit sequence, and their genomes were sequenced and annotated. We identified a novel yeast species, which we name Barnettozyma botsteinii sp. nov. 1118T (MycoBank: 833563, CBS 16679T and IBT 710) and two new strains of Kurtzmaniella quercitrusa: var. comoensis (CBS 16678, IBT 709) and var. filamentosus (CBS 16680, IBT 711). The two K. quercitrusa strains grow 15% faster on synthetic glucose medium than Saccharomyces cerevisiae CEN.PKT in acidic conditions (pH = 3.2) and both strains grow on d-xylose as the sole carbon source at a rate of 0.35 h-1. At neutral pH, the yeast form of K. quercitrusa var. filamentosus, but not var. comoensis, switched to filamentous growth in a carbon source-dependent manner. Their genomes are 11.0-13.2 Mb in size and contain between 4888 and 5475 predicted genes. Together with closely related species, we did not find any relationship between gene content and ability to grow on xylose. Besides its metabolism, K. quercitrusa var. filamentosus has a large potential as a production organism, because of its capacity to grow at low pH and to undergo a dimorphic shift.
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Affiliation(s)
- Gerard Arrey
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen 1165, Denmark
| | - Guangshuo Li
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen 1165, Denmark
| | - Robert Murphy
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen 1165, Denmark
| | - Leandro Guimaraes
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen 1165, Denmark
| | - Sefa Alizadeh
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen 1165, Denmark
| | - Michael Poulsen
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen 1165, Denmark
| | - Birgitte Regenberg
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen 1165, Denmark
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Utilization of Yeast Waste Fermented Citric Waste as a Protein Source to Replace Soybean Meal and Various Roughage to Concentrate Ratios on In Vitro Rumen Fermentation, Gas Kinetic, and Feed Digestion. FERMENTATION-BASEL 2021. [DOI: 10.3390/fermentation7030120] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The objective of this study was to determine the application of citric waste fermented yeast waste (CWYW) obtained from an agro-industrial by-product as a protein source to replace soybean meal (SBM) in a concentrate diet. We also determined the effect of various roughage to concentrate ratios (R:C) on the gas production kinetics, ruminal characteristics, and in vitro digestibility using an in vitro gas production technique. The experiment design was a 3 × 5 factorial design arranged in a completely randomized design (CRD), with three replicates. There were three R:C ratios (60:40, 50:50, and 40:60) and five replacing SBM with CWYW (SBM:CWYW) ratios (100:0, 75:25, 50:50, 25:75, and 0:100). The CWYW product’s crude protein (CP) content was 535 g/kg dry matter (DM). There was no interaction effect between R:C ratios and SBM:CWYW ratios for all parameters observed (p > 0.05). The SBM:CWYW ratio did not affect the kinetics and the cumulative amount of gas. However, the gas potential extent and cumulative production of gas were increased with the R:C ratio of 40:60, and the values were about 74.9 and 75.0 mL/0.5 g, respectively (p < 0.01). The replacement of SBM by CWYW at up to 75% did not alter in vitro dry matter digestibility (IVDMD), but 100% CWYW replacement significantly reduced (p < 0.05) IVDMD at 24 h of incubation and the mean value. In addition, IVDMD at 12 h and 24 h of incubation and the mean value were significantly increased with the R:C ratio of 40:60 (p < 0.01). The SBM:CWYW ratio did not change the ruminal pH and population of protozoa (p > 0.05). The ruminal pH was reduced at the R:C ratio of 40:60 (p < 0.01), whereas the protozoal population at 4 h was increased (p < 0.05). The SBM:CWYW ratio did not impact the in vitro volatile fatty acid (VFA) profile (p > 0.05). However, the total VFA, and propionate (C3) concentration were significantly increased (p < 0.01) by the R:C ratio of 40:60. In conclusion, the replacement of SBM by 75% CWYW did not show any negative impact on parameters observed, and the R:C ratio of 40:60 enhanced the gas kinetics, digestibility, VFA, and C3 concentration.
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9
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Bacterial valorization of pulp and paper industry process streams and waste. Appl Microbiol Biotechnol 2021; 105:1345-1363. [PMID: 33481067 DOI: 10.1007/s00253-021-11107-2] [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: 09/29/2020] [Revised: 12/28/2020] [Accepted: 01/08/2021] [Indexed: 10/22/2022]
Abstract
The pulp and paper industry is a major source of lignocellulose-containing streams. The components of lignocellulose material are lignin, hemicellulose, and cellulose that may be hydrolyzed into their smaller components and used as feedstocks for valorization efforts. Much of this material is contained in underutilized streams and waste products, such as black liquor, pulp and paper sludge, and wastewater. Bacterial fermentation strategies have suitable potential to upgrade lignocellulosic biomass contained in these streams to value-added chemicals. Bacterial conversion allows for a sustainable and economically feasible approach to valorizing these streams, which can bolster and expand applications of the pulp and paper industry. This review discusses the composition of pulp and paper streams, bacterial isolates from process streams that can be used for lignocellulose biotransformations, and technological approaches for improving valorization efforts. KEY POINTS: • Reviews the conversion of pulp and paper industry waste by bacterial isolates. • Metabolic pathways for the breakdown of lignocellulose components. • Methods for isolating bacteria, determining value-added products, and increasing product yields.
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10
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Alahuhta M, Xu Q, Knoshaug EP, Wang W, Wei H, Amore A, Baker JO, Vander Wall T, Himmel ME, Zhang M. Chimeric cellobiohydrolase I expression, activity, and biochemical properties in three oleaginous yeast. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:6. [PMID: 33407766 PMCID: PMC7789491 DOI: 10.1186/s13068-020-01856-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/10/2020] [Indexed: 05/16/2023]
Abstract
Consolidated bioprocessing using oleaginous yeast is a promising modality for the economic conversion of plant biomass to fuels and chemicals. However, yeast are not known to produce effective biomass degrading enzymes naturally and this trait is essential for efficient consolidated bioprocessing. We expressed a chimeric cellobiohydrolase I gene in three different oleaginous, industrially relevant yeast: Yarrowia lipolytica, Lipomyces starkeyi, and Saccharomyces cerevisiae to study the biochemical and catalytic properties and biomass deconstruction potential of these recombinant enzymes. Our results showed differences in glycosylation, surface charge, thermal and proteolytic stability, and efficacy of biomass digestion. L. starkeyi was shown to be an inferior active cellulase producer compared to both the Y. lipolytica and S. cerevisiae enzymes, whereas the cellulase expressed in S. cerevisiae displayed the lowest activity against dilute-acid-pretreated corn stover. Comparatively, the chimeric cellobiohydrolase I enzyme expressed in Y. lipolytica was found to have a lower extent of glycosylation, better protease stability, and higher activity against dilute-acid-pretreated corn stover.
