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Wang K, Zhao W, Lin L, Wang T, Wei P, Ledesma-Amaro R, Zhang AH, Ji XJ. A robust soft sensor based on artificial neural network for monitoring microbial lipid fermentation processes using Yarrowia lipolytica. Biotechnol Bioeng 2023; 120:1015-1025. [PMID: 36522163 DOI: 10.1002/bit.28310] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/07/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Microbial oils produced by Yarrowia lipolytica offer an environmentally friendly and sustainable alternative to petroleum as well as traditional lipids from animals and plants. The accurate measurement of fermentation parameters, including the substrate concentration, dry cell weight, and lipid accumulation, is the foundation of process control, which is indispensable for industrial lipid production. However, it remains a great challenge to measure the complex parameters online during the lipid fermentation process, which is nonlinear, multivariate, and characterized by strong coupling. As a type of AI technology, the artificial neural network model is a powerful tool for handling extremely complex problems, and it can be employed to develop a soft sensor to monitor the microbial lipid fermentation process of Y. lipolytica. In this study, we first analyzed and emphasized the volume of sodium hydroxide and dissolved oxygen concentration as central parameters of the fermentation process. Then, a soft sensor based on a four-input artificial neural network model was developed, in which the input variables were fermentation time, dissolved oxygen concentration, initial glucose concentration, and additional volume of sodium hydroxide. This provides the possibility of online monitoring of dry cell weight, glucose concentration, and lipid production with high accuracy, which can be extended to similar fermentation processes characterized by the addition of bases or acids, as well as changes of the dissolved oxygen concentration.
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Affiliation(s)
- Kaifeng Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, People's Republic of China
| | - Wenyang Zhao
- Institute of Network and Cloud Computing Technology, College of Computer Science and Technology, Nanjing Tech University, Nanjing, People's Republic of China
| | - Lu Lin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, People's Republic of China
| | - Tianjing Wang
- Institute of Network and Cloud Computing Technology, College of Computer Science and Technology, Nanjing Tech University, Nanjing, People's Republic of China
| | - Ping Wei
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, People's Republic of China
| | - Rodrigo Ledesma-Amaro
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London, UK
| | - Ai-Hui Zhang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People's Republic of China
| | - Xiao-Jun Ji
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, People's Republic of China
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2
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Tadioto V, Deoti JR, Müller C, de Souza BR, Fogolari O, Purificação M, Giehl A, Deoti L, Lucaroni AC, Matsushika A, Treichel H, Stambuk BU, Alves Junior SL. Prospecting and engineering yeasts for ethanol production under inhibitory conditions: an experimental design analysis. Bioprocess Biosyst Eng 2022:10.1007/s00449-022-02812-x. [DOI: 10.1007/s00449-022-02812-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 11/09/2022] [Indexed: 11/25/2022]
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3
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Synergistic effects of inhibitors and osmotic stress during high gravity bioethanol production from steam-exploded lignocellulosic feedstocks. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2022.102414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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4
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Lima CS, Neitzel T, Pirolla R, Dos Santos LV, Lenczak JL, Roberto IC, Rocha GJM. Metabolomic profiling of Spathaspora passalidarum fermentations reveals mechanisms that overcome hemicellulose hydrolysate inhibitors. Appl Microbiol Biotechnol 2022; 106:4075-4089. [PMID: 35622124 DOI: 10.1007/s00253-022-11987-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: 08/09/2021] [Revised: 04/21/2022] [Accepted: 05/17/2022] [Indexed: 11/30/2022]
Abstract
