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Azarakhsh FAS, Ziloue H, Ebrahimian F, Khoshnevisan B, Denayer JFM, Karimi K. Life cycle analysis of apple pomace biorefining for biofuel and pectin production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 951:175780. [PMID: 39187078 DOI: 10.1016/j.scitotenv.2024.175780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 08/07/2024] [Accepted: 08/23/2024] [Indexed: 08/28/2024]
Abstract
This study investigated the environmental impacts associated with converting apple pomace, a globally abundant resource, into biofuels and high-value products using a comparative consequential life cycle assessment. In three developed scenarios, an acid pretreatment method was applied and the pretreated liquid was used for ethanol and pectin production. The pretreated solids were utilized to produce different products: scenario 1 produced biogas, scenario 2 generated butanol, and scenario 3 yielded both biogas and butanol from the solids. The results demonstrated that scenario 1 exhibited the best performance compared to the other two scenarios, imposing the lowest environmental burdens across all damage categories, including human health, ecosystems, and resources. Despite the induced impacts, the benefits of avoided products, i.e., ethanol, natural gas, butanol, acetone, and pectin, compensated for these induced environmental impacts to some extent. The results also revealed that among all products generated through the biorefineries, first-generation ethanol substitution had the most significant positive environmental impacts. Overall, the biorefinery developed in scenario 1 represents the most feasible strategy for a circular bioeconomy. It performs 84.38 % and 72.98 % better than scenarios 2 and 3 in terms of human health, 85.34 % and 74.54 % better in terms of ecosystems, and more than 100 % better in terms of resources. Conversely, scenario 2 resulted in the highest net impacts across all damage categories. Furthermore, in scenario 1, the midpoint results showed 83.10 % and 71.08 % lower impacts on global warming, 85.15 % and 74.17 % lower impacts on terrestrial acidification, and 99.26 % and 98.53 % lower impacts on fossil resource scarcity compared to scenarios 2 and 3, respectively. In conclusion, the first scenario shows promise for the sustainable valorization of apple pomace.
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Affiliation(s)
| | - Hamid Ziloue
- Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran
| | - Farinaz Ebrahimian
- Future Energy Center, School of Business, Society and Engineering, Mälardalen University, Västerås, Sweden
| | | | - Joeri F M Denayer
- Department of Chemical Engineering, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Keikhosro Karimi
- Department of Chemical Engineering, Vrije Universiteit Brussel, 1050 Brussels, Belgium.
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2
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Tsegaye KN, Alemnew M, Berhane N. Saccharomyces cerevisiae for lignocellulosic ethanol production: a look at key attributes and genome shuffling. Front Bioeng Biotechnol 2024; 12:1466644. [PMID: 39386039 PMCID: PMC11461319 DOI: 10.3389/fbioe.2024.1466644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Accepted: 09/17/2024] [Indexed: 10/12/2024] Open
Abstract
These days, bioethanol research is looking at using non-edible plant materials, called lignocellulosic feedstocks, because they are cheap, plentiful, and renewable. However, these materials are complex and require pretreatment to release fermentable sugars. Saccharomyces cerevisiae, the industrial workhorse for bioethanol production, thrives in sugary environments and can handle high levels of ethanol. However, during lignocellulose fermentation, S. cerevisiae faces challenges like high sugar and ethanol concentrations, elevated temperatures, and even some toxic substances present in the pretreated feedstocks. Also, S. cerevisiae struggles to efficiently convert all the sugars (hexose and pentose) present in lignocellulosic hydrolysates. That's why scientists are exploring the natural variations within Saccharomyces strains and even figuring out ways to improve them. This review highlights why Saccharomyces cerevisiae remains a crucial player for large-scale bioethanol production from lignocellulose and discusses the potential of genome shuffling to create even more efficient yeast strains.
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Affiliation(s)
- Kindu Nibret Tsegaye
- Department of Biology, Gondar College of Teachers Education, Gondar, Ethiopia
- Institute of Biotechnology, University of Gondar, Gondar, Ethiopia
| | - Marew Alemnew
- Institute of Biotechnology, University of Gondar, Gondar, Ethiopia
| | - Nega Berhane
- Institute of Biotechnology, University of Gondar, Gondar, Ethiopia
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3
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Antonopoulou G, Kamilari M, Georgopoulou D, Ntaikou I. Using Extracted Sugars from Spoiled Date Fruits as a Sustainable Feedstock for Ethanol Production by New Yeast Isolates. Molecules 2024; 29:3816. [PMID: 39202895 PMCID: PMC11357582 DOI: 10.3390/molecules29163816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2024] [Revised: 07/27/2024] [Accepted: 08/06/2024] [Indexed: 09/03/2024] Open
Abstract
This study focuses on investigating sugar recovery from spoiled date fruits (SDF) for sustainable ethanol production using newly isolated yeasts. Upon their isolation from different food products, yeast strains were identified through PCR amplification of the D1/D2 region and subsequent comparison with the GenBank database, confirming isolates KKU30, KKU32, and KKU33 as Saccharomyces cerevisiae; KKU21 as Zygosaccharomyces rouxii; and KKU35m as Meyerozyma guilliermondii. Optimization of sugar extraction from SDF pulp employed response surface methodology (RSM), varying solid loading (20-40%), temperature (20-40 °C), and extraction time (10-30 min). Linear models for sugar concentration (R1) and extraction efficiency (R2) showed relatively high R2 values, indicating a good model fit. Statistical analysis revealed significant effects of temperature and extraction time on extraction efficiency. The results of batch ethanol production from SDF extracts using mono-cultures indicated varying consumption rates of sugars, biomass production, and ethanol yields among strains. Notably, S. cerevisiae strains exhibited rapid sugar consumption and high ethanol productivity, outperforming Z. rouxii and M. guilliermondii, and they were selected for scaling up the process at fed-batch mode in a co-culture. Co-cultivation resulted in complete sugar consumption and higher ethanol yields compared to mono-cultures, whereas the ethanol titer reached 46.8 ± 0.2 g/L.
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Affiliation(s)
- Georgia Antonopoulou
- Department of Sustainable Agriculture, University of Patras, 2 Georgiou Seferi St., GR-30100 Agrinio, Greece;
- Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou, GR-26504 Patra, Greece
| | - Maria Kamilari
- Department of Plant Protection Patras, Institute of Industrial and Forage Crops, Hellenic Agricultural Organization ‘DIMITRA’, GR-26442 Patras, Greece
- Health Faculty, Metropolitan College, Campus of Patras, 50 Ermou St., GR-26221 Patra, Greece;
| | - Dimitra Georgopoulou
- Department of Chemical Engineering, University of Patras, GR-26500 Patra, Greece;
| | - Ioanna Ntaikou
- Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou, GR-26504 Patra, Greece
- Department of Civil Engineering, University of Patras, GR-26500 Patra, Greece
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4
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Jawad M, Wang H, Wu Y, Rehman O, Song Y, Xu R, Zhang Q, Gao H, Xue C. Lignocellulosic ethanol and butanol production by Saccharomyces cerevisiae and Clostridium beijerinckii co-culture using non-detoxified corn stover hydrolysate. J Biotechnol 2024; 379:1-5. [PMID: 37944902 DOI: 10.1016/j.jbiotec.2023.11.002] [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: 10/19/2023] [Accepted: 11/06/2023] [Indexed: 11/12/2023]
Abstract
Considering global economic and environmental -benefits, green renewable biofuels such as ethanol and butanol are considered as sustainable alternatives to fossil fuels. Thus, developing a co-culture strategy for ethanol and butanol production by Saccharomyces cerevisiae and Clostridium beijerinckii has emerged as a promising approach for biofuel production from lignocellulosic biomass. This study developed a co-culture of S. cerevisiae and C. beijerinckii for ethanol and butanol production from non-detoxified corn stover hydrolysate. By firstly inoculating 3 % S. cerevisiae and then 7 % C. beijerinckii with 8-10 h time intervals, the optimized co-culture process gave 24.0 g/L ABE (20.8 g/L ethanol and 2.4 g/L butanol), obtaining ABE yield and productivity of 0.421 g/g and 0.55 g/L/h. The demonstrated co-culture strategy made full use of hexose and pentose in hydrolysate and contributed to total yield and efficiency compared to conventional ethanol or ABE fermentation, indicating its great potential for developing economically feasible and sustainable bioalcohols production.
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Affiliation(s)
- Muhammad Jawad
- MOE Key Laboratory of Bio-Intelligent Manufacturing, Engineering Research Center of Application and Transformation for Synthetic Biology, School of Bioengineering, Dalian University of Technology, Dalian 116024, Liaoning, China
| | - Huan Wang
- MOE Key Laboratory of Bio-Intelligent Manufacturing, Engineering Research Center of Application and Transformation for Synthetic Biology, School of Bioengineering, Dalian University of Technology, Dalian 116024, Liaoning, China
| | - Youduo Wu
- MOE Key Laboratory of Bio-Intelligent Manufacturing, Engineering Research Center of Application and Transformation for Synthetic Biology, School of Bioengineering, Dalian University of Technology, Dalian 116024, Liaoning, China; Ningbo Institute of Dalian University of Technology, Ningbo 315016, China.
| | - Omama Rehman
- MOE Key Laboratory of Bio-Intelligent Manufacturing, Engineering Research Center of Application and Transformation for Synthetic Biology, School of Bioengineering, Dalian University of Technology, Dalian 116024, Liaoning, China
| | - Yongxiu Song
- Ningbo Institute of Dalian University of Technology, Ningbo 315016, China
| | - Rui Xu
- Yunnan Provincial Rural Energy Engineering Key Laboratory, Kunming 650600, China
| | - Quan Zhang
- SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co., Ltd., Dalian 116041, China
| | - Huipeng Gao
- SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co., Ltd., Dalian 116041, China
| | - Chuang Xue
- MOE Key Laboratory of Bio-Intelligent Manufacturing, Engineering Research Center of Application and Transformation for Synthetic Biology, School of Bioengineering, Dalian University of Technology, Dalian 116024, Liaoning, China; Ningbo Institute of Dalian University of Technology, Ningbo 315016, China.