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Affiliation(s)
- Markus Alahuhta
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.
| | - Qi Xu
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Eric P Knoshaug
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Wei Wang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Hui Wei
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Antonella Amore
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - John O Baker
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Todd Vander Wall
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Min Zhang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.
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11
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Smekenov I, Bakhtambayeva M, Bissenbayev K, Saparbayev M, Taipakova S, Bissenbaev AK. Heterologous secretory expression of β-glucosidase from Thermoascus aurantiacus in industrial Saccharomyces cerevisiae strains. Braz J Microbiol 2019; 51:107-123. [PMID: 31776864 DOI: 10.1007/s42770-019-00192-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 11/14/2019] [Indexed: 10/25/2022] Open
Abstract
The use of plant biomass for biofuel production will require efficient utilization of the sugars in lignocellulose, primarily cellobiose, because it is the major soluble by-product of cellulose and acts as a strong inhibitor, especially for cellobiohydrolase, which plays a key role in cellulose hydrolysis. Commonly used ethanologenic yeast Saccharomyces cerevisiae is unable to utilize cellobiose; accordingly, genetic engineering efforts have been made to transfer β-glucosidase genes enabling cellobiose utilization. Nonetheless, laboratory yeast strains have been employed for most of this research, and such strains may be difficult to use in industrial processes because of their generally weaker resistance to stressors and worse fermenting abilities. The purpose of this study was to engineer industrial yeast strains to ferment cellobiose after stable integration of tabgl1 gene that encodes a β-glucosidase from Thermoascus aurantiacus (TaBgl1). The recombinant S. cerevisiae strains obtained in this study secrete TaBgl1, which can hydrolyze cellobiose and produce ethanol. This study clearly indicates that the extent of glycosylation of secreted TaBgl1 depends from the yeast strains used and is greatly influenced by carbon sources (cellobiose or glucose). The recombinant yeast strains showed high osmotolerance and resistance to various concentrations of ethanol and furfural and to high temperatures. Therefore, these yeast strains are suitable for ethanol production processes with saccharified lignocellulose.
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Affiliation(s)
- Izat Smekenov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040
| | - Marzhan Bakhtambayeva
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040
| | - Kudaybergen Bissenbayev
- Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.,Nazarbayev Intellectual School, Almaty, Kazakhstan, 050044
| | - Murat Saparbayev
- Gustave Roussy Cancer Campus, CNRS UMR8200, Université Paris-Sud, F-94805, Villejuif Cedex, France
| | - Sabira Taipakova
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040
| | - Amangeldy K Bissenbaev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040. .,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan, 050040.
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12
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Green Production and Biotechnological Applications of Cell Wall Lytic Enzymes. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9235012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
: Energy demand is constantly growing, and, nowadays, fossil fuels still play a dominant role in global energy production, despite their negative effects on air pollution and the emission of greenhouse gases, which are the main contributors to global warming. An alternative clean source of energy is represented by the lignocellulose fraction of plant cell walls, the most abundant carbon source on Earth. To obtain biofuels, lignocellulose must be efficiently converted into fermentable sugars. In this regard, the exploitation of cell wall lytic enzymes (CWLEs) produced by lignocellulolytic fungi and bacteria may be considered as an eco-friendly alternative. These organisms evolved to produce a variety of highly specific CWLEs, even if in low amounts. For an industrial use, both the identification of novel CWLEs and the optimization of sustainable CWLE-expressing biofactories are crucial. In this review, we focus on recently reported advances in the heterologous expression of CWLEs from microbial and plant expression systems as well as some of their industrial applications, including the production of biofuels from agricultural feedstock and of value-added compounds from waste materials. Moreover, since heterologous expression of CWLEs may be toxic to plant hosts, genetic strategies aimed in converting such a deleterious effect into a beneficial trait are discussed.
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13
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Banerjee S, Mishra G, Roy A. Metabolic Engineering of Bacteria for Renewable Bioethanol Production from Cellulosic Biomass. BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-019-0134-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Song X, Li Y, Wu Y, Cai M, Liu Q, Gao K, Zhang X, Bai Y, Xu H, Qiao M. Metabolic engineering strategies for improvement of ethanol production in cellulolytic Saccharomyces cerevisiae. FEMS Yeast Res 2019; 18:5071949. [PMID: 30107496 DOI: 10.1093/femsyr/foy090] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/09/2018] [Indexed: 01/31/2023] Open
Abstract
As a traditional ethanol-producing microorganism, Saccharomyces cerevisiae is an ideal host for consolidated bioprocessing. However, expression of heterologous cellulase increases the metabolic burden in yeast, which results in low cellulase activity and poor cellulose degradation efficiency. In this study, cellulase-expressing yeast strains that could efficiently degrade different cellulosic substrates were created by optimizing cellulase ratios through a POT1-mediated δ-integration strategy. Metabolic engineering strategies, including optimization of codon usage, promoter and signal peptide, were also included in this system. We also confirmed that heterologous cellulase expression in cellulosic yeast induced the unfolded protein response. To enhance protein folding capacity, the endoplasmic reticulum chaperone protein BiP and the disulfide isomerase Pdi1p were overexpressed, and the Golgi membrane protein Ca2+/Mn2+ ATPase Pmr1p was disrupted to decrease the glycosylation of cellulase. The resultant strain, SK18-3, could produce 5.4 g L-1 ethanol with carboxymethyl-cellulose. Strain SK12-50 achieved 4.7 g L-1 ethanol production with phosphoric acid swollen cellulose hydrolysis. When Avicel was used as the substrate, 3.8 g L-1 ethanol (75% of the theoretical maximum yield) was produced in SK13-34. This work will significantly increase our knowledge of how to engineer optimal yeast strains for biofuel production from cellulosic biomass.