Understanding the mechanisms involved in tolerance to inhibitors is the first step in developing robust yeasts for industrial second-generation ethanol (E2G) production. Here, we used ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) and MetaboAnalyst 4.0 for analysis of MS data to examine the changes in the metabolic profile of the yeast Spathaspora passalidarum during early fermentation of hemicellulosic hydrolysates containing high or low levels of inhibitors (referred to as control hydrolysate or CH and strategy hydrolysate or SH, respectively). During fermentation of SH, the maximum ethanol production was 16 g L-1 with a yield of 0.28 g g-1 and productivity of 0.22 g L-1 h-1, whereas maximum ethanol production in CH fermentation was 1.74 g L-1 with a yield of 0.11 g g-1 and productivity of 0.01 g L-1 h-1. The high level of inhibitors in CH induced complex physiological and biochemical responses related to stress tolerance in S. passalidarum. This yeast converted compounds with aldehyde groups (hydroxymethylfurfural, furfural, 4-hydroxybenzaldehyde, syringaldehyde, and vanillin) into less toxic compounds, and inhibitors were found to reduce cell viability and ethanol production. Intracellularly, high levels of inhibitors altered the energy homeostasis and redox balance, resulting in lower levels of ATP and NADPH, while that of glycolytic, pentose phosphate, and tricarboxylic acid (TCA) cycle pathways were the most affected, being the catabolism of glucogenic amino acids, the main cellular response to inhibitor-induced stress. This metabolomic investigation reveals interesting targets for metabolic engineering of ethanologenic yeast strains tolerant against multiple inhibitors for E2G production. KEY POINTS: • Inhibitors in the hydrolysates affected the yeast's redox balance and energy status. • Inhibitors altered the glycolytic, pentose phosphate, TCA cycle and amino acid pathways. • S. passalidarum converted aldehyde groups into less toxic compounds.
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Affiliation(s)
- Cleilton Santos Lima
- Department of Biotechnology, Engineering College of Lorena, University of São Paulo (USP), Estrada Municipal Do Campinho, s/n, Campinho, Lorena, SP, 12602-810, Brazil. .,Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Rua Giuseppe Máximo Scolfaro 10.000, Campinas, SP, 13083-100, Brazil.
| | - Thiago Neitzel
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Rua Giuseppe Máximo Scolfaro 10.000, Campinas, SP, 13083-100, Brazil.,Program in Bioenergy, Faculty of Food Engineering, State University of Campinas (UNICAMP), Rua Monteiro Lobato 80, Campinas, SP, 13083-862, Brazil
| | - Renan Pirolla
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Rua Giuseppe Máximo Scolfaro 10.000, Campinas, SP, 13083-100, Brazil
| | - Leandro Vieira Dos Santos
- Senai Innovation Institute for Biotechnology, São Paulo, SP, 01130-000, Brazil.,Genetics and Molecular Biology Graduate Program, Institute of Biology, State University of Campinas (UNICAMP), Rua Monteiro Lobato 255, Campinas, 13083-862, Brazil
| | - Jaciane Lutz Lenczak
- Department of Chemical Engineering and Food Engineering, University Campus - CTC, Federal University of Santa Catarina (UFSC), R. Do Biotério Central, Córrego Grande, s/n Florianópolis, SC, 88040-900, Brazil
| | - Inês Conceição Roberto
- Department of Biotechnology, Engineering College of Lorena, University of São Paulo (USP), Estrada Municipal Do Campinho, s/n, Campinho, Lorena, SP, 12602-810, Brazil
| | - George J M Rocha
- Department of Biotechnology, Engineering College of Lorena, University of São Paulo (USP), Estrada Municipal Do Campinho, s/n, Campinho, Lorena, SP, 12602-810, Brazil. .,Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Rua Giuseppe Máximo Scolfaro 10.000, Campinas, SP, 13083-100, Brazil.
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5
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How adaptive laboratory evolution can boost yeast tolerance to lignocellulosic hydrolyses. Curr Genet 2022; 68:319-342. [PMID: 35362784 DOI: 10.1007/s00294-022-01237-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/01/2022] [Accepted: 03/06/2022] [Indexed: 12/25/2022]
Abstract
The yeast Saccharomyces cerevisiae is an excellent candidate for establishing cell factories to convert lignocellulosic biomass into chemicals and fuels. To enable this technology, yeast robustness must be improved to withstand the fermentation inhibitors (e.g., weak organic acids, phenols, and furan aldehydes) resulting from biomass pretreatment and hydrolysis. Here, we discuss how evolution experiments performed in the lab, a method commonly known as adaptive laboratory evolution (ALE), may contribute to lifting yeast tolerance against the inhibitors of lignocellulosic hydrolysates (LCHs). The key is that, through the combination of whole-genome sequencing and reverse engineering, ALE provides a robust platform for discovering and testing adaptive alleles, allowing to explore the genetic underpinnings of yeast responses to LCHs. We review the insights gained from past evolution experiments with S. cerevisiae in LCH inhibitors and propose experimental designs to optimise the discovery of genetic variants adaptive to biomass toxicity. The knowledge gathered through ALE projects is envisaged as a roadmap to engineer superior yeast strains for biomass-based bioprocesses.