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5
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Gao J, Yu W, Li Y, Jin M, Yao L, Zhou YJ. Engineering co-utilization of glucose and xylose for chemical overproduction from lignocellulose. Nat Chem Biol 2023; 19:1524-1531. [PMID: 37620399 DOI: 10.1038/s41589-023-01402-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 07/10/2023] [Indexed: 08/26/2023]
Abstract
Bio-refining lignocellulose could provide a sustainable supply of fuels and fine chemicals; however, the challenges associated with the co-utilization of xylose and glucose typically compromise the efficiency of lignocellulose conversion. Here we engineered the industrial yeast Ogataea polymorpha (Hansenula polymorpha) for lignocellulose biorefinery by facilitating the co-utilization of glucose and xylose to optimize the production of free fatty acids (FFAs) and 3-hydroxypropionic acid (3-HP) from lignocellulose. We rewired the central metabolism for the enhanced supply of acetyl-coenzyme A and nicotinamide adenine dinucleotide phosphate hydrogen, obtaining 30.0 g l-1 of FFAs from glucose, with productivity of up to 0.27 g l-1 h-1. Strengthening xylose uptake and catabolism promoted the synchronous utilization of glucose and xylose, which enabled the production of 38.2 g l-1 and 7.0 g l-1 FFAs from the glucose-xylose mixture and lignocellulosic hydrolysates, respectively. Finally, this efficient cell factory was metabolically transformed for 3-HP production with the highest titer of 79.6 g l-1 in fed-batch fermentation in mixed glucose and xylose.
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Affiliation(s)
- Jiaoqi Gao
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
| | - Wei Yu
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- University of Chinese Academy of Sciences, Beijing, PR China
| | - Yunxia Li
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, PR China
| | - Lun Yao
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China
| | - Yongjin J Zhou
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China.
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China.
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, PR China.
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6
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Saxena A, Hussain A, Parveen F, Ashfaque M. Current status of metabolic engineering of microorganisms for bioethanol production by effective utilization of pentose sugars of lignocellulosic biomass. Microbiol Res 2023; 276:127478. [PMID: 37625339 DOI: 10.1016/j.micres.2023.127478] [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: 05/08/2023] [Revised: 08/01/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023]
Abstract
Lignocellulosic biomass, consisting of homo- and heteropolymeric sugars, acts as a substrate for the generation of valuable biochemicals and biomaterials. The readily available hexoses are easily utilized by microbes due to the presence of transporters and native metabolic pathways. But, utilization of pentose sugar viz., xylose and arabinose are still challenging due to several reasons including (i) the absence of the particular native pathways and transporters, (ii) the presence of inhibitors, and (iii) lower uptake of pentose sugars. These challenges can be overcome by manipulating metabolic pathways/glycosidic enzymes cascade by using genetic engineering tools involving inverse-metabolic engineering, ex-vivo isomerization, Adaptive Laboratory Evolution, Directed Metabolic Engineering, etc. Metabolic engineering of bacteria and fungi for the utilization of pentose sugars for bioethanol production is the focus area of research in the current decade. This review outlines current approaches to biofuel development and strategies involved in the metabolic engineering of different microbes that can uptake pentose for bioethanol production.
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Affiliation(s)
- Ayush Saxena
- Lignocellulose & Biofuel Laboratory, Department of Biosciences, Integral University, Lucknow 226026, Uttar Pradesh, India.
| | - Akhtar Hussain
- Lignocellulose & Biofuel Laboratory, Department of Biosciences, Integral University, Lucknow 226026, Uttar Pradesh, India.
| | - Fouziya Parveen
- Lignocellulose & Biofuel Laboratory, Department of Biosciences, Integral University, Lucknow 226026, Uttar Pradesh, India.
| | - Mohammad Ashfaque
- Lignocellulose & Biofuel Laboratory, Department of Biosciences, Integral University, Lucknow 226026, Uttar Pradesh, India.
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7
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Khamwachirapithak P, Sae-Tang K, Mhuantong W, Tanapongpipat S, Zhao XQ, Liu CG, Wei DQ, Champreda V, Runguphan W. Optimizing Ethanol Production in Saccharomyces cerevisiae at Ambient and Elevated Temperatures through Machine Learning-Guided Combinatorial Promoter Modifications. ACS Synth Biol 2023; 12:2897-2908. [PMID: 37681736 PMCID: PMC10594650 DOI: 10.1021/acssynbio.3c00199] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Indexed: 09/09/2023]
Abstract
Bioethanol has gained popularity in recent decades as an ecofriendly alternative to fossil fuels due to increasing concerns about global climate change. However, economically viable ethanol fermentation remains a challenge. High-temperature fermentation can reduce production costs, but Saccharomyces cerevisiae yeast strains normally ferment poorly under high temperatures. In this study, we present a machine learning (ML) approach to optimize bioethanol production in S. cerevisiae by fine-tuning the promoter activities of three endogenous genes. We created 216 combinatorial strains of S. cerevisiae by replacing native promoters with five promoters of varying strengths to regulate ethanol production. Promoter replacement resulted in a 63% improvement in ethanol production at 30 °C. We created an ML-guided workflow by utilizing XGBoost to train high-performance models based on promoter strengths and cellular metabolite concentrations obtained from ethanol production of 216 combinatorial strains at 30 °C. This strategy was then applied to optimize ethanol production at 40 °C, where we selected 31 strains for experimental fermentation. This reduced experimental load led to a 7.4% increase in ethanol production in the second round of the ML-guided workflow. Our study offers a comprehensive library of promoter strength modifications for key ethanol production enzymes, showcasing how machine learning can guide yeast strain optimization and make bioethanol production more cost-effective and efficient. Furthermore, we demonstrate that metabolic engineering processes can be accelerated and optimized through this approach.
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Affiliation(s)
- Peerapat Khamwachirapithak
- National
Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency
(NSTDA) 111 Thailand Science Park, Phahonyothin Road, Khlong
Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Kittapong Sae-Tang
- National
Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency
(NSTDA) 111 Thailand Science Park, Phahonyothin Road, Khlong
Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Wuttichai Mhuantong
- National
Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency
(NSTDA) 111 Thailand Science Park, Phahonyothin Road, Khlong
Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Sutipa Tanapongpipat
- National
Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency
(NSTDA) 111 Thailand Science Park, Phahonyothin Road, Khlong
Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Xin-Qing Zhao
- State
Key Laboratory of Microbial Metabolism, Joint International Research
Laboratory of Metabolic & Developmental Sciences, School of Life
Sciences and Biotechnology, Shanghai Jiao
Tong University, Shanghai 200240, People’s
Republic of China
| | - Chen-Guang Liu
- State
Key Laboratory of Microbial Metabolism, Joint International Research
Laboratory of Metabolic & Developmental Sciences, School of Life
Sciences and Biotechnology, Shanghai Jiao
Tong University, Shanghai 200240, People’s
Republic of China
| | - Dong-Qing Wei
- Department
of Bioinformatics and Biological Statistics, School of Life Sciences
and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Verawat Champreda
- National
Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency
(NSTDA) 111 Thailand Science Park, Phahonyothin Road, Khlong
Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Weerawat Runguphan
- National
Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency
(NSTDA) 111 Thailand Science Park, Phahonyothin Road, Khlong
Nueng, Khlong Luang, Pathum Thani 12120, Thailand
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Yatabe F, Seike T, Okahashi N, Ishii J, Matsuda F. Improvement of ethanol and 2,3-butanediol production in Saccharomyces cerevisiae by ATP wasting. Microb Cell Fact 2023; 22:204. [PMID: 37807050 PMCID: PMC10560415 DOI: 10.1186/s12934-023-02221-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/30/2023] [Indexed: 10/10/2023] Open
Abstract
BACKGROUND "ATP wasting" has been observed in 13C metabolic flux analyses of Saccharomyces cerevisiae, a yeast strain commonly used to produce ethanol. Some strains of S. cerevisiae, such as the sake strain Kyokai 7, consume approximately two-fold as much ATP as laboratory strains. Increased ATP consumption may be linked to the production of ethanol, which helps regenerate ATP. RESULTS This study was conducted to enhance ethanol and 2,3-butanediol (2,3-BDO) production in the S. cerevisiae strains, ethanol-producing strain BY318 and 2,3-BDO-producing strain YHI030, by expressing the fructose-1,6-bisphosphatase (FBPase) and ATP synthase (ATPase) genes to induce ATP dissipation. The introduction of a futile cycle for ATP consumption in the pathway was achieved by expressing various FBPase and ATPase genes from Escherichia coli and S. cerevisiae in the yeast strains. The production of ethanol and 2,3-BDO was evaluated using high-performance liquid chromatography and gas chromatography, and fermentation tests were performed on synthetic media under aerobic conditions in batch culture. The results showed that in the BY318-opt_ecoFBPase (expressing opt_ecoFBPase) and BY318-ATPase (expressing ATPase) strains, specific glucose consumption was increased by 30% and 42%, respectively, and the ethanol production rate was increased by 24% and 45%, respectively. In contrast, the YHI030-opt_ecoFBPase (expressing opt_ecoFBPase) and YHI030-ATPase (expressing ATPase) strains showed increased 2,3-BDO yields of 26% and 18%, respectively, and the specific production rate of 2,3-BDO was increased by 36%. Metabolomic analysis confirmed the introduction of the futile cycle. CONCLUSION ATP wasting may be an effective strategy for improving the fermentative biosynthetic capacity of S. cerevisiae, and increased ATP consumption may be a useful tool in some alcohol-producing strains.