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Affiliation(s)
- Xiaofei Song
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China
| | - Yuanzi Li
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China
| | - Yuzhen Wu
- Department of Microbiology, College of Life Sciences, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China
| | - Miao Cai
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China
| | - Quanli Liu
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China
| | - Kai Gao
- Tianjin Academy of Environmental Sciences, No. 17 Fukang Road, Nankai District, Tianjin 300071, China
| | - Xiuming Zhang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China
| | - Yanling Bai
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China
| | - Haijin Xu
- Department of Microbiology, College of Life Sciences, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China
| | - Mingqiang Qiao
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China
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15
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Ramos-Martinez EM, Fimognari L, Rasmussen MK, Sakuragi Y. Secretion of Acetylxylan Esterase From Chlamydomonas reinhardtii Enables Utilization of Lignocellulosic Biomass as a Carbon Source. Front Bioeng Biotechnol 2019; 7:35. [PMID: 30873405 PMCID: PMC6403119 DOI: 10.3389/fbioe.2019.00035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 02/08/2019] [Indexed: 11/13/2022] Open
Abstract
Microalgae offer a promising biological platform for sustainable biomanufacturing of a wide range of chemicals, pharmaceuticals, and fuels. The model microalga Chlamydomonas reinhardtii is thus far the most versatile algal chassis for bioengineering and can grow using atmospheric CO2 and organic carbons (e.g., acetate and pure cellulose). Ability to utilize renewable feedstock like lignocellulosic biomass as a carbon source could significantly accelerate microalgae-based productions, but this is yet to be demonstrated. We observed that C. reinhardtii was not able to heterotrophically grow using wheat straw, a common type of lignocellulosic biomass, likely due to the recalcitrant nature of the biomass. When the biomass was pretreated with alkaline, C. reinhardtii was able to grow using acetate that was released from the biomass. To establish an eco-friendly and self-sustained growth system, we engineered C. reinhardtii to secrete a fungal acetylxylan esterase (AXE) for hydrolysis of acetylesters in the lignocellulosic biomass. Two transgenic strains (CrAXE03 and CrAXE23) secreting an active AXE into culture media were isolated. Incubation of CrAXE03 with wheat straw resulted in an eight-fold increase in the algal cell counts with a concomitant decrease of biomass acetylester contents by 96%. The transgenic lines showed minor growth defects compared to the parental strain, indicating that secretion of the AXE protein imposes limited metabolic burden. The results presented here would open new opportunities for applying low-cost renewable feedstock, available in large amounts as agricultural and manufacturing by-products, for microalgal cultivation. Furthermore, acetylesters and acetate released from them, are well-known inhibitors in lignocellulosic biofuel productions; thus, direct application of the bioengineered microalga could be exploited for improving renewable biofuel productions.
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Affiliation(s)
| | | | | | - Yumiko Sakuragi
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
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16
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Heterologous co-expression of two β-glucanases and a cellobiose phosphorylase resulted in a significant increase in the cellulolytic activity of the Caldicellulosiruptor bescii exoproteome. J Ind Microbiol Biotechnol 2019; 46:687-695. [PMID: 30783893 DOI: 10.1007/s10295-019-02150-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 02/12/2019] [Indexed: 12/20/2022]
Abstract
The ability to deconstruct plant biomass without conventional pretreatment has made members of the genus Caldicellulosiruptor the target of investigation for the consolidated processing of plant lignocellulosic biomass to biofuels and bioproducts. To investigate the synergy of enzymes involved and to further improve the ability of C. bescii to degrade cellulose, we introduced CAZymes that act synergistically with the C. bescii exoproteome in vivo and in vitro. We recently demonstrated that the Acidothermus cellulolyticus E1 endo-1,4-β-D-glucanase (GH5) with a family 2 carbohydrate-binding module (CBM) increased the activity of C. bescii exoproteome on biomass, presumably acting in concert with CelA. The β-glucanase, GuxA, from A. cellulolyticus is a multi-domain enzyme with strong processive exoglucanase activity, and the cellobiose phosphorylase from Thermotoga maritima catalyzes cellulose degradation acting synergistically with cellobiohydrolases and endoglucanases. We identified new chromosomal insertion sites to co-express these enzymes and the resulting strain showed a significant increase in the enzymatic activity of the exoproteome.
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17
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Wei H, Wang W, Alper HS, Xu Q, Knoshaug EP, Van Wychen S, Lin CY, Luo Y, Decker SR, Himmel ME, Zhang M. Ameliorating the Metabolic Burden of the Co-expression of Secreted Fungal Cellulases in a High Lipid-Accumulating Yarrowia lipolytica Strain by Medium C/N Ratio and a Chemical Chaperone. Front Microbiol 2019; 9:3276. [PMID: 30687267 PMCID: PMC6333634 DOI: 10.3389/fmicb.2018.03276] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/17/2018] [Indexed: 12/19/2022] Open
Abstract
Yarrowia lipolytica, known to accumulate lipids intracellularly, lacks the cellulolytic enzymes needed to break down solid biomass directly. This study aimed to evaluate the potential metabolic burden of expressing core cellulolytic enzymes in an engineered high lipid-accumulating strain of Y. lipolytica. Three fungal cellulases, Talaromyces emersonii-Trichoderma reesei chimeric cellobiohydrolase I (chimeric-CBH I), T. reesei cellobiohydrolase II (CBH II), and T. reesei endoglucanase II (EG II) were expressed using three constitutive strong promoters as a single integrative expression block in a recently engineered lipid hyper-accumulating strain of Y. lipolytica (HA1). In yeast extract-peptone-dextrose (YPD) medium, the resulting cellulase co-expressing transformant YL165-1 had the chimeric-CBH I, CBH II, and EG II secretion titers being 26, 17, and 132 mg L-1, respectively. Cellulase co-expression in YL165-1 in culture media with a moderate C/N ratio of ∼4.5 unexpectedly resulted in a nearly two-fold reduction in cellular lipid accumulation compared to the parental control strain, a sign of cellular metabolic drain. Such metabolic drain was ameliorated when grown in media with a high C/N ratio of 59 having a higher glucose utilization rate that led to approximately twofold more cell mass and threefold more lipid production per liter culture compared to parental control strain, suggesting cross-talk between cellulase and lipid production, both of which involve the endoplasmic reticulum (ER). Most importantly, we found that the chemical chaperone, trimethylamine N-oxide dihydride increased glucose utilization, cell mass and total lipid titer in the transformants, suggesting further amelioration of the metabolic drain. This is the first study examining lipid production in cellulase-expressing Y. lipolytica strains under various C/N ratio media and with a chemical chaperone highlighting the metabolic complexity for developing robust, cellulolytic and lipogenic yeast strains.
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Affiliation(s)
- Hui Wei
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Wei Wang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Hal S Alper
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Qi Xu
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Eric P Knoshaug
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Stefanie Van Wychen
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States.,National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Chien-Yuan Lin
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Yonghua Luo
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Stephen R Decker
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Min Zhang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States.,National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
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18
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Benedetti M, Vecchi V, Barera S, Dall’Osto L. Biomass from microalgae: the potential of domestication towards sustainable biofactories. Microb Cell Fact 2018; 17:173. [PMID: 30414618 PMCID: PMC6230293 DOI: 10.1186/s12934-018-1019-3] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 10/31/2018] [Indexed: 12/22/2022] Open
Abstract
Interest in bulk biomass from microalgae, for the extraction of high-value nutraceuticals, bio-products, animal feed and as a source of renewable fuels, is high. Advantages of microalgal vs. plant biomass production include higher yield, use of non-arable land, recovery of nutrients from wastewater, efficient carbon capture and faster development of new domesticated strains. Moreover, adaptation to a wide range of environmental conditions evolved a great genetic diversity within this polyphyletic group, making microalgae a rich source of interesting and useful metabolites. Microalgae have the potential to satisfy many global demands; however, realization of this potential requires a decrease of the current production costs. Average productivity of the most common industrial strains is far lower than maximal theoretical estimations, suggesting that identification of factors limiting biomass yield and removing bottlenecks are pivotal in domestication strategies aimed to make algal-derived bio-products profitable on the industrial scale. In particular, the light-to-biomass conversion efficiency represents a major constraint to finally fill the gap between theoretical and industrial productivity. In this respect, recent results suggest that significant yield enhancement is feasible. Full realization of this potential requires further advances in cultivation techniques, together with genetic manipulation of both algal physiology and metabolic networks, to maximize the efficiency with which solar energy is converted into biomass and bio-products. In this review, we draft the molecular events of photosynthesis which regulate the conversion of light into biomass, and discuss how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. We outline major successes reached, and promising strategies to achieving significant contributions to future microalgae-based biotechnology.