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Coprocessing Corn Germ Meal for Oil Recovery and Ethanol Production: A Process Model for Lipid-Producing Energy Crops. Processes (Basel) 2022. [DOI: 10.3390/pr10040661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Efforts to engineer high-productivity crops to accumulate oils in their vegetative tissue present the possibility of expanding biodiesel production. However, processing the new crops for lipid recovery and ethanol production from cell wall saccharides is challenging and expensive. In a previous study using corn germ meal as a model substrate, we reported that liquid hot water (LHW) pretreatment enriched the lipid concentration by 2.2 to 4.2 fold. This study investigated combining oil recovery with ethanol production by extracting oil following LHW and simultaneous saccharification and co-fermentation (SSCF) of the biomass. Corn germ meal was again used to model the oil-bearing energy crops. Pretreated germ meal hydrolysate or solids (160 and 180 °C for 10 min) were fermented, and lipids were extracted from both the spent fermentation whole broth and fermentation solids, which were recovered by centrifugation and convective drying. Lipid contents in spent fermentation solids increased 3.7 to 5.7 fold compared to the beginning germ meal. The highest lipid yield achieved after fermentation was 36.0 mg lipid g−1 raw biomass; the maximum relative amount of triacylglycerol (TAG) was 50.9% of extracted oil. Although the fermentation step increased the lipid concentration of the recovered solids, it did not improve the lipid yields of pretreated biomass and detrimentally affected oil compositions by increasing the relative concentrations of free fatty acids.
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Stovicek V, Dato L, Almqvist H, Schöpping M, Chekina K, Pedersen LE, Koza A, Figueira D, Tjosås F, Ferreira BS, Forster J, Lidén G, Borodina I. Rational and evolutionary engineering of Saccharomyces cerevisiae for production of dicarboxylic acids from lignocellulosic biomass and exploring genetic mechanisms of the yeast tolerance to the biomass hydrolysate. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:22. [PMID: 35219341 PMCID: PMC8882276 DOI: 10.1186/s13068-022-02121-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 02/12/2022] [Indexed: 12/13/2022]
Abstract
BACKGROUND Lignosulfonates are significant wood chemicals with a $700 million market, produced by sulfite pulping of wood. During the pulping process, spent sulfite liquor (SSL) is generated, which in addition to lignosulfonates contains hemicellulose-derived sugars-in case of hardwoods primarily the pentose sugar xylose. The pentoses are currently underutilized. If they could be converted into value-added chemicals, overall economic profitability of the process would increase. SSLs are typically very inhibitory to microorganisms, which presents a challenge for a biotechnological process. The aim of the present work was to develop a robust yeast strain able to convert xylose in SSL to carboxylic acids. RESULTS The industrial strain Ethanol Red of the yeast Saccharomyces cerevisiae was engineered for efficient utilization of xylose in a Eucalyptus globulus lignosulfonate stream at low pH using CRISPR/Cas genome editing and adaptive laboratory evolution. The engineered strain grew in synthetic medium with xylose as sole carbon source with maximum specific growth rate (µmax) of 0.28 1/h. Selected evolved strains utilized all carbon sources in the SSL at pH 3.5 and grew with µmax between 0.05 and 0.1 1/h depending on a nitrogen source supplement. Putative genetic determinants of the increased tolerance to the SSL were revealed by whole genome sequencing of the evolved strains. In particular, four top-candidate genes (SNG1, FIT3, FZF1 and CBP3) were identified along with other gene candidates with predicted important roles, based on the type and distribution of the mutations across different strains and especially the best performing ones. The developed strains were further engineered for production of dicarboxylic acids (succinic and malic acid) via overexpression of the reductive branch of the tricarboxylic acid cycle (TCA). The production strain produced 0.2 mol and 0.12 mol of malic acid and succinic acid, respectively, per mol of xylose present in the SSL. CONCLUSIONS The combined metabolic engineering and adaptive evolution approach provided a robust SSL-tolerant industrial strain that converts fermentable carbon content of the SSL feedstock into malic and succinic acids at low pH.in production yields reaching 0.1 mol and 0.065 mol per mol of total consumed carbon sources.. Moreover, our work suggests potential genetic background of the tolerance to the SSL stream pointing out potential gene targets for improving the tolerance to inhibitory industrial feedstocks.