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Affiliation(s)
- Futa Yatabe
- Department of Bioinformatics Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Taisuke Seike
- Department of Bioinformatics Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Industrial Biotechnology Initiative Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Nobuyuki Okahashi
- Department of Bioinformatics Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Industrial Biotechnology Initiative Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Analytical Innovation Research Laboratory, Graduate School of Engineering, Osaka University Shimadzu, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Jun Ishii
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo, 657-8501, Japan
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo, 657-8501, Japan
| | - Fumio Matsuda
- Department of Bioinformatics Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Industrial Biotechnology Initiative Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Analytical Innovation Research Laboratory, Graduate School of Engineering, Osaka University Shimadzu, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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9
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Topaloğlu A, Esen Ö, Turanlı-Yıldız B, Arslan M, Çakar ZP. From Saccharomyces cerevisiae to Ethanol: Unlocking the Power of Evolutionary Engineering in Metabolic Engineering Applications. J Fungi (Basel) 2023; 9:984. [PMID: 37888240 PMCID: PMC10607480 DOI: 10.3390/jof9100984] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/25/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023] Open
Abstract
Increased human population and the rapid decline of fossil fuels resulted in a global tendency to look for alternative fuel sources. Environmental concerns about fossil fuel combustion led to a sharp move towards renewable and environmentally friendly biofuels. Ethanol has been the primary fossil fuel alternative due to its low carbon emission rates, high octane content and comparatively facile microbial production processes. In parallel to the increased use of bioethanol in various fields such as transportation, heating and power generation, improvements in ethanol production processes turned out to be a global hot topic. Ethanol is by far the leading yeast output amongst a broad spectrum of bio-based industries. Thus, as a well-known platform microorganism and native ethanol producer, baker's yeast Saccharomyces cerevisiae has been the primary subject of interest for both academic and industrial perspectives in terms of enhanced ethanol production processes. Metabolic engineering strategies have been primarily adopted for direct manipulation of genes of interest responsible in mainstreams of ethanol metabolism. To overcome limitations of rational metabolic engineering, an alternative bottom-up strategy called inverse metabolic engineering has been widely used. In this context, evolutionary engineering, also known as adaptive laboratory evolution (ALE), which is based on random mutagenesis and systematic selection, is a powerful strategy to improve bioethanol production of S. cerevisiae. In this review, we focus on key examples of metabolic and evolutionary engineering for improved first- and second-generation S. cerevisiae bioethanol production processes. We delve into the current state of the field and show that metabolic and evolutionary engineering strategies are intertwined and many metabolically engineered strains for bioethanol production can be further improved by powerful evolutionary engineering strategies. We also discuss potential future directions that involve recent advancements in directed genome evolution, including CRISPR-Cas9 technology.
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Affiliation(s)
- Alican Topaloğlu
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul 34469, Türkiye; (A.T.); (Ö.E.)
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul 34469, Türkiye;
| | - Ömer Esen
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul 34469, Türkiye; (A.T.); (Ö.E.)
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul 34469, Türkiye;
| | - Burcu Turanlı-Yıldız
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul 34469, Türkiye;
| | - Mevlüt Arslan
- Department of Genetics, Faculty of Veterinary Medicine, Van Yüzüncü Yıl University, Van 65000, Türkiye;
| | - Zeynep Petek Çakar
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul 34469, Türkiye; (A.T.); (Ö.E.)
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul 34469, Türkiye;
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10
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Gutiérrez-Corona JF, González-Hernández GA, Padilla-Guerrero IE, Olmedo-Monfil V, Martínez-Rocha AL, Patiño-Medina JA, Meza-Carmen V, Torres-Guzmán JC. Fungal Alcohol Dehydrogenases: Physiological Function, Molecular Properties, Regulation of Their Production, and Biotechnological Potential. Cells 2023; 12:2239. [PMID: 37759461 PMCID: PMC10526403 DOI: 10.3390/cells12182239] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/27/2023] [Accepted: 08/31/2023] [Indexed: 09/29/2023] Open
Abstract
Fungal alcohol dehydrogenases (ADHs) participate in growth under aerobic or anaerobic conditions, morphogenetic processes, and pathogenesis of diverse fungal genera. These processes are associated with metabolic operation routes related to alcohol, aldehyde, and acid production. The number of ADH enzymes, their metabolic roles, and their functions vary within fungal species. The most studied ADHs are associated with ethanol metabolism, either as fermentative enzymes involved in the production of this alcohol or as oxidative enzymes necessary for the use of ethanol as a carbon source; other enzymes participate in survival under microaerobic conditions. The fast generation of data using genome sequencing provides an excellent opportunity to determine a correlation between the number of ADHs and fungal lifestyle. Therefore, this review aims to summarize the latest knowledge about the importance of ADH enzymes in the physiology and metabolism of fungal cells, as well as their structure, regulation, evolutionary relationships, and biotechnological potential.
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Affiliation(s)
- J. Félix Gutiérrez-Corona
- Departamento de Biología, DCNE, Universidad de Guanajuato, Guanajuato C.P. 36050, Mexico; (G.A.G.-H.); (I.E.P.-G.); (V.O.-M.); (A.L.M.-R.)
| | - Gloria Angélica González-Hernández
- Departamento de Biología, DCNE, Universidad de Guanajuato, Guanajuato C.P. 36050, Mexico; (G.A.G.-H.); (I.E.P.-G.); (V.O.-M.); (A.L.M.-R.)
| | - Israel Enrique Padilla-Guerrero
- Departamento de Biología, DCNE, Universidad de Guanajuato, Guanajuato C.P. 36050, Mexico; (G.A.G.-H.); (I.E.P.-G.); (V.O.-M.); (A.L.M.-R.)
| | - Vianey Olmedo-Monfil
- Departamento de Biología, DCNE, Universidad de Guanajuato, Guanajuato C.P. 36050, Mexico; (G.A.G.-H.); (I.E.P.-G.); (V.O.-M.); (A.L.M.-R.)
| | - Ana Lilia Martínez-Rocha
- Departamento de Biología, DCNE, Universidad de Guanajuato, Guanajuato C.P. 36050, Mexico; (G.A.G.-H.); (I.E.P.-G.); (V.O.-M.); (A.L.M.-R.)
| | - J. Alberto Patiño-Medina
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo (UMSNH), Morelia C.P. 58030, Mexico; (J.A.P.-M.); (V.M.-C.)
| | - Víctor Meza-Carmen
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo (UMSNH), Morelia C.P. 58030, Mexico; (J.A.P.-M.); (V.M.-C.)
| | - Juan Carlos Torres-Guzmán
- Departamento de Biología, DCNE, Universidad de Guanajuato, Guanajuato C.P. 36050, Mexico; (G.A.G.-H.); (I.E.P.-G.); (V.O.-M.); (A.L.M.-R.)
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11
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Peña-Castro JM, Muñoz-Páez KM, Robledo-Narvaez PN, Vázquez-Núñez E. Engineering the Metabolic Landscape of Microorganisms for Lignocellulosic Conversion. Microorganisms 2023; 11:2197. [PMID: 37764041 PMCID: PMC10535843 DOI: 10.3390/microorganisms11092197] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/16/2023] [Accepted: 08/18/2023] [Indexed: 09/29/2023] Open
Abstract
Bacteria and yeast are being intensively used to produce biofuels and high-added-value products by using plant biomass derivatives as substrates. The number of microorganisms available for industrial processes is increasing thanks to biotechnological improvements to enhance their productivity and yield through microbial metabolic engineering and laboratory evolution. This is allowing the traditional industrial processes for biofuel production, which included multiple steps, to be improved through the consolidation of single-step processes, reducing the time of the global process, and increasing the yield and operational conditions in terms of the desired products. Engineered microorganisms are now capable of using feedstocks that they were unable to process before their modification, opening broader possibilities for establishing new markets in places where biomass is available. This review discusses metabolic engineering approaches that have been used to improve the microbial processing of biomass to convert the plant feedstock into fuels. Metabolically engineered microorganisms (MEMs) such as bacteria, yeasts, and microalgae are described, highlighting their performance and the biotechnological tools that were used to modify them. Finally, some examples of patents related to the MEMs are mentioned in order to contextualize their current industrial use.
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Affiliation(s)
- Julián Mario Peña-Castro
- Centro de Investigaciones Científicas, Instituto de Biotecnología, Universidad del Papaloapan, Tuxtepec 68301, Oaxaca, Mexico;
| | - Karla M. Muñoz-Páez
- CONAHCYT—Instituto de Ingeniería, Unidad Académica Juriquilla, Universidad Nacional Autónoma de México, Queretaro 76230, Queretaro, Mexico;
| | | | - Edgar Vázquez-Núñez
- Grupo de Investigación Sobre Aplicaciones Nano y Bio Tecnológicas para la Sostenibilidad (NanoBioTS), Departamento de Ingenierías Química, Electrónica y Biomédica, División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, Lomas del Campestre, León 37150, Guanajuato, Mexico
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12
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Palliprath S, Poolakkalody NJ, Ramesh K, Mangalan SM, Kabekkodu SP, Santiago R, Manisseri C. Pretreatment of sugarcane postharvest leaves by γ-valerolactone/water/FeCl3 system for enhanced glucan and bioethanol production. INDUSTRIAL CROPS AND PRODUCTS 2023; 197:116571. [DOI: 10.1016/j.indcrop.2023.116571] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
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13
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Østby H, Várnai A. Hemicellulolytic enzymes in lignocellulose processing. Essays Biochem 2023; 67:533-550. [PMID: 37068264 PMCID: PMC10160854 DOI: 10.1042/ebc20220154] [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: 12/15/2022] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 04/19/2023]
Abstract
Lignocellulosic biomass is the most abundant source of carbon-based material on a global basis, serving as a raw material for cellulosic fibers, hemicellulosic polymers, platform sugars, and lignin resins or monomers. In nature, the various components of lignocellulose (primarily cellulose, hemicellulose, and lignin) are decomposed by saprophytic fungi and bacteria utilizing specialized enzymes. Enzymes are specific catalysts and can, in many cases, be produced on-site at lignocellulose biorefineries. In addition to reducing the use of often less environmentally friendly chemical processes, the application of such enzymes in lignocellulose processing to obtain a range of specialty products can maximize the use of the feedstock and valorize many of the traditionally underutilized components of lignocellulose, while increasing the economic viability of the biorefinery. While cellulose has a rich history of use in the pulp and paper industries, the hemicellulosic fraction of lignocellulose remains relatively underutilized in modern biorefineries, among other reasons due to the heterogeneous chemical structure of hemicellulose polysaccharides, the composition of which varies significantly according to the feedstock and the choice of pretreatment method and extraction solvent. This paper reviews the potential of hemicellulose in lignocellulose processing with focus on what can be achieved using enzymatic means. In particular, we discuss the various enzyme activities required for complete depolymerization of the primary hemicellulose types found in plant cell walls and for the upgrading of hemicellulosic polymers, oligosaccharides, and pentose sugars derived from hemicellulose depolymerization into a broad spectrum of value-added products.