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Affiliation(s)
- Manuel Benedetti
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Valeria Vecchi
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Simone Barera
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Luca Dall’Osto
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
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19
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Tabañag IDF, Chu IM, Wei YH, Tsai SL. Ethanol production from hemicellulose by a consortium of different genetically-modified sacharomyces cerevisiae. J Taiwan Inst Chem Eng 2018. [DOI: 10.1016/j.jtice.2018.04.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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20
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Genome-centric view of carbon processing in thawing permafrost. Nature 2018; 560:49-54. [PMID: 30013118 DOI: 10.1038/s41586-018-0338-1] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 06/05/2018] [Indexed: 11/09/2022]
Abstract
As global temperatures rise, large amounts of carbon sequestered in permafrost are becoming available for microbial degradation. Accurate prediction of carbon gas emissions from thawing permafrost is limited by our understanding of these microbial communities. Here we use metagenomic sequencing of 214 samples from a permafrost thaw gradient to recover 1,529 metagenome-assembled genomes, including many from phyla with poor genomic representation. These genomes reflect the diversity of this complex ecosystem, with genus-level representatives for more than sixty per cent of the community. Meta-omic analysis revealed key populations involved in the degradation of organic matter, including bacteria whose genomes encode a previously undescribed fungal pathway for xylose degradation. Microbial and geochemical data highlight lineages that correlate with the production of greenhouse gases and indicate novel syntrophic relationships. Our findings link changing biogeochemistry to specific microbial lineages involved in carbon processing, and provide key information for predicting the effects of climate change on permafrost systems.
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21
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Robak K, Balcerek M. Review of Second Generation Bioethanol Production from Residual Biomass. Food Technol Biotechnol 2018; 56:174-187. [PMID: 30228792 PMCID: PMC6117988 DOI: 10.17113/ftb.56.02.18.5428] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 01/11/2018] [Indexed: 11/12/2022] Open
Abstract
In the context of climate change and the depletion of fossil fuels, there is a great need for alternatives to petroleum in the transport sector. This review provides an overview of the production of second generation bioethanol, which is distinguished from the first generation and subsequent generations of biofuels by its use of lignocellulosic biomass as raw material. The structural components of the lignocellulosic biomass such as cellulose, hemicellulose and lignin, are presented along with technological unit steps including pretreatment, enzymatic hydrolysis, fermentation, distillation and dehydration. The purpose of the pretreatment step is to increase the surface area of carbohydrate available for enzymatic saccharification, while minimizing the content of inhibitors. Performing the enzymatic hydrolysis releases fermentable sugars, which are converted by microbial catalysts into ethanol. The hydrolysates obtained after the pretreatment and enzymatic hydrolysis contain a wide spectrum of sugars, predominantly glucose and xylose. Genetically engineered microorganisms are therefore needed to carry out co-fermentation. The excess of harmful inhibitors in the hydrolysate, such as weak organic acids, furan derivatives and phenol components, can be removed by detoxification before fermentation. Effective saccharification further requires using exogenous hemicellulases and cellulolytic enzymes. Conventional species of distiller's yeast are unable to ferment pentoses into ethanol, and only a very few natural microorganisms, including yeast species like Candida shehatae, Pichia (Scheffersomyces) stipitis, and Pachysolen tannophilus, metabolize xylose to ethanol. Enzymatic hydrolysis and fermentation can be performed in a number of ways: by separate saccharification and fermentation, simultaneous saccharification and fermentation or consolidated bioprocessing. Pentose-fermenting microorganisms can be obtained through genetic engineering, by introducing xylose-encoding genes into metabolism of a selected microorganism to optimize its use of xylose accumulated in the hydrolysate.
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Affiliation(s)
- Katarzyna Robak
- Lodz University of Technology, Faculty of Biotechnology and Food Sciences, Institute of Fermentation Technology and Microbiology, Department of Spirit and Yeast Technology, Wolczanska 171/173, PL 90-924 Lodz, Poland
| | - Maria Balcerek
- Lodz University of Technology, Faculty of Biotechnology and Food Sciences, Institute of Fermentation Technology and Microbiology, Department of Spirit and Yeast Technology, Wolczanska 171/173, PL 90-924 Lodz, Poland
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22
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Chaturvedi S, Kumari A, Nain L, Khare SK. Bioprospecting microbes for single-cell oil production from starchy wastes. Prep Biochem Biotechnol 2018; 48:296-302. [DOI: 10.1080/10826068.2018.1431783] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Shivani Chaturvedi
- Enzyme and Microbial Biochemistry Lab, Department of Chemistry, Indian institute of Technology, Delhi, India
| | - Arti Kumari
- Enzyme and Microbial Biochemistry Lab, Department of Chemistry, Indian institute of Technology, Delhi, India
| | - Lata Nain
- Division of Microbiology, ICAR- Indian Agricultural Research Institute, New Delhi, India
| | - Sunil K. Khare
- Enzyme and Microbial Biochemistry Lab, Department of Chemistry, Indian institute of Technology, Delhi, India
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23
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The Role of Yeast-Surface-Display Techniques in Creating Biocatalysts for Consolidated BioProcessing. Catalysts 2018. [DOI: 10.3390/catal8030094] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Climate change is directly linked to the rapid depletion of our non-renewable fossil resources and has posed concerns on sustainability. Thus, imploring the need for us to shift from our fossil based economy to a sustainable bioeconomy centered on biomass utilization. The efficient bioconversion of lignocellulosic biomass (an ideal feedstock) to a platform chemical, such as bioethanol, can be achieved via the consolidated bioprocessing technology, termed yeast surface engineering, to produce yeasts that are capable of this feat. This approach has various strategies that involve the display of enzymes on the surface of yeast to degrade the lignocellulosic biomass, then metabolically convert the degraded sugars directly into ethanol, thus elevating the status of yeast from an immobilization material to a whole-cell biocatalyst. The performance of the engineered strains developed from these strategies are presented, visualized, and compared in this article to highlight the role of this technology in moving forward to our quest against climate change. Furthermore, the qualitative assessment synthesized in this work can serve as a reference material on addressing the areas of improvement of the field and on assessing the capability and potential of the different yeast surface display strategies on the efficient degradation, utilization, and ethanol production from lignocellulosic biomass.