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Affiliation(s)
- Vratislav Stovicek
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark
| | - Laura Dato
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark.,River Stone Biotech ApS, Fruebjergvej 3, 2100, Copenhagen, Denmark
| | - Henrik Almqvist
- Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00, Lund, Sweden
| | - Marie Schöpping
- Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00, Lund, Sweden.,Chr. Hansen A/S, Boge Alle 10-12, 2970, Hørsholm, Denmark.,Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Ksenia Chekina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark
| | - Lasse Ebdrup Pedersen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark
| | - Anna Koza
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark.,Chr. Hansen A/S, Boge Alle 10-12, 2970, Hørsholm, Denmark
| | - Diogo Figueira
- Biotrend S.A., Biocant Park Núcleo 04, Lote 2, 3060-197, Cantanhede, Portugal
| | - Freddy Tjosås
- Borregaard ApS, Hjalmar Wessels vei 6, 1721, Sarpsborg, Norway
| | | | - Jochen Forster
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark
| | - Gunnar Lidén
- Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00, Lund, Sweden
| | - Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark.
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8
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Brandt BA, García-Aparicio MDP, Görgens JF, van Zyl WH. Rational engineering of Saccharomyces cerevisiae towards improved tolerance to multiple inhibitors in lignocellulose fermentations. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:173. [PMID: 34454598 PMCID: PMC8403374 DOI: 10.1186/s13068-021-02021-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 08/20/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND The fermentation of lignocellulose hydrolysates to ethanol requires robust xylose-capable Saccharomyces cerevisiae strains able to operate in the presence of microbial inhibitory stresses. This study aimed at developing industrial S. cerevisiae strains with enhanced tolerance towards pretreatment-derived microbial inhibitors, by identifying novel gene combinations that confer resistance to multiple inhibitors (thus cumulative inhibitor resistance phenotype) with minimum impact on the xylose fermentation ability. The strategy consisted of multiple sequential delta-integrations of double-gene cassettes containing one gene conferring broad inhibitor tolerance (ARI1, PAD1 or TAL1) coupled with an inhibitor-specific gene (ADH6, FDH1 or ICT1). The performances of the transformants were compared with the parental strain in terms of biomass growth, ethanol yields and productivity, as well as detoxification capacities in a synthetic inhibitor cocktail, sugarcane bagasse hydrolysate as well as hardwood spent sulphite liquor. RESULTS The first and second round of delta-integrated transformants exhibited a trade-off between biomass and ethanol yield. Transformants showed increased inhibitor resistance phenotypes relative to parental controls specifically in fermentations with concentrated spent sulphite liquors at 40% and 80% v/v concentrations in 2% SC media. Unexpectedly, the xylose fermentation capacity of the transformants was reduced compared to the parental control, but certain combinations of genes had a minor impact (e.g. TAL1 + FDH1). The TAL1 + ICT1 combination negatively impacted on both biomass growth and ethanol yield, which could be linked to the ICT1 protein increasing transformant susceptibility to weak acids and temperature due to cell membrane changes. CONCLUSIONS The integration of the selected genes was proven to increase tolerance to pretreatment inhibitors in synthetic or industrial hydrolysates, but they were limited to the fermentation of glucose. However, some gene combination sequences had a reduced impact on xylose conversion.