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Affiliation(s)
- Heidi Østby
- Norwegian University of Life Sciences (NMBU), Faculty of Chemistry, Biotechnology and Food Science, P.O. Box 5003, N-1432 Aas, Norway
| | - Anikó Várnai
- Norwegian University of Life Sciences (NMBU), Faculty of Chemistry, Biotechnology and Food Science, P.O. Box 5003, N-1432 Aas, Norway
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14
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Dinh HV, Maranas CD. Evaluating proteome allocation of Saccharomyces cerevisiae phenotypes with resource balance analysis. Metab Eng 2023; 77:242-255. [PMID: 37080482 DOI: 10.1016/j.ymben.2023.04.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/12/2023] [Accepted: 04/16/2023] [Indexed: 04/22/2023]
Abstract
Saccharomyces cerevisiae is an important model organism and a workhorse in bioproduction. Here, we reconstructed a compact and tractable genome-scale resource balance analysis (RBA) model (i.e., named scRBA) to analyze metabolic fluxes and proteome allocation in a computationally efficient manner. Resource capacity models such as scRBA provide the quantitative means to identify bottlenecks in biosynthetic pathways due to enzyme, compartment size, and/or ribosome availability limitations. ATP maintenance rate and in vivo apparent turnover numbers (kapp) were regressed from metabolic flux and protein concentration data to capture observed physiological growth yield and proteome efficiency and allocation, respectively. Estimated parameter values were found to vary with oxygen and nutrient availability. Overall, this work (i) provides condition-specific model parameters to recapitulate phenotypes corresponding to different extracellular environments, (ii) alludes to the enhancing effect of substrate channeling and post-translational activation on in vivo enzyme efficiency in glycolysis and electron transport chain, and (iii) reveals that the Crabtree effect is underpinned by specific limitations in mitochondrial proteome capacity and secondarily ribosome availability rather than overall proteome capacity.
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Affiliation(s)
- Hoang V Dinh
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, USA; Center for Advanced Bioenergy and Bioproducts Innovation, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Costas D Maranas
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, USA; Center for Advanced Bioenergy and Bioproducts Innovation, The Pennsylvania State University, University Park, PA, 16802, USA.
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15
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Kumar S, Agarwal GP, Sreekrishnan TR. Optimization of co-culture condition with respect to aeration and glucose to xylose ratio for bioethanol production. INDIAN CHEMICAL ENGINEER 2023. [DOI: 10.1080/00194506.2023.2190332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Affiliation(s)
- Shashi Kumar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
| | - G. P. Agarwal
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
| | - T. R. Sreekrishnan
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
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16
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Pavão G, Sfalcin I, Bonatto D. Biocontainment Techniques and Applications for Yeast Biotechnology. FERMENTATION-BASEL 2023. [DOI: 10.3390/fermentation9040341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Biocontainment techniques for genetically modified yeasts (GMYs) are pivotal due to the importance of these organisms for biotechnological processes and also due to the design of new yeast strains by using synthetic biology tools and technologies. Due to the large genetic modifications that many yeast strains display, it is highly desirable to avoid the leakage of GMY cells into natural environments and, consequently, the spread of synthetic genes and circuits by horizontal or vertical gene transfer mechanisms within the microorganisms. Moreover, it is also desirable to avoid patented yeast gene technologies spreading outside the production facility. In this review, the different biocontainment technologies currently available for GMYs were evaluated. Interestingly, uniplex-type biocontainment approaches (UTBAs), which rely on nutrient auxotrophies induced by gene mutation or deletion or the expression of the simple kill switches apparatus, are still the major biocontainment approaches in use with GMY. While bacteria such as Escherichia coli account for advanced biocontainment technologies based on synthetic biology and multiplex-type biocontainment approaches (MTBAs), GMYs are distant from this scenario due to many reasons. Thus, a comparison of different UTBAs and MTBAs applied for GMY and genetically engineered microorganisms (GEMs) was made, indicating the major advances of biocontainment techniques for GMYs.
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17
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Dygas D, Kręgiel D, Berłowska J. Sugar Beet Pulp as a Biorefinery Substrate for Designing Feed. Molecules 2023; 28:2064. [PMID: 36903310 PMCID: PMC10004680 DOI: 10.3390/molecules28052064] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/20/2023] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
An example of the implementation of the principles of the circular economy is the use of sugar beet pulp as animal feed. Here, we investigate the possible use of yeast strains to enrich waste biomass in single-cell protein (SCP). The strains were evaluated for yeast growth (pour plate method), protein increment (Kjeldahl method), assimilation of free amino nitrogen (FAN), and reduction of crude fiber content. All the tested strains were able to grow on hydrolyzed sugar beet pulp-based medium. The greatest increases in protein content were observed for Candida utilis LOCK0021 and Saccharomyces cerevisiae Ethanol Red (ΔN = 2.33%) on fresh sugar beet pulp, and for Scheffersomyces stipitis NCYC1541 (ΔN = 3.04%) on dried sugar beet pulp. All the strains assimilated FAN from the culture medium. The largest reductions in the crude fiber content of the biomass were recorded for Saccharomyces cerevisiae Ethanol Red (Δ = 10.89%) on fresh sugar beet pulp and Candida utilis LOCK0021 (Δ = 15.05%) on dried sugar beet pulp. The results show that sugar beet pulp provides an excellent matrix for SCP and feed production.
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Affiliation(s)
- Dawid Dygas
- Department of Environmental Biotechnology, Lodz University of Technology, 171/173 Wólczańska Street, 90-530 Łódź, Poland
| | - Dorota Kręgiel
- Department of Environmental Biotechnology, Lodz University of Technology, 171/173 Wólczańska Street, 90-530 Łódź, Poland
| | - Joanna Berłowska
- Department of Environmental Biotechnology, Lodz University of Technology, 171/173 Wólczańska Street, 90-530 Łódź, Poland
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18
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Sibirny AA. Metabolic engineering of non-conventional yeasts for construction of the advanced producers of biofuels and high-value chemicals. BBA ADVANCES 2022; 3:100071. [PMID: 37082251 PMCID: PMC10074886 DOI: 10.1016/j.bbadva.2022.100071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Non-conventional yeasts, i.e. yeasts different from Saccharomyces cerevisiae, represent heterogenous group of unicellular fungi consisting of near 1500 species. Some of these species have interesting and sometimes unique properties like ability to grow on methanol, n-alkanes, ferment pentose sugars xylose and l-arabinose, grow at high temperatures (50°С and more), overproduce riboflavin (vitamin B2) and others. These unique properties are important for development of basic science; moreover, some of them possess also significant applied interest for elaboration of new biotechnologies. Current paper represents review of the recent own results and of those of other authors in the field of non-conventional yeast study for construction of the advanced producers of biofuels (ethanol, isobutanol) from lignocellulosic sugars glucose and xylose or crude glycerol (Ogataea polymorpha, Magnusiomyces magnusii) and vitamin B2 (riboflavin) from glucose and cheese whey (Candida famata).
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Affiliation(s)
- Andriy A. Sibirny
- Institute of Cell Biology, NAS of Ukraine, Drahomanov Street 14/16, Lviv 79005 Ukraine
- University of Rzeszow, Zelwerowicza 4, Rzeszow 35-601 Poland
- Corresponding author at: Institute of Cell Biology, NAS of Ukraine, Drahomanov Street 14/16, Lviv 79005 Ukraine.
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19
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Microorganisms as New Sources of Energy. ENERGIES 2022. [DOI: 10.3390/en15176365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The use of fossil energy sources has a negative impact on the economic and socio-political stability of specific regions and countries, causing environmental changes due to the emission of greenhouse gases. Moreover, the stocks of mineral energy are limited, causing the demand for new types and forms of energy. Biomass is a renewable energy source and represents an alternative to fossil energy sources. Microorganisms produce energy from the substrate and biomass, i.e., from substances in the microenvironment, to maintain their metabolism and life. However, specialized microorganisms also produce specific metabolites under almost abiotic circumstances that often do not have the immediate task of sustaining their own lives. This paper presents the action of biogenic and biogenic–thermogenic microorganisms, which produce methane, alcohols, lipids, triglycerides, and hydrogen, thus often creating renewable energy from waste biomass. Furthermore, some microorganisms acquire new or improved properties through genetic interventions for producing significant amounts of energy. In this way, they clean the environment and can consume greenhouse gases. Particularly suitable are blue-green algae or cyanobacteria but also some otherwise pathogenic microorganisms (E. coli, Klebsiella, and others), as well as many other specialized microorganisms that show an incredible ability to adapt. Microorganisms can change the current paradigm, energy–environment, and open up countless opportunities for producing new energy sources, especially hydrogen, which is an ideal energy source for all systems (biological, physical, technological). Developing such energy production technologies can significantly change the already achieved critical level of greenhouse gases that significantly affect the climate.