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24
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Xylose transport in yeast for lignocellulosic ethanol production: Current status. J Biosci Bioeng 2017; 125:259-267. [PMID: 29196106 DOI: 10.1016/j.jbiosc.2017.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/07/2017] [Accepted: 10/10/2017] [Indexed: 01/07/2023]
Abstract
Lignocellulosic ethanol has been considered as an alternative transportation fuel. Utilization of hemicellulosic fraction in lignocelluloses is crucial in economical production of lignocellulosic ethanol. However, this fraction has not efficiently been utilized by traditional yeast Saccharomyces cerevisiae. Genetically modified S. cerevisiae, which can utilize xylose, has several limitations including low ethanol yield, redox imbalance, and undesired metabolite formation similar to native xylose utilizing yeasts. Besides, xylose uptake is a major issue, where sugar transport system plays an important role. These genetically modified and wild-type yeast strains have further been engineered for improved xylose uptake. Various techniques have been employed to facilitate the xylose transportation in these strains. The present review is focused on the sugar transport machineries, mechanisms of xylose transport, limitations and how to deal with xylose transport for xylose assimilation in yeast cells. The recent advances in different techniques to facilitate the xylose transportation have also been discussed.
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25
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Xie D. Integrating Cellular and Bioprocess Engineering in the Non-Conventional Yeast Yarrowia lipolytica for Biodiesel Production: A Review. Front Bioeng Biotechnol 2017; 5:65. [PMID: 29090211 PMCID: PMC5650997 DOI: 10.3389/fbioe.2017.00065] [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: 08/31/2017] [Accepted: 10/02/2017] [Indexed: 12/14/2022] Open
Abstract
As one of the major biofuels to replace fossil fuel, biodiesel has now attracted more and more attention due to its advantages in higher energy density and overall less greenhouse gas generation. Biodiesel (fatty acid alkyl esters) is produced by chemically or enzymatically catalyzed transesterification of lipids from microbial cells, microalgae, oil crops, or animal fats. Currently, plant oils or waste cooking oils/fats remain the major source for biodiesel production via enzymatic route, but the production capacity is limited either by the uncertain supplement of plant oils or by the low or inconsistent quality of waste oils/fats. In the past decades, significant progresses have been made on synthesis of microalgae oils directly from CO2via a photosynthesis process, but the production cost from any current technologies is still too high to be commercialized due to microalgae’s slow growth rate on CO2, inefficiency in photo-bioreactors, lack of efficient contamination control methods, and high cost in downstream recovery. At the same time, many oleaginous microorganisms have been studied to produce lipids via the fatty acid synthesis pathway under aerobic fermentation conditions, among them one of the most studied is the non-conventional yeast, Yarrowia lipolytica, which is able to produce fatty acids at very high titer, rate, and yield from various economical substrates. This review summarizes the recent research progresses in both cellular and bioprocess engineering in Y. lipolytica to produce lipids at a low cost that may lead to commercial-scale biodiesel production. Specific technologies include the strain engineering for using various substrates, metabolic engineering in high-yield lipid synthesis, cell morphology study for efficient substrate uptake and product formation, free fatty acid formation and secretion for improved downstream recovery, and fermentation engineering for higher productivities and less operating cost. To further improve the economics of the microbial oil-based biodiesel, production of lipid-related or -derived high-value products are also discussed.
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Affiliation(s)
- Dongming Xie
- Massachusetts Biomanufacturing Center, Department of Chemical Engineering, University of Massachusetts Lowell, Lowell, MA, United States
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Autotransporter-Based Surface Display of Hemicellulases onPseudomonas putida: Whole-Cell Biocatalysts for the Degradation of Biomass. ChemCatChem 2017. [DOI: 10.1002/cctc.201700577] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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27
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Wright TA, Lucius Dougherty M, Schmitz B, Burridge KM, Makaroff K, Stewart JM, Fischesser HD, Shepherd JT, Berberich JA, Konkolewicz D, Page RC. Polymer Conjugation to Enhance Cellulase Activity and Preserve Thermal and Functional Stability. Bioconjug Chem 2017; 28:2638-2645. [DOI: 10.1021/acs.bioconjchem.7b00518] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Thaiesha A. Wright
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Melissa Lucius Dougherty
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Benjamin Schmitz
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Kevin M. Burridge
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Katherine Makaroff
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Jamie M. Stewart
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Henry D. Fischesser
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Jerry T. Shepherd
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Jason A. Berberich
- Department
of Chemical, Paper, and Biomedical Engineering, 650 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Dominik Konkolewicz
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
| | - Richard C. Page
- Department
of Chemistry and Biochemistry, 651 East High Street, Miami University, Oxford, Ohio 45056 United States
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Wickramasinghe GHIM, Rathnayake PPAMSI, Chandrasekharan NV, Weerasinghe MSS, Wijesundera RLC, Wijesundera WSS. Trichoderma virens β-glucosidase I (BGLI) gene; expression in Saccharomyces cerevisiae including docking and molecular dynamics studies. BMC Microbiol 2017; 17:137. [PMID: 28637443 PMCID: PMC5480148 DOI: 10.1186/s12866-017-1049-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 06/14/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Cellulose, a linear polymer of β 1-4, linked glucose, is the most abundant renewable fraction of plant biomass (lignocellulose). It is synergistically converted to glucose by endoglucanase (EG) cellobiohydrolase (CBH) and β-glucosidase (BGL) of the cellulase complex. BGL plays a major role in the conversion of randomly cleaved cellooligosaccharides into glucose. As it is well known, Saccharomyces cerevisiae can efficiently convert glucose into ethanol under anaerobic conditions. Therefore, S.cerevisiae was genetically modified with the objective of heterologous extracellular expression of the BGLI gene of Trichoderma virens making it capable of utilizing cellobiose to produce ethanol. RESULTS The cDNA and a genomic sequence of the BGLI gene of Trichoderma virens was cloned in the yeast expression vector pGAPZα and separately transformed to Saccharomyces cerevisiae. The size of the BGLI cDNA clone was 1363 bp and the genomic DNA clone contained an additional 76 bp single intron following the first exon. The gene was 90% similar to the DNA sequence and 99% similar to the deduced amino acid sequence of 1,4-β-D-glucosidase of T. atroviride (AC237343.1). The BGLI activity expressed by the recombinant genomic clone was 3.4 times greater (1.7 x 10-3 IU ml-1) than that observed for the cDNA clone (5 x 10-4 IU ml-1). Furthermore, the activity was similar to the activity of locally isolated Trichoderma virens (1.5 x 10-3 IU ml-1). The estimated size of the protein was 52 kDA. In fermentation studies, the maximum ethanol production by the genomic and the cDNA clones were 0.36 g and 0.06 g /g of cellobiose respectively. Molecular docking results indicated that the bare protein and cellobiose-protein complex behave in a similar manner with considerable stability in aqueous medium. The deduced binding site and the binding affinity of the constructed homology model appeared to be reasonable. Moreover, it was identified that the five hydrogen bonds formed between the amino acid residues of BGLI and cellobiose are mainly involved in the integrity of enzyme-substrate association. CONCLUSIONS The BGLI activity was remarkably higher in the genomic DNA clone compared to the cDNA clone. Cellobiose was successfully fermented into ethanol by the recombinant S.cerevisiae genomic DNA clone. It has the potential to be used in the industrial production of ethanol as it is capable of simultaneous saccharification and fermentation of cellobiose. Homology modeling, docking studies and molecular dynamics simulation studies will provide a realistic model for further studies in the modification of active site residues which could be followed by mutation studies to improve the catalytic action of BGLI.