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Affiliation(s)
- Bianca A Brandt
- Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Maria D P García-Aparicio
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Johann F Görgens
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Willem H van Zyl
- Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
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9
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Stress modulation as a means to improve yeasts for lignocellulose bioconversion. Appl Microbiol Biotechnol 2021; 105:4899-4918. [PMID: 34097119 DOI: 10.1007/s00253-021-11383-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/20/2021] [Accepted: 05/28/2021] [Indexed: 12/15/2022]
Abstract
The second-generation (2G) fermentation environment for lignocellulose conversion presents unique challenges to the fermentative organism that do not necessarily exist in other industrial fermentations. While extreme osmotic, heat, and nutrient starvation stresses are observed in sugar- and starch-based fermentation environments, additional pre-treatment-derived inhibitor stress, potentially exacerbated by stresses such as pH and product tolerance, exist in the 2G environment. Furthermore, in a consolidated bioprocessing (CBP) context, the organism is also challenged to secrete enzymes that may themselves lead to unfolded protein response and other stresses. This review will discuss responses of the yeast Saccharomyces cerevisiae to 2G-specific stresses and stress modulation strategies that can be followed to improve yeasts for this application. We also explore published -omics data and discuss relevant rational engineering, reverse engineering, and adaptation strategies, with the view of identifying genes or alleles that will make positive contributions to the overall robustness of 2G industrial strains. KEYPOINTS: • Stress tolerance is a key driver to successful application of yeast strains in biorefineries. • A wealth of data regarding stress responses has been gained through omics studies. • Integration of this knowledge could inform engineering of fit for purpose strains.
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10
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Li B, Xie CY, Yang BX, Gou M, Xia ZY, Sun ZY, Tang YQ. The response mechanisms of industrial Saccharomyces cerevisiae to acetic acid and formic acid during mixed glucose and xylose fermentation. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Ndukwe JK, Aliyu GO, Onwosi CO, Chukwu KO, Ezugworie FN. Mechanisms of weak acid-induced stress tolerance in yeasts: Prospects for improved bioethanol production from lignocellulosic biomass. Process Biochem 2020. [DOI: 10.1016/j.procbio.2019.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Inokuma K, Kurono H, den Haan R, van Zyl WH, Hasunuma T, Kondo A. Novel strategy for anchorage position control of GPI-attached proteins in the yeast cell wall using different GPI-anchoring domains. Metab Eng 2019; 57:110-117. [PMID: 31715252 DOI: 10.1016/j.ymben.2019.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/15/2019] [Accepted: 11/08/2019] [Indexed: 01/16/2023]
Abstract
The yeast cell surface provides space to display functional proteins. Heterologous proteins can be covalently anchored to the yeast cell wall by fusing them with the anchoring domain of glycosylphosphatidylinositol (GPI)-anchored cell wall proteins (GPI-CWPs). In the yeast cell-surface display system, the anchorage position of the target protein in the cell wall is an important factor that maximizes the capabilities of engineered yeast cells because the yeast cell wall consists of a 100- to 200-nm-thick microfibrillar array of glucan chains. However, knowledge is limited regarding the anchorage position of GPI-attached proteins in the yeast cell wall. Here, we report a comparative study on the effect of GPI-anchoring domain-heterologous protein fusions on yeast cell wall localization. GPI-anchoring domains derived from well-characterized GPI-CWPs, namely Sed1p and Sag1p, were used for the cell-surface display of heterologous proteins in the yeast Saccharomyces cerevisiae. Immunoelectron-microscopic analysis of enhanced green fluorescent protein (eGFP)-displaying cells revealed that the anchorage position of the GPI-attached protein in the cell wall could be controlled by changing the fused anchoring domain. eGFP fused with the Sed1-anchoring domain predominantly localized to the external surface of the cell wall, whereas the anchorage position of eGFP fused with the Sag1-anchoring domain was mainly inside the cell wall. We also demonstrate the application of the anchorage position control technique to improve the cellulolytic ability of cellulase-displaying yeast. The ethanol titer during the simultaneous saccharification and fermentation of hydrothermally-processed rice straw was improved by 30% after repositioning the exo- and endo-cellulases using Sed1- and Sag1-anchor domains. This novel anchorage position control strategy will enable the efficient utilization of the cell wall space in various fields of yeast cell-surface display technology.