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20
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Semkiv MV, Ruchala J, Tsaruk AY, Zazulya AZ, Vasylyshyn RV, Dmytruk OV, Zuo M, Kang Y, Dmytruk KV, Sibirny AA. The role of hexose transporter-like sensor hxs1 and transcription activator involved in carbohydrate sensing azf1 in xylose and glucose fermentation in the thermotolerant yeast Ogataea polymorpha. Microb Cell Fact 2022; 21:162. [PMID: 35964033 PMCID: PMC9375311 DOI: 10.1186/s12934-022-01889-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/06/2022] [Indexed: 11/24/2022] Open
Abstract
Background Fuel ethanol from lignocellulose could be important source of renewable energy. However, to make the process feasible, more efficient microbial fermentation of pentose sugars, mainly xylose, should be achieved. The native xylose-fermenting thermotolerant yeast Ogataea polymorpha is a promising organism for further development. Efficacy of xylose alcoholic fermentation by O. polymorpha was significantly improved by metabolic engineering. Still, genes involved in regulation of xylose fermentation are insufficiently studied. Results We isolated an insertional mutant of O.polymorpha with impaired ethanol production from xylose. The insertion occurred in the gene HXS1 that encodes hexose transporter-like sensor, a close homolog of Saccharomyces cerevisiae sensors Snf3 and Rgt2. The role of this gene in xylose utilization and fermentation was not previously elucidated. We additionally analyzed O.polymorpha strains with the deletion and overexpression of the corresponding gene. Strains with deletion of the HXS1 gene had slower rate of glucose and xylose consumption and produced 4 times less ethanol than the wild-type strain, whereas overexpression of HXS1 led to 10% increase of ethanol production from glucose and more than 2 times increase of ethanol production from xylose. We also constructed strains of O.polymorpha with overexpression of the gene AZF1 homologous to S. cerevisiae AZF1 gene which encodes transcription activator involved in carbohydrate sensing. Such transformants produced 10% more ethanol in glucose medium and 2.4 times more ethanol in xylose medium. Besides, we deleted the AZF1 gene in O. polymorpha. Ethanol accumulation in xylose and glucose media in such deletion strains dropped 1.5 and 1.8 times respectively. Overexpression of the HXS1 and AZF1 genes was also obtained in the advanced ethanol producer from xylose. The corresponding strains were characterized by 20–40% elevated ethanol accumulation in xylose medium. To understand underlying mechanisms of the observed phenotypes, specific enzymatic activities were evaluated in the isolated recombinant strains. Conclusions This paper shows the important role of hexose sensor Hxs1 and transcription factor Azf1 in xylose and glucose alcoholic fermentation in the native xylose-fermenting yeast O. polymorpha and suggests potential importance of the corresponding genes for construction of the advanced ethanol producers from the major sugars of lignocellulose.
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Affiliation(s)
- Marta V Semkiv
- Institute of Cell Biology, NAS of Ukraine, Drahomanov St, 14/16, 79005, Lviv, Ukraine
| | - Justyna Ruchala
- University of Rzeszow, Zelwerowicza 4, 35-601, Rzeszow, Poland
| | - Aksynia Y Tsaruk
- Institute of Cell Biology, NAS of Ukraine, Drahomanov St, 14/16, 79005, Lviv, Ukraine
| | - Anastasiya Z Zazulya
- Institute of Cell Biology, NAS of Ukraine, Drahomanov St, 14/16, 79005, Lviv, Ukraine
| | | | - Olena V Dmytruk
- Institute of Cell Biology, NAS of Ukraine, Drahomanov St, 14/16, 79005, Lviv, Ukraine.,University of Rzeszow, Zelwerowicza 4, 35-601, Rzeszow, Poland
| | - MingXing Zuo
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guizhou, 550014, Guiyang, China
| | - Yingqian Kang
- Department of Microbiology, School of Basic Medical Sciences, Guizhou Medical University, Guizhou, 550014, Guiyang, China
| | - Kostyantyn V Dmytruk
- Institute of Cell Biology, NAS of Ukraine, Drahomanov St, 14/16, 79005, Lviv, Ukraine.,University of Rzeszow, Zelwerowicza 4, 35-601, Rzeszow, Poland
| | - Andriy A Sibirny
- Institute of Cell Biology, NAS of Ukraine, Drahomanov St, 14/16, 79005, Lviv, Ukraine. .,University of Rzeszow, Zelwerowicza 4, 35-601, Rzeszow, Poland.
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21
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Svetlitchnyi VA, Svetlichnaya TP, Falkenhan DA, Swinnen S, Knopp D, Läufer A. Direct conversion of cellulose to L-lactic acid by a novel thermophilic Caldicellulosiruptor strain. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:44. [PMID: 35501875 PMCID: PMC9063331 DOI: 10.1186/s13068-022-02137-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 04/14/2022] [Indexed: 11/18/2022]
Abstract
Background Consolidated bioprocessing (CBP) of lignocellulosic biomass to l-lactic acid using thermophilic cellulolytic/hemicellulolytic bacteria provides a promising solution for efficient lignocellulose conversion without the need for additional cellulolytic/hemicellulolytic enzymes. Most studies on the mesophilic and thermophilic CBP of lignocellulose to lactic acid concentrate on cultivation of non-cellulolytic mesophilic and thermophilic bacteria at temperatures of 30–55 °C with external addition of cellulases/hemicellulases for saccharification of substrates. Results l-Lactic acid was generated by fermenting microcrystalline cellulose or lignocellulosic substrates with a novel thermophilic anaerobic bacterium Caldicellulosiruptor sp. DIB 104C without adding externally produced cellulolytic/hemicellulolytic enzymes. Selection of this novel bacterium strain for lactic acid production is described as well as the adaptive evolution towards increasing the l-lactic acid concentration from 6 to 70 g/l on microcrystalline cellulose. The evolved strains grown on microcrystalline cellulose show a maximum lactic acid production rate of 1.0 g/l*h and a lactic acid ratio in the total organic fermentation products of 96 wt%. The enantiomeric purity of the l-lactic acid generated is 99.4%. In addition, the lactic acid production by these strains on several other types of cellulose and lignocellulosic feedstocks is also reported. Conclusions The evolved strains originating from Caldicellulosiruptor sp. DIB 104C were capable of producing unexpectedly large amounts of l-lactic acid from microcrystalline cellulose in fermenters. These strains produce l-lactic acid also from lignocellulosic feedstocks and thus represent an ideal starting point for development of a highly integrated commercial l-lactic acid production process from such feedstocks.
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Affiliation(s)
| | | | | | - Steve Swinnen
- BluCon Biotech GmbH, Nattermannallee 1, 50829, Cologne, Germany
| | - Daniela Knopp
- BluCon Biotech GmbH, Nattermannallee 1, 50829, Cologne, Germany
| | - Albrecht Läufer
- BluCon Biotech GmbH, Nattermannallee 1, 50829, Cologne, Germany
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22
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Cardoon Hydrolysate Detoxification by Activated Carbon or Membranes System for Bioethanol Production. ENERGIES 2022. [DOI: 10.3390/en15061993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Advanced biofuels incorporation into the transportation sector, particularly cellulosic bioethanol, is crucial for attaining carbon neutrality by 2050, contributing to climate changes mitigation and wastes minimization. The world needs biofuel to be commercially available to tackle the socioeconomic challenges coming from the continued use of fossil fuels. Cynara cardunculus (cardoon) is a cheap lignocellulosic raw biomass that easily grows in Mediterraneous soils and is a potential renewable resource for a biorefinery. This work aimed to study the bioethanol production from cardoon hemicellulosic hydrolysates, which originated from dilute sulfuric acid hydrolysis pretreatment. A detoxification step to remove released microbial fermentative inhibitors was evaluated by using both activated carbon adsorption and a nanofiltration membrane system. The Scheffersomyces stipitis CBS5773 yeast and the modified Escherichia coli MS04 fermentation performances at different experimental conditions were compared. The promising results with E. coli, using detoxified cardoon by membrane nanofiltration, led to a bioethanol volumetric productivity of 0.30 g·L−1·h−1, with a conversion efficiency of 94.5%. Regarding the S. stipitis, in similar fermentation conditions, volumetric productivity of 0.091 g·L−1·h−1 with a conversion efficiency of 64.9% was obtained. Concluding, the production of bioethanol through detoxification of hemicellulosic cardoon hydrolysate presents a suitable alternative for the production of second-generation bioethanol, especially using the modified E. coli.
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23
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Miah R, Siddiqa A, Chakraborty U, Tuli JF, Barman NK, Uddin A, Aziz T, Sharif N, Dey SK, Yamada M, Talukder AA. Development of high temperature simultaneous saccharification and fermentation by thermosensitive Saccharomyces cerevisiae and Bacillus amyloliquefaciens. Sci Rep 2022; 12:3630. [PMID: 35256663 PMCID: PMC8901927 DOI: 10.1038/s41598-022-07589-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 01/27/2022] [Indexed: 11/09/2022] Open
Abstract
Scarcity of energy and pollution are two major challenges that have become a threat to all living things worldwide. Bioethanol is a renewable, ecological-friendly clean energy that may be utilized to address these issues. This study aimed to develop simultaneous saccharification and fermentation (SSF) process through high temperature-substrate adaptation and co-cultivation of S. cerevisiae with other potential amylolytic strains. In this study, we adapted our previously screened thermosensitive Saccharomyces cerevisiae Dj-3 strain up-to 42 °C and also screened three potential thermotolerant amylolytic strains based on their starch utilization capability. We performed SSF fermentation at high temperature by adapted Dj-3 and amylolytic strains using 10.0% starch feedstock. Interestingly, we observed significant ethanol concentration [3.86% (v/v)] from high temperature simultaneous saccharification and fermentation (HSSF) of adapted Bacillus amyloliquefaciens (C-7) and Dj-3. We attribute the significant ethanol concentration from starch of this HSSF process to C-7’s high levels of glucoamylase activity (4.01 U/ml/min) after adaptation in starch (up-to 42 °C) as well as Dj-3's strong glucose fermentation capacity and also their ethanol stress tolerance capability. This study suggests the significant feasibility of our HSSF process.