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Diethard M, Gasser B, Egermeier M, Marx H, Sauer M. Industrial Microorganisms: Saccharomyces cerevisiaeand other Yeasts. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1002/9783527807796.ch18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Mattanovich Diethard
- BOKU - University of Natural Resources and Life Sciences; Department of Biotechnology; Muthgasse 18 1190 Vienna Austria
- Austrian Centre of Industrial Biotechnology (ACIB GmbH); Muthgasse 18 1190 Vienna Austria
| | - Brigitte Gasser
- BOKU - University of Natural Resources and Life Sciences; Department of Biotechnology; Muthgasse 18 1190 Vienna Austria
- Austrian Centre of Industrial Biotechnology (ACIB GmbH); Muthgasse 18 1190 Vienna Austria
| | - Michael Egermeier
- BOKU - University of Natural Resources and Life Sciences; Department of Biotechnology; Muthgasse 18 1190 Vienna Austria
- BOKU - University of Natural Resources and Life Sciences; CD-Laboratory for Biotechnology of Glycerol; Muthgasse 18 1190 Vienna Austria
| | - Hans Marx
- BOKU - University of Natural Resources and Life Sciences; Department of Biotechnology; Muthgasse 18 1190 Vienna Austria
| | - Michael Sauer
- BOKU - University of Natural Resources and Life Sciences; Department of Biotechnology; Muthgasse 18 1190 Vienna Austria
- Austrian Centre of Industrial Biotechnology (ACIB GmbH); Muthgasse 18 1190 Vienna Austria
- BOKU - University of Natural Resources and Life Sciences; CD-Laboratory for Biotechnology of Glycerol; Muthgasse 18 1190 Vienna Austria
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Yang S, Fei Q, Zhang Y, Contreras LM, Utturkar SM, Brown SD, Himmel ME, Zhang M. Zymomonas mobilis as a model system for production of biofuels and biochemicals. Microb Biotechnol 2016; 9:699-717. [PMID: 27629544 PMCID: PMC5072187 DOI: 10.1111/1751-7915.12408] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/03/2016] [Accepted: 08/05/2016] [Indexed: 12/04/2022] Open
Abstract
Zymomonas mobilis is a natural ethanologen with many desirable industrial biocatalyst characteristics. In this review, we will discuss work to develop Z. mobilis as a model system for biofuel production from the perspectives of substrate utilization, development for industrial robustness, potential product spectrum, strain evaluation and fermentation strategies. This review also encompasses perspectives related to classical genetic tools and emerging technologies in this context.
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Affiliation(s)
- Shihui Yang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA. .,Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, 430062, China.
| | - Qiang Fei
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.,School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Yaoping Zhang
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin, Madison, WI, 53726, USA
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, University of Texas, Austin, TX, 78712, USA
| | - Sagar M Utturkar
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37919, USA
| | - Steven D Brown
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37919, USA.,BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Min Zhang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.
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31
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Coudreuse D. Insights from synthetic yeasts. Yeast 2016; 33:483-92. [PMID: 27145443 DOI: 10.1002/yea.3169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/08/2016] [Accepted: 04/12/2016] [Indexed: 12/17/2022] Open
Abstract
Synthetic biology is one of the most exciting strategies for the investigation of living organisms and lies at the intersection of biology and engineering. Originally developed in prokaryotes, the idea of deciphering biological phenomena through building artificial genetic circuits and studying their behaviours has rapidly demonstrated its potential in a broad range of fields in the life sciences. From the assembly of synthetic genomes to the generation of novel biological functions, yeast cells have imposed themselves as the most powerful eukaryotic model for this approach. However, we are only beginning to explore the possibilities of synthetic biology, and the perspectives it offers in a genetically amenable system such as yeasts are endless. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Damien Coudreuse
- SyntheCell Team, Institute of Genetics and Development of Rennes, CNRS UMR, 6290, Rennes, France
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33
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Hu ML, Zha J, He LW, Lv YJ, Shen MH, Zhong C, Li BZ, Yuan YJ. Enhanced Bioconversion of Cellobiose by Industrial Saccharomyces cerevisiae Used for Cellulose Utilization. Front Microbiol 2016; 7:241. [PMID: 26973619 PMCID: PMC4776165 DOI: 10.3389/fmicb.2016.00241] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 02/15/2016] [Indexed: 01/26/2023] Open
Abstract
Cellobiose accumulation and the compromised temperature for yeast fermentation are the main limiting factors of enzymatic hydrolysis process during simultaneous saccharification and fermentation (SSF). In this study, genes encoding cellobiose transporter and β-glucosidase were introduced into an industrial Saccharomyces cerevisiae strain, and evolution engineering was carried out to improve the cellobiose utilization of the engineered yeast strain. The evolved strain exhibited significantly higher cellobiose consumption rate (2.8-fold) and ethanol productivity (4.9-fold) compared with its parent strain. Besides, the evolved strain showed a high cellobiose consumption rate of 3.67 g/L/h at 34°C and 3.04 g/L/h at 38°C. Moreover, little cellobiose was accumulated during SSF of Avicel using the evolved strain at 38°C, and the ethanol yield from Avicel increased by 23% from 0.34 to 0.42 g ethanol/g cellulose. Overexpression of the genes encoding cellobiose transporter and β-glucosidase accelerated cellobiose utilization, and the improvement depended on the strain background. The results proved that fast cellobiose utilization enhanced ethanol production by reducing cellobiose accumulation during SSF at high temperature.