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Affiliation(s)
- Kentaro Inokuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Hiroki Kurono
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Riaan den Haan
- Department of Biotechnology, University of the Western Cape, Bellville, 7530, South Africa
| | - Willem Heber van Zyl
- Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan; Engineering Biology Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.
| | - Akihiko Kondo
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan; Engineering Biology Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan; Biomass Engineering Program, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
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13
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Xu X, Bao M, Niu C, Wang J, Liu C, Zheng F, Li Y, Li Q. Engineering the cytosolic NADH availability in lager yeast to improve the aroma profile of beer. Biotechnol Lett 2019; 41:363-369. [PMID: 30707389 DOI: 10.1007/s10529-019-02653-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/25/2019] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To improve the aroma profile of beer by using metabolic engineering to increase the availability of cytosolic NADH in lager yeast. RESULTS To alter NADH levels in lager yeast, the native FDH1 (YOR388C) encoding NAD+-dependent formate dehydrogenase was overexpressed in the yeast strain M14, yielding strain M-FDH1. This led to a simultaneous increase of NADH availability and NADH/NAD+ ratio in the M-FDH1 strain during fermentation. At the end of the main fermentation period, ethanol production by strain M-FDH1 was decreased by 13.2%, while glycerol production was enhanced by 129.4%, compared to the parental strain respectively. The production of esters and fusel alcohols by strains M14 and M-FDH1 was similar. By contrast, strain M-FDH1 generally produced less organic acids and off-flavor components than strain M14, improving the beer aroma. CONCLUSIONS Increased NADH availability led to rerouting of the carbon flux toward NADH-consuming pathways and accelerated the NADH-dependent reducing reactions in yeast, greatly impacting the formation of aroma compounds and improving the beer aroma.
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Affiliation(s)
- Xin Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Min Bao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Chengtuo Niu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Jinjing Wang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Chunfeng Liu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Feiyun Zheng
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Yongxian Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Qi Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China.
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China.
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14
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Xie D. Integrating Cellular and Bioprocess Engineering in the Non-Conventional Yeast Yarrowia lipolytica for Biodiesel Production: A Review. Front Bioeng Biotechnol 2017; 5:65. [PMID: 29090211 PMCID: PMC5650997 DOI: 10.3389/fbioe.2017.00065] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/02/2017] [Indexed: 12/14/2022] Open
Abstract
As one of the major biofuels to replace fossil fuel, biodiesel has now attracted more and more attention due to its advantages in higher energy density and overall less greenhouse gas generation. Biodiesel (fatty acid alkyl esters) is produced by chemically or enzymatically catalyzed transesterification of lipids from microbial cells, microalgae, oil crops, or animal fats. Currently, plant oils or waste cooking oils/fats remain the major source for biodiesel production via enzymatic route, but the production capacity is limited either by the uncertain supplement of plant oils or by the low or inconsistent quality of waste oils/fats. In the past decades, significant progresses have been made on synthesis of microalgae oils directly from CO2via a photosynthesis process, but the production cost from any current technologies is still too high to be commercialized due to microalgae’s slow growth rate on CO2, inefficiency in photo-bioreactors, lack of efficient contamination control methods, and high cost in downstream recovery. At the same time, many oleaginous microorganisms have been studied to produce lipids via the fatty acid synthesis pathway under aerobic fermentation conditions, among them one of the most studied is the non-conventional yeast, Yarrowia lipolytica, which is able to produce fatty acids at very high titer, rate, and yield from various economical substrates. This review summarizes the recent research progresses in both cellular and bioprocess engineering in Y. lipolytica to produce lipids at a low cost that may lead to commercial-scale biodiesel production. Specific technologies include the strain engineering for using various substrates, metabolic engineering in high-yield lipid synthesis, cell morphology study for efficient substrate uptake and product formation, free fatty acid formation and secretion for improved downstream recovery, and fermentation engineering for higher productivities and less operating cost. To further improve the economics of the microbial oil-based biodiesel, production of lipid-related or -derived high-value products are also discussed.