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Affiliation(s)
- Roni Miah
- Department of Microbiology, Jahangirnagar University, Dhaka, 1342, Bangladesh.,Department of Biological Chemistry, Yamaguchi University, Yamaguchi, 755, Japan
| | - Ayesha Siddiqa
- Department of Microbiology, Jahangirnagar University, Dhaka, 1342, Bangladesh.,Department of Biological Chemistry, Yamaguchi University, Yamaguchi, 755, Japan
| | | | | | - Noyon Kumar Barman
- Department of Microbiology, Jahangirnagar University, Dhaka, 1342, Bangladesh
| | - Aukhil Uddin
- Department of Microbiology, Jahangirnagar University, Dhaka, 1342, Bangladesh
| | - Tareque Aziz
- Department of Microbiology, Jahangirnagar University, Dhaka, 1342, Bangladesh
| | - Nadim Sharif
- Department of Microbiology, Jahangirnagar University, Dhaka, 1342, Bangladesh
| | - Shuvra Kanti Dey
- Department of Microbiology, Jahangirnagar University, Dhaka, 1342, Bangladesh
| | - Mamoru Yamada
- Department of Biological Chemistry, Yamaguchi University, Yamaguchi, 755, Japan
| | - Ali Azam Talukder
- Department of Microbiology, Jahangirnagar University, Dhaka, 1342, Bangladesh. .,Department of Biological Chemistry, Yamaguchi University, Yamaguchi, 755, Japan.
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24
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van Aalst AC, de Valk SC, van Gulik WM, Jansen ML, Pronk JT, Mans R. Pathway engineering strategies for improved product yield in yeast-based industrial ethanol production. Synth Syst Biotechnol 2022; 7:554-566. [PMID: 35128088 PMCID: PMC8792080 DOI: 10.1016/j.synbio.2021.12.010] [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: 11/29/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/16/2022] Open
Abstract
Product yield on carbohydrate feedstocks is a key performance indicator for industrial ethanol production with the yeast Saccharomyces cerevisiae. This paper reviews pathway engineering strategies for improving ethanol yield on glucose and/or sucrose in anaerobic cultures of this yeast by altering the ratio of ethanol production, yeast growth and glycerol formation. Particular attention is paid to strategies aimed at altering energy coupling of alcoholic fermentation and to strategies for altering redox-cofactor coupling in carbon and nitrogen metabolism that aim to reduce or eliminate the role of glycerol formation in anaerobic redox metabolism. In addition to providing an overview of scientific advances we discuss context dependency, theoretical impact and potential for industrial application of different proposed and developed strategies.
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Affiliation(s)
- Aafke C.A. van Aalst
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Sophie C. de Valk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Walter M. van Gulik
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Mickel L.A. Jansen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613, AX Delft, the Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Robert Mans
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ Delft, the Netherlands
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25
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Raj T, Chandrasekhar K, Naresh Kumar A, Rajesh Banu J, Yoon JJ, Kant Bhatia S, Yang YH, Varjani S, Kim SH. Recent advances in commercial biorefineries for lignocellulosic ethanol production: Current status, challenges and future perspectives. BIORESOURCE TECHNOLOGY 2022; 344:126292. [PMID: 34748984 DOI: 10.1016/j.biortech.2021.126292] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 05/26/2023]
Abstract
Cellulosic ethanol production has received global attention to use as transportation fuels with gasoline blending virtue of carbon benefits and decarbonization. However, due to changing feedstock composition, natural resistance, and a lack of cost-effective pretreatment and downstream processing, contemporary cellulosic ethanol biorefineries are facing major sustainability issues. As a result, we've outlined the global status of present cellulosic ethanol facilities, as well as main roadblocks and technical challenges for sustainable and commercial cellulosic ethanol production. Additionally, the article highlights the technical and non-technical barriers, various R&D advancements in biomass pretreatment, enzymatic hydrolysis, fermentation strategies that have been deliberated for low-cost sustainable fuel ethanol. Moreover, selection of a low-cost efficient pretreatment method, process simulation, unit integration, state-of-the-art in one pot saccharification and fermentation, system microbiology/ genetic engineering for robust strain development, and comprehensive techno-economic analysis are all major bottlenecks that must be considered for long-term ethanol production in the transportation sector.
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Affiliation(s)
- Tirath Raj
- School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - K Chandrasekhar
- School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - A Naresh Kumar
- Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742, USA
| | - J Rajesh Banu
- Department of Life Sciences, Central University of Tamil Nadu, Thiruvarur 610 005, India
| | - Jeong-Jun Yoon
- Green and Sustainable Materials R&D Department, Korea Institute of Industrial Technology (KITECH), Cheonan-si, Chungcheongnam-do 31056, Republic of Korea
| | - Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Yung-Hun Yang
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Sunita Varjani
- Gujarat Pollution Control Board, Gandhinagar, Gujarat 382 010, India
| | - Sang-Hyoun Kim
- School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea.
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26
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Chen X, Lu Z, Chen Y, Wu R, Luo Z, Lu Q, Guan N, Chen D. Deletion of the MBP1 Gene, Involved in the Cell Cycle, Affects Respiration and Pseudohyphal Differentiation in Saccharomyces cerevisiae. Microbiol Spectr 2021; 9:e0008821. [PMID: 34346754 PMCID: PMC8552743 DOI: 10.1128/spectrum.00088-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 05/03/2021] [Indexed: 11/20/2022] Open
Abstract
Mbp1p is a component of MBF (MluI cell cycle box binding factor, Mbp1p-Swi6p) and is well known to regulate the G1-S transition of the cell cycle. However, few studies have provided clues regarding its role in fermentation. This work aimed to recognize the function of the MBP1 gene in ethanol fermentation in a wild-type industrial Saccharomyces cerevisiae strain. MBP1 deletion caused an obvious decrease in the final ethanol concentration under oxygen-limited (without agitation), but not under aerobic, conditions (130 rpm). Furthermore, the mbp1Δ strain showed 84% and 35% decreases in respiration intensity under aerobic and oxygen-limited conditions, respectively. These findings indicate that MBP1 plays an important role in responding to variations in oxygen content and is involved in the regulation of respiration and fermentation. Unexpectedly, mbp1Δ also showed pseudohyphal growth, in which cells elongated and remained connected in a multicellular arrangement on yeast extract-peptone-dextrose (YPD) plates. In addition, mbp1Δ showed an increase in cell volume, associated with a decrease in the fraction of budded cells. These results provide more detailed information about the function of MBP1 and suggest some clues to efficiently improve ethanol production by industrially engineered yeast strains. IMPORTANCE Saccharomyces cerevisiae is an especially favorable organism used for ethanol production. However, inhibitors and high osmolarity conferred by fermentation broth, and high concentrations of ethanol as fermentation runs to completion, affect cell growth and ethanol production. Therefore, yeast strains with high performance, such as rapid growth, high tolerance, and high ethanol productivity, are highly desirable. Great efforts have been made to improve their performance by evolutionary engineering, and industrial strains may be a better start than laboratory ones for industrial-scale ethanol production. The significance of our research is uncovering the function of MBP1 in ethanol fermentation in a wild-type industrial S. cerevisiae strain, which may provide clues to engineer better-performance yeast in producing ethanol. Furthermore, the results that lacking MBP1 caused pseudohyphal growth on YPD plates could shed light on the development of xylose-fermenting S. cerevisiae, as using xylose as the sole carbon source also caused pseudohyphal growth.
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Affiliation(s)
- Xiaoling Chen
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, People’s Republic of China
| | - Zhilong Lu
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, People’s Republic of China
| | - Ying Chen
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, People’s Republic of China
| | - Renzhi Wu
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, People’s Republic of China
| | - Zhenzhen Luo
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, People’s Republic of China
| | - Qi Lu
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, People’s Republic of China
| | - Ni Guan
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, People’s Republic of China
| | - Dong Chen
- National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, Guangxi, People’s Republic of China
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Adebami GE, Kuila A, Ajunwa OM, Fasiku SA, Asemoloye MD. Genetics and metabolic engineering of yeast strains for efficient ethanol production. J FOOD PROCESS ENG 2021. [DOI: 10.1111/jfpe.13798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
| | - Arindam Kuila
- Department of Bioscience and Biotechnology Banasthali University Vanasthali India
| | - Obinna M. Ajunwa
- Department of Microbiology Modibbo Adama University of Technology Yola Nigeria
| | - Samuel A. Fasiku
- Department of Biological Sciences Ajayi Crowther University Oyo Nigeria
| | - Michael D. Asemoloye
- Department of Pharmaceutical Science and Technology Tianjin University Tianjin China
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28
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Nwaefuna AE, Rumbold K, Boekhout T, Zhou N. Bioethanolic yeasts from dung beetles: tapping the potential of extremophilic yeasts for improvement of lignocellulolytic feedstock fermentation. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:86. [PMID: 33827664 PMCID: PMC8028181 DOI: 10.1186/s13068-021-01940-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 03/27/2021] [Indexed: 05/10/2023]
Abstract
Bioethanol from abundant and inexpensive agricultural and industrial wastes possesses the potential to reduce greenhouse gas emissions. Bioethanol as renewable fuel addresses elevated production costs, as well as food security concerns. Although technical advancements in simultaneous saccharification and fermentation have reduced the cost of production, one major drawback of this technology is that the pre-treatment process creates environmental stressors inhibitory to fermentative yeasts subsequently reducing bioethanol productivity. Robust fermentative yeasts with extreme stress tolerance remain limited. This review presents the potential of dung beetles from pristine and unexplored environments as an attractive source of extremophilic bioethanolic yeasts. Dung beetles survive on a recalcitrant lignocellulose-rich diet suggesting the presence of symbiotic yeasts with a cellulolytic potential. Dung beetles inhabiting extreme stress environments have the potential to harbour yeasts with the ability to withstand inhibitory environmental stresses typically associated with bioethanol production. The review further discusses established methods used to isolate bioethanolic yeasts, from dung beetles.