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Affiliation(s)
- Meng-Long Hu
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China
| | - Jian Zha
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China
| | - Lin-Wei He
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China
| | - Ya-Jin Lv
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China
| | - Ming-Hua Shen
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China
| | - Cheng Zhong
- Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science and Technology Tianjin, China
| | - Bing-Zhi Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China
| | - Ying-Jin Yuan
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China
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Unveiling the metabolic potential of two soil-derived microbial consortia selected on wheat straw. Sci Rep 2015; 5:13845. [PMID: 26343383 PMCID: PMC4561380 DOI: 10.1038/srep13845] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 08/07/2015] [Indexed: 12/21/2022] Open
Abstract
Based on the premise that plant biomass can be efficiently degraded by mixed microbial cultures and/or enzymes, we here applied a targeted metagenomics-based approach to explore the metabolic potential of two forest soil-derived lignocellulolytic microbial consortia, denoted RWS and TWS (bred on wheat straw). Using the metagenomes of three selected batches of two experimental systems, about 1.2 Gb of sequence was generated. Comparative analyses revealed an overrepresentation of predicted carbohydrate transporters (ABC, TonB and phosphotransferases), two-component sensing systems and β-glucosidases/galactosidases in the two consortia as compared to the forest soil inoculum. Additionally, “profiling” of carbohydrate-active enzymes showed significant enrichments of several genes encoding glycosyl hydrolases of families GH2, GH43, GH92 and GH95. Sequence analyses revealed these to be most strongly affiliated to genes present on the genomes of Sphingobacterium, Bacteroides, Flavobacterium and Pedobacter spp. Assembly of the RWS and TWS metagenomes generated 16,536 and 15,902 contigs of ≥10 Kb, respectively. Thirteen contigs, containing 39 glycosyl hydrolase genes, constitute novel (hemi)cellulose utilization loci with affiliation to sequences primarily found in the Bacteroidetes. Overall, this study provides deep insight in the plant polysaccharide degrading capabilities of microbial consortia bred from forest soil, highlighting their biotechnological potential.
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Petrovič U. Next-generation biofuels: a new challenge for yeast. Yeast 2015; 32:583-93. [DOI: 10.1002/yea.3082] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/16/2015] [Accepted: 06/16/2015] [Indexed: 11/11/2022] Open
Affiliation(s)
- Uroš Petrovič
- Jožef Stefan Institute; Department of Molecular and Biomedical Sciences; Ljubljana Slovenia
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36
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Kavšček M, Stražar M, Curk T, Natter K, Petrovič U. Yeast as a cell factory: current state and perspectives. Microb Cell Fact 2015; 14:94. [PMID: 26122609 PMCID: PMC4486425 DOI: 10.1186/s12934-015-0281-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 06/11/2015] [Indexed: 02/06/2023] Open
Abstract
The yeast Saccharomyces cerevisiae is one of the oldest and most frequently used microorganisms in biotechnology with successful applications in the production of both bulk and fine chemicals. Yet, yeast researchers are faced with the challenge to further its transition from the old workhorse to a modern cell factory, fulfilling the requirements for next generation bioprocesses. Many of the principles and tools that are applied for this development originate from the field of synthetic biology and the engineered strains will indeed be synthetic organisms. We provide an overview of the most important aspects of this transition and highlight achievements in recent years as well as trends in which yeast currently lags behind. These aspects include: the enhancement of the substrate spectrum of yeast, with the focus on the efficient utilization of renewable feedstocks, the enhancement of the product spectrum through generation of independent circuits for the maintenance of redox balances and biosynthesis of common carbon building blocks, the requirement for accurate pathway control with improved genome editing and through orthogonal promoters, and improvement of the tolerance of yeast for specific stress conditions. The causative genetic elements for the required traits of the future yeast cell factories will be assembled into genetic modules for fast transfer between strains. These developments will benefit from progress in bio-computational methods, which allow for the integration of different kinds of data sets and algorithms, and from rapid advancement in genome editing, which will enable multiplexed targeted integration of whole heterologous pathways. The overall goal will be to provide a collection of modules and circuits that work independently and can be combined at will, depending on the individual conditions, and will result in an optimal synthetic host for a given production process.
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Affiliation(s)
- Martin Kavšček
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010, Graz, Austria.
| | - Martin Stražar
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia.
| | - Tomaž Curk
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia.
| | - Klaus Natter
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/II, 8010, Graz, Austria.
| | - Uroš Petrovič
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia.
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Engineering Saccharomyces pastorianus for the co-utilisation of xylose and cellulose from biomass. Microb Cell Fact 2015; 14:61. [PMID: 25928878 PMCID: PMC4417197 DOI: 10.1186/s12934-015-0242-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 04/08/2015] [Indexed: 01/24/2023] Open
Abstract
Background Lignocellulosic biomass is a viable source of renewable energy for bioethanol production. For the efficient conversion of biomass into bioethanol, it is essential that sugars from both the cellulose and hemicellulose fractions of lignocellulose be utilised. Results We describe the development of a recombinant yeast system for the fermentation of cellulose and xylose, the most abundant pentose sugar in the hemicellulose fraction of biomass. The brewer’s yeast Saccharomyces pastorianus was chosen as a host as significantly higher recombinant enzyme activities are achieved, when compared to the more commonly used S. cerevisiae. When expressed in S. pastorianus, the Trichoderma reesei xylose oxidoreductase pathway was more efficient at alcohol production from xylose than the xylose isomerase pathway. The alcohol yield was influenced by the concentration of xylose in the medium and was significantly improved by the additional expression of a gene encoding for xylulose kinase. The xylose reductase, xylitol dehydrogenase and xylulose kinase genes were co-expressed with genes encoding for the three classes of T. reesei cellulases, namely endoglucanase (EG2), cellobiohydrolysase (CBH2) and β-glucosidase (BGL1). The initial metabolism of xylose by the engineered strains facilitated production of cellulases at fermentation temperatures. The sequential metabolism of xylose and cellulose generated an alcohol yield of 82% from the available sugars. Several different types of biomass, such as the energy crop Miscanthus sinensis and the industrial waste, brewer’s spent grains, were examined as biomass sources for fermentation using the developed yeast strains. Xylose metabolism and cell growth were inhibited in fermentations carried out with acid-treated spent grain liquor, resulting in a 30% reduction in alcohol yield compared to fermentations carried out with mixed sugar substrates. Conclusions Reconstitution of complete enzymatic pathways for cellulose hydrolysis and xylose utilisation in S. pastorianus facilitates the co-fermentation of cellulose and xylose without the need for added exogenous cellulases and provides a basis for the development of a consolidated process for co-utilisation of hemicellulose and cellulose sugars. Electronic supplementary material The online version of this article (doi:10.1186/s12934-015-0242-4) contains supplementary material, which is available to authorized users.