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Affiliation(s)
- Anita Ejiro Nwaefuna
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Private Bag 16, Palapye, Botswana
| | - Karl Rumbold
- Industrial Microbiology and Biotechnology Laboratory, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
| | - Teun Boekhout
- Westerdijk Fungal Biodiversity Institute, 3584CT Utrecht, the Netherlands
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, 1098 SM Amsterdam, the Netherlands
| | - Nerve Zhou
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Private Bag 16, Palapye, Botswana
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29
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Advanced Bioethanol Production: From Novel Raw Materials to Integrated Biorefineries. Processes (Basel) 2021. [DOI: 10.3390/pr9020206] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The production of so-called advanced bioethanol offers several advantages compared to traditional bioethanol production processes in terms of sustainability criteria. This includes, for instance, the use of nonfood crops or residual biomass as raw material and a higher potential for reducing greenhouse gas emissions. The present review focuses on the recent progress related to the production of advanced bioethanol, (i) highlighting current results from using novel biomass sources such as the organic fraction of municipal solid waste and certain industrial residues (e.g., residues from the paper, food, and beverage industries); (ii) describing new developments in pretreatment technologies for the fractionation and conversion of lignocellulosic biomass, such as the bioextrusion process or the use of novel ionic liquids; (iii) listing the use of new enzyme catalysts and microbial strains during saccharification and fermentation processes. Furthermore, the most promising biorefinery approaches that will contribute to the cost-competitiveness of advanced bioethanol production processes are also discussed, focusing on innovative technologies and applications that can contribute to achieve a more sustainable and effective utilization of all biomass fractions. Special attention is given to integrated strategies such as lignocellulose-based biorefineries for the simultaneous production of bioethanol and other high added value bioproducts.
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30
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Xu M, Tremblay PL, Ding R, Xiao J, Wang J, Kang Y, Zhang T. Photo-augmented PHB production from CO 2 or fructose by Cupriavidus necator and shape-optimized CdS nanorods. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 753:142050. [PMID: 32898811 DOI: 10.1016/j.scitotenv.2020.142050] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/27/2020] [Accepted: 08/27/2020] [Indexed: 06/11/2023]
Abstract
Particulate photocatalysts developed for the solar energy-driven reduction of the greenhouse gas CO2 have a small product range and low specificity. Hybrid photosynthesis expands the number of products with photocatalysts harvesting sunlight and transferring charges to microbes harboring versatile metabolisms for bioproduction. Besides CO2, abiotic photocatalysts have been employed to increase microbial production yields of reduced compounds from organic carbon substrates. Most single-reactor hybrid photosynthesis systems comprise CdS assembled in situ by microbial activity. This approach limits optimization of the morphology, crystal structure, and crystallinity of CdS for higher performance, which is usually done via synthesis methods incompatible with life. Here, shape and activity optimized CdS nanorods were hydrothermally produced and subsequently applied to Cupriavidus necator for the heterotrophic and autotrophic production of the bioplastic polyhydroxybutyrate (PHB). C. necator with CdS NR under light produced 1.5 times more PHB when compared to the same bacterium with suboptimal commercially-available CdS. Illuminated C. necator with CdS NR synthesized 1.41 g PHB from fructose over 120 h and 28 mg PHB from CO2 over 48 h. Interestingly, the beneficial effect of CdS NR was specific to C. necator as the metabolism of other microbes often employed for bioproduction including yeast and bacteria was negatively impacted. These results demonstrate that hybrid photosynthesis is more productive when the photocatalyst characteristics are optimized via a separated synthesis process prior to being coupled with microbes. Furthermore, bioproduction improvement by CdS-based photocatalyst requires specific microbial species highlighting the importance of screening efforts for the development of performant hybrid photosynthesis.
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Affiliation(s)
- Mengying Xu
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China; School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China
| | - Pier-Luc Tremblay
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China; School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China
| | - Ran Ding
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China; School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China
| | - Jianxun Xiao
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China; School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China
| | - Junting Wang
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China; School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China
| | - Yu Kang
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China; School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China
| | - Tian Zhang
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China; School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
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31
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Lehenberger M, Benkert M, Biedermann PHW. Ethanol-Enriched Substrate Facilitates Ambrosia Beetle Fungi, but Inhibits Their Pathogens and Fungal Symbionts of Bark Beetles. Front Microbiol 2021; 11:590111. [PMID: 33519728 PMCID: PMC7838545 DOI: 10.3389/fmicb.2020.590111] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/16/2020] [Indexed: 11/26/2022] Open
Abstract
Bark beetles (sensu lato) colonize woody tissues like phloem or xylem and are associated with a broad range of micro-organisms. Specific fungi in the ascomycete orders Hypocreales, Microascales and Ophistomatales as well as the basidiomycete Russulales have been found to be of high importance for successful tree colonization and reproduction in many species. While fungal mutualisms are facultative for most phloem-colonizing bark beetles (sensu stricto), xylem-colonizing ambrosia beetles are long known to obligatorily depend on mutualistic fungi for nutrition of adults and larvae. Recently, a defensive role of fungal mutualists for their ambrosia beetle hosts was revealed: Few tested mutualists outcompeted other beetle-antagonistic fungi by their ability to produce, detoxify and metabolize ethanol, which is naturally occurring in stressed and/or dying trees that many ambrosia beetle species preferentially colonize. Here, we aim to test (i) how widespread beneficial effects of ethanol are among the independently evolved lineages of ambrosia beetle fungal mutualists and (ii) whether it is also present in common fungal symbionts of two bark beetle species (Ips typographus, Dendroctonus ponderosae) and some general fungal antagonists of bark and ambrosia beetle species. The majority of mutualistic ambrosia beetle fungi tested benefited (or at least were not harmed) by the presence of ethanol in terms of growth parameters (e.g., biomass), whereas fungal antagonists were inhibited. This confirms the competitive advantage of nutritional mutualists in the beetle’s preferred, ethanol-containing host material. Even though most bark beetle fungi are found in the same phylogenetic lineages and ancestral to the ambrosia beetle (sensu stricto) fungi, most of them were highly negatively affected by ethanol and only a nutritional mutualist of Dendroctonus ponderosae benefited, however. This suggests that ethanol tolerance is a derived trait in nutritional fungal mutualists, particularly in ambrosia beetles that show cooperative farming of their fungi.
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Affiliation(s)
- Maximilian Lehenberger
- Research Group Insect-Fungus Symbiosis, Department of Animal Ecology and Tropical Biology, University of Würzburg, Würzburg, Germany
| | - Markus Benkert
- Research Group Insect-Fungus Symbiosis, Department of Animal Ecology and Tropical Biology, University of Würzburg, Würzburg, Germany
| | - Peter H W Biedermann
- Research Group Insect-Fungus Symbiosis, Department of Animal Ecology and Tropical Biology, University of Würzburg, Würzburg, Germany.,Chair of Forest Entomology and Protection, University of Freiburg, Freiburg im Breisgau, Germany
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32
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Ruchala J, Sibirny AA. Pentose metabolism and conversion to biofuels and high-value chemicals in yeasts. FEMS Microbiol Rev 2020; 45:6034013. [PMID: 33316044 DOI: 10.1093/femsre/fuaa069] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/09/2020] [Indexed: 12/15/2022] Open
Abstract
Pentose sugars are widespread in nature and two of them, D-xylose and L-arabinose belong to the most abundant sugars being the second and third by abundance sugars in dry plant biomass (lignocellulose) and in general on planet. Therefore, it is not surprising that metabolism and bioconversion of these pentoses attract much attention. Several different pathways of D-xylose and L-arabinose catabolism in bacteria and yeasts are known. There are even more common and really ubiquitous though not so abundant pentoses, D-ribose and 2-deoxy-D-ribose, the constituents of all living cells. Thus, ribose metabolism is example of endogenous metabolism whereas metabolism of other pentoses, including xylose and L-arabinose, represents examples of the metabolism of foreign exogenous compounds which normally are not constituents of yeast cells. As a rule, pentose degradation by the wild-type strains of microorganisms does not lead to accumulation of high amounts of valuable substances; however, productive strains have been obtained by random selection and metabolic engineering. There are numerous reviews on xylose and (less) L-arabinose metabolism and conversion to high value substances; however, they mostly are devoted to bacteria or the yeast Saccharomyces cerevisiae. This review is devoted to reviewing pentose metabolism and bioconversion mostly in non-conventional yeasts, which naturally metabolize xylose. Pentose metabolism in the recombinant strains of S. cerevisiae is also considered for comparison. The available data on ribose, xylose, L-arabinose transport, metabolism, regulation of these processes, interaction with glucose catabolism and construction of the productive strains of high-value chemicals or pentose (ribose) itself are described. In addition, genome studies of the natural xylose metabolizing yeasts and available tools for their molecular research are reviewed. Metabolism of other pentoses (2-deoxyribose, D-arabinose, lyxose) is briefly reviewed.
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Affiliation(s)
- Justyna Ruchala
- Department of Microbiology and Molecular Genetics, University of Rzeszow, Zelwerowicza 4, Rzeszow 35-601, Poland.,Department of Molecular Genetics and Biotechnology, Institute of Cell Biology NAS of Ukraine, Drahomanov Street, 14/16, Lviv 79005, Ukraine
| | - Andriy A Sibirny
- Department of Microbiology and Molecular Genetics, University of Rzeszow, Zelwerowicza 4, Rzeszow 35-601, Poland.,Department of Molecular Genetics and Biotechnology, Institute of Cell Biology NAS of Ukraine, Drahomanov Street, 14/16, Lviv 79005, Ukraine
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33
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Ceccato-Antonini SR, Covre EA. From baker's yeast to genetically modified budding yeasts: the scientific evolution of bioethanol industry from sugarcane. FEMS Yeast Res 2020; 20:6021367. [PMID: 33406233 DOI: 10.1093/femsyr/foaa065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 12/02/2020] [Indexed: 12/22/2022] Open
Abstract
The peculiarities of Brazilian fuel ethanol fermentation allow the entry of native yeasts that may dominate over the starter strains of Saccharomyces cerevisiae and persist throughout the sugarcane harvest. The switch from the use of baker's yeast as starter to selected budding yeasts obtained by a selective pressure strategy was followed by a wealth of genomic information that enabled the understanding of the superiority of selected yeast strains. This review describes how the process of yeast selection evolved in the sugarcane-based bioethanol industry, the selection criteria and recent advances in genomics that could advance the fermentation process. The prospective use of genetically modified yeast strains, specially designed for increased robustness and product yield, with special emphasis on those obtained by the CRISPR (clustered regularly interspaced palindromic repeats)-Cas9 (CRISPR-associated protein 9) genome-editing approach, is discussed as a possible solution to confer higher performance and stability to the fermentation process for fuel ethanol production.