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Jarmander J, Belotserkovsky J, Sjöberg G, Guevara-Martínez M, Pérez-Zabaleta M, Quillaguamán J, Larsson G. Cultivation strategies for production of (R)-3-hydroxybutyric acid from simultaneous consumption of glucose, xylose and arabinose by Escherichia coli. Microb Cell Fact 2015; 14:51. [PMID: 25889969 PMCID: PMC4405896 DOI: 10.1186/s12934-015-0236-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/30/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lignocellulosic waste is a desirable biomass for use in second generation biorefineries. Up to 40% of its sugar content consist of pentoses, which organisms either take up sequentially after glucose depletion, or not at all. A previously described Escherichia coli strain, PPA652ara, capable of simultaneous consumption of glucose, xylose and arabinose was in the present work utilized for production of (R)-3-hydroxybutyric acid (3HB) from a mixture of glucose, xylose and arabinose. RESULTS The Halomonas boliviensis genes for 3HB production were for the first time cloned into E. coli PPA652ara, leading to product secretion directly into the medium. Process design was based on comparisons of batch, fed-batch and continuous cultivation, where both excess and limitation of the carbon mixture was studied. Carbon limitation resulted in low specific productivity of 3HB (<2 mg g(-1) h(-1)) compared to carbon excess (25 mg g(-1) h(-1)), but the yield of 3HB/cell dry weight (Y3HB/CDW) was very low (0.06 g g(-1)) during excess. Nitrogen-exhausted conditions could be used to sustain a high specific productivity (31 mg g(-1) h(-1)) and to increase the yield of 3HB/cell dry weight to 1.38 g g(-1). Nitrogen-limited fed-batch process design led to further increased specific productivity (38 mg g(-1) h(-1)) but also to additional cell growth (Y3HB/CDW=0.16 g g(-1)). Strain PPA652ara did under all processing conditions simultaneously consume glucose, xylose and arabinose, which was not the case for a reference wild type E. coli, which also gave a higher carbon flux to acetic acid. CONCLUSIONS It was demonstrated that by using E. coli PPA652ara, it was possible to design a production process for 3HB from a mixture of glucose, xylose and arabinose where all sugars were consumed. An industrial 3HB production process is proposed to be divided into a growth and a production phase, and nitrogen depletion/limitation is a potential strategy to maximize the yield of 3HB/CDW in the latter. The specific productivity of 3HB reported here from glucose, xylose and arabinose by E. coli is further comparable to the current state of the art for production from glucose sources.
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Affiliation(s)
- Johan Jarmander
- School of Biotechnology, Division of Industrial Biotechnology, KTH Royal Institute of Technology, SE 106 91, Stockholm, Sweden.
| | - Jaroslav Belotserkovsky
- School of Biotechnology, Division of Industrial Biotechnology, KTH Royal Institute of Technology, SE 106 91, Stockholm, Sweden.
| | - Gustav Sjöberg
- School of Biotechnology, Division of Industrial Biotechnology, KTH Royal Institute of Technology, SE 106 91, Stockholm, Sweden.
| | - Mónica Guevara-Martínez
- School of Biotechnology, Division of Industrial Biotechnology, KTH Royal Institute of Technology, SE 106 91, Stockholm, Sweden.
- Center of Biotechnology, Faculty of Science and Technology, Universidad Mayor de San Simón, Cochabamba, Bolivia.
| | - Mariel Pérez-Zabaleta
- School of Biotechnology, Division of Industrial Biotechnology, KTH Royal Institute of Technology, SE 106 91, Stockholm, Sweden.
- Center of Biotechnology, Faculty of Science and Technology, Universidad Mayor de San Simón, Cochabamba, Bolivia.
| | - Jorge Quillaguamán
- Center of Biotechnology, Faculty of Science and Technology, Universidad Mayor de San Simón, Cochabamba, Bolivia.
| | - Gen Larsson
- School of Biotechnology, Division of Industrial Biotechnology, KTH Royal Institute of Technology, SE 106 91, Stockholm, Sweden.
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Challenges for the production of bioethanol from biomass using recombinant yeasts. ADVANCES IN APPLIED MICROBIOLOGY 2015; 92:89-125. [PMID: 26003934 DOI: 10.1016/bs.aambs.2015.02.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Lignocellulose biomass, one of the most abundant renewable resources on the planet, is an alternative sustainable energy source for the production of second-generation biofuels. Energy in the form of simple or complex carbohydrates can be extracted from lignocellulose biomass and fermented by microorganisms to produce bioethanol. Despite 40 years of active and cutting-edge research invested into the development of technologies to produce bioethanol from lignocellulosic biomass, the process remains commercially unviable. This review describes the achievements that have been made in generating microorganisms capable of utilizing both simple and complex sugars from lignocellulose biomass and the fermentation of these sugars into ethanol. We also provide a discussion on the current "roadblocks" standing in the way of making second-generation bioethanol a commercially viable alternative to fossil fuels.
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Trama B, Fernandes JDS, Labuto G, Oliveira JCFD, Viana-Niero C, Pascon RC, Vallim MA. The Evaluation of Bioremediation Potential of a Yeast Collection Isolated from Composting. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/aim.2014.412088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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41
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Lambertz C, Garvey M, Klinger J, Heesel D, Klose H, Fischer R, Commandeur U. Challenges and advances in the heterologous expression of cellulolytic enzymes: a review. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:135. [PMID: 25356086 PMCID: PMC4212100 DOI: 10.1186/s13068-014-0135-5] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/03/2014] [Indexed: 05/03/2023]
Abstract
Second generation biofuel development is increasingly reliant on the recombinant expression of cellulases. Designing or identifying successful expression systems is thus of preeminent importance to industrial progress in the field. Recombinant production of cellulases has been performed using a wide range of expression systems in bacteria, yeasts and plants. In a number of these systems, particularly when using bacteria and plants, significant challenges have been experienced in expressing full-length proteins or proteins at high yield. Further difficulties have been encountered in designing recombinant systems for surface-display of cellulases and for use in consolidated bioprocessing in bacteria and yeast. For establishing cellulase expression in plants, various strategies are utilized to overcome problems, such as the auto-hydrolysis of developing plant cell walls. In this review, we investigate the major challenges, as well as the major advances made to date in the recombinant expression of cellulases across the commonly used bacterial, plant and yeast systems. We review some of the critical aspects to be considered for industrial-scale cellulase production.
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Affiliation(s)
- Camilla Lambertz
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Megan Garvey
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- />Present address: School of Medicine, Deakin University, CSIRO Australian Animal Health Laboratory, 5 Portarlington Rd, Newcomb, VIC 3219 Australia
| | - Johannes Klinger
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Dirk Heesel
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Holger Klose
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- />Present address: Institute for Botany and Molecular Genetics, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Rainer Fischer
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- />Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstrasse 6, 52074 Aachen, Germany
| | - Ulrich Commandeur
- />Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
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