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Affiliation(s)
- Sandra Regina Ceccato-Antonini
- Laboratory of Agricultural and Molecular Microbiology, Dept Tecnologia Agroindustrial e Socioeconomia Rural, Centro de Ciências Agrárias, Universidade Federal de São Carlos, Via Anhanguera, km 174, 13600-970 Araras, São Paulo State, Brazil
| | - Elizabete Aparecida Covre
- Laboratory of Agricultural and Molecular Microbiology, Dept Tecnologia Agroindustrial e Socioeconomia Rural, Centro de Ciências Agrárias, Universidade Federal de São Carlos, Via Anhanguera, km 174, 13600-970 Araras, São Paulo State, Brazil
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34
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Zahoor A, Messerschmidt K, Boecker S, Klamt S. ATPase-based implementation of enforced ATP wasting in Saccharomyces cerevisiae for improved ethanol production. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:185. [PMID: 33292464 PMCID: PMC7654063 DOI: 10.1186/s13068-020-01822-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 10/23/2020] [Indexed: 05/06/2023]
Abstract
BACKGROUND Enforced ATP wasting has been recognized as a promising metabolic engineering strategy to enhance the microbial production of metabolites that are coupled to ATP generation. It also appears to be a suitable approach to improve production of ethanol by Saccharomyces cerevisiae. In the present study, we constructed different S. cerevisiae strains with heterologous expression of genes of the ATP-hydrolyzing F1-part of the ATPase enzyme to induce enforced ATP wasting and quantify the resulting effect on biomass and ethanol formation. RESULTS In contrast to genomic integration, we found that episomal expression of the αβγ subunits of the F1-ATPase genes of Escherichia coli in S. cerevisiae resulted in significantly increased ATPase activity, while neither genomic integration nor episomal expression of the β subunit from Trichoderma reesei could enhance ATPase activity. When grown in minimal medium under anaerobic growth-coupled conditions, the strains expressing E. coli's F1-ATPase genes showed significantly improved ethanol yield (increase of 10% compared to the control strain). However, elevated product formation reduces biomass formation and, therefore, volumetric productivity. We demonstrate that this negative effect can be overcome under growth-decoupled (nitrogen-starved) operation with high and constant biomass concentration. Under these conditions, which mimic the second (production) phase of a two-stage fermentation process, the ATPase-expressing strains showed significant improvement in volumetric productivity (up to 111%) compared to the control strain. CONCLUSIONS Our study shows that expression of genes of the F1-portion of E. coli's ATPase induces ATPase activity in S. cerevisiae and can be a promising way to improve ethanol production. This ATP-wasting strategy can be easily applied to other metabolites of interest, whose formation is coupled to ATP generation.
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Affiliation(s)
- Ahmed Zahoor
- Analysis and Redesign of Biological Networks, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Katrin Messerschmidt
- Analysis and Redesign of Biological Networks, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Simon Boecker
- Analysis and Redesign of Biological Networks, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Steffen Klamt
- Analysis and Redesign of Biological Networks, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
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Hybrid neural network modeling and particle swarm optimization for improved ethanol production from cashew apple juice. Bioprocess Biosyst Eng 2020; 44:329-342. [PMID: 32995977 DOI: 10.1007/s00449-020-02445-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 09/09/2020] [Indexed: 10/23/2022]
Abstract
A hybrid neural model (HNM) and particle swarm optimization (PSO) was used to optimize ethanol production by a flocculating yeast, grown on cashew apple juice. HNM was obtained by combining artificial neural network (ANN), which predicted reaction specific rates, to mass balance equations for substrate (S), product and biomass (X) concentration, being an alternative method for predicting the behavior of complex systems. ANNs training was conducted using an experimental set of data of X and S, temperature and stirring speed. The HNM was statistically validated against a new dataset, being capable of representing the system behavior. The model was optimized based on a multiobjective function relating efficiency and productivity by applying the PSO. Optimal estimated conditions were: S0 = 127 g L-1, X0 = 5.8 g L-1, 35 °C and 111 rpm. In this condition, an efficiency of 91.5% with a productivity of 8.0 g L-1 h-1 was obtained at approximately 7 h of fermentation.
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Perez G, Debernardis F, Boido E, Carrau F. Simultaneous identification to monitor consortia strain dynamics of four biofuel yeast species during fermentation. J Ind Microbiol Biotechnol 2020; 47:1133-1140. [PMID: 32965544 DOI: 10.1007/s10295-020-02310-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 09/07/2020] [Indexed: 11/28/2022]
Abstract
Mixed strain dynamics are still not well or easily monitored although recently molecular identification methods have improved our knowledge. This study used a chromogenic differential plating medium that allows the discrimination of four of the main selected biofuel strains that are currently under development for ethanol production from cellulosic hydrolysates. Complete fermentation of hexoses and xylose was obtained with a yeast consortium composed of Spathaspora passalidarum, Scheffersomyces stipitis, Candida akabanensis and Saccharomyces cerevisiae. The results showed that C.akabanensis excessively dominated consortium balance. Reducing its inoculum from 33 to 4.8% improved population strain balance and fermentation efficiency. Comparison of the consortia with single strain fermentations showed that it optimize sugar consumption and ethanol yields. This simple and cheap method also has advantages compared with molecular methods, as the yeast strains do not need to be genetically marked and identified cell proportions are probably active in the fermentation system as compared to DNA determination methods.
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Affiliation(s)
- Gabriel Perez
- Área Enología y Biotecnología de la Fermentación, Departamento Ciencia y Tecnología Alimentos, Facultad de Quimica, Universidad de la Republica, 11800, Montevideo, Uruguay
| | - Florencia Debernardis
- Área Enología y Biotecnología de la Fermentación, Departamento Ciencia y Tecnología Alimentos, Facultad de Quimica, Universidad de la Republica, 11800, Montevideo, Uruguay
| | - Eduardo Boido
- Área Enología y Biotecnología de la Fermentación, Departamento Ciencia y Tecnología Alimentos, Facultad de Quimica, Universidad de la Republica, 11800, Montevideo, Uruguay
| | - Francisco Carrau
- Área Enología y Biotecnología de la Fermentación, Departamento Ciencia y Tecnología Alimentos, Facultad de Quimica, Universidad de la Republica, 11800, Montevideo, Uruguay.
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Pinheiro ÁDT, Barros EM, Rocha LA, Ponte VMDR, de Macedo AC, Rocha MVP, Gonçalves LRB. Optimization and scale-up of ethanol production by a flocculent yeast using cashew apple juice as feedstock. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2020. [DOI: 10.1007/s43153-020-00068-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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The Xylose Metabolizing Yeast Spathaspora passalidarum is a Promising Genetic Treasure for Improving Bioethanol Production. FERMENTATION-BASEL 2020. [DOI: 10.3390/fermentation6010033] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Currently, the fermentation technology for recycling agriculture waste for generation of alternative renewable biofuels is getting more and more attention because of the environmental merits of biofuels for decreasing the rapid rise of greenhouse gas effects compared to petrochemical, keeping in mind the increase of petrol cost and the exhaustion of limited petroleum resources. One of widely used biofuels is bioethanol, and the use of yeasts for commercial fermentation of cellulosic and hemicellulosic agricultural biomasses is one of the growing biotechnological trends for bioethanol production. Effective fermentation and assimilation of xylose, the major pentose sugar element of plant cell walls and the second most abundant carbohydrate, is a bottleneck step towards a robust biofuel production from agricultural waste materials. Hence, several attempts were implemented to engineer the conventional Saccharomyces cerevisiae yeast to transport and ferment xylose because naturally it does not use xylose, using genetic materials of Pichia stipitis, the pioneer native xylose fermenting yeast. Recently, the nonconventional yeast Spathaspora passalidarum appeared as a founder member of a new small group of yeasts that, like Pichia stipitis, can utilize and ferment xylose. Therefore, the understanding of the molecular mechanisms regulating the xylose assimilation in such pentose fermenting yeasts will enable us to eliminate the obstacles in the biofuels pipeline, and to develop industrial strains by means of genetic engineering to increase the availability of renewable biofuel products from agricultural biomass. In this review, we will highlight the recent advances in the field of native xylose metabolizing yeasts, with special emphasis on S. passalidarum for improving bioethanol production.
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Wang BT, Hu S, Yu XY, Jin L, Zhu YJ, Jin FJ. Studies of Cellulose and Starch Utilization and the Regulatory Mechanisms of Related Enzymes in Fungi. Polymers (Basel) 2020; 12:polym12030530. [PMID: 32121667 PMCID: PMC7182937 DOI: 10.3390/polym12030530] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/14/2020] [Accepted: 02/16/2020] [Indexed: 12/24/2022] Open
Abstract
Polysaccharides are biopolymers made up of a large number of monosaccharides joined together by glycosidic bonds. Polysaccharides are widely distributed in nature: Some, such as peptidoglycan and cellulose, are the components that make up the cell walls of bacteria and plants, and some, such as starch and glycogen, are used as carbohydrate storage in plants and animals. Fungi exist in a variety of natural environments and can exploit a wide range of carbon sources. They play a crucial role in the global carbon cycle because of their ability to break down plant biomass, which is composed primarily of cell wall polysaccharides, including cellulose, hemicellulose, and pectin. Fungi produce a variety of enzymes that in combination degrade cell wall polysaccharides into different monosaccharides. Starch, the main component of grain, is also a polysaccharide that can be broken down into monosaccharides by fungi. These monosaccharides can be used for energy or as precursors for the biosynthesis of biomolecules through a series of enzymatic reactions. Industrial fermentation by microbes has been widely used to produce traditional foods, beverages, and biofuels from starch and to a lesser extent plant biomass. This review focuses on the degradation and utilization of plant homopolysaccharides, cellulose and starch; summarizes the activities of the enzymes involved and the regulation of the induction of the enzymes in well-studied filamentous fungi.
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