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Affiliation(s)
- Dongming Xie
- Massachusetts Biomanufacturing Center, Department of Chemical Engineering, University of Massachusetts Lowell, Lowell, MA, United States
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15
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Nambu-Nishida Y, Sakihama Y, Ishii J, Hasunuma T, Kondo A. Selection of yeast Saccharomyces cerevisiae promoters available for xylose cultivation and fermentation. J Biosci Bioeng 2017; 125:76-86. [PMID: 28869192 DOI: 10.1016/j.jbiosc.2017.08.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/21/2017] [Accepted: 08/02/2017] [Indexed: 11/26/2022]
Abstract
To efficiently utilize xylose, a major sugar component of hemicelluloses, in Saccharomyces cerevisiae requires the proper expression of varied exogenous and endogenous genes. To expand the repertoire of promoters in engineered xylose-utilizing yeast strains, we selected promoters in S. cerevisiae during cultivation and fermentation using xylose as a carbon source. To select candidate promoters that function in the presence of xylose, we performed comprehensive gene expression analyses using xylose-utilizing yeast strains both during xylose and glucose fermentation. Based on microarray data, we chose 29 genes that showed strong, moderate, and weak expression in xylose rather than glucose fermentation. The activities of these promoters in a xylose-utilizing yeast strain were measured by lacZ reporter gene assays over time during aerobic cultivation and microaerobic fermentation, both in xylose and glucose media. In xylose media, PTDH3, PFBA1, and PTDH1 were favorable for high expression, and PSED1, PHXT7, PPDC1, PTEF1, PTPI1, and PPGK1 were acceptable for medium-high expression in aerobic cultivation, and moderate expression in microaerobic fermentation. PTEF2 allowed moderate expression in aerobic culture and weak expression in microaerobic fermentation, although it showed medium-high expression in glucose media. PZWF1 and PSOL4 allowed moderate expression in aerobic cultivation, while showing weak but clear expression in microaerobic fermentation. PALD3 and PTKL2 showed moderate promoter activity in aerobic cultivation, but showed almost no activity in microaerobic fermentation. The knowledge of promoter activities in xylose cultivation obtained in this study will permit the control of gene expression in engineered xylose-utilizing yeast strains that are used for hemicellulose fermentation.
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Affiliation(s)
- Yumiko Nambu-Nishida
- Technology Research Association of Highly Efficient Gene Design (TRAHED), 7-1-49 Minatojimaminamimachi, Chuo-ku, Kobe 650-0047, Japan; Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Yuri Sakihama
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Jun Ishii
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Akihiko Kondo
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan; Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan; Biomass Engineering Program, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
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16
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Henriques SF, Mira NP, Sá-Correia I. Genome-wide search for candidate genes for yeast robustness improvement against formic acid reveals novel susceptibility (Trk1 and positive regulators) and resistance (Haa1-regulon) determinants. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:96. [PMID: 28428821 PMCID: PMC5395885 DOI: 10.1186/s13068-017-0781-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 04/11/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Formic acid is an inhibitory compound present in lignocellulosic hydrolysates. Understanding the complex molecular mechanisms underlying Saccharomyces cerevisiae tolerance to this weak acid at the system level is instrumental to guide synthetic pathway engineering for robustness improvement of industrial strains envisaging their use in lignocellulosic biorefineries. RESULTS This study was performed to identify, at a genome-wide scale, genes whose expression confers protection or susceptibility to formic acid, based on the screening of a haploid deletion mutant collection to search for these phenotypes in the presence of 60, 70 and 80 mM of this acid, at pH 4.5. This chemogenomic analysis allowed the identification of 172 determinants of tolerance and 41 determinants of susceptibility to formic acid. Clustering of genes required for maximal tolerance to this weak acid, based on their biological function, indicates an enrichment of those involved in intracellular trafficking and protein synthesis, cell wall and cytoskeleton organization, carbohydrate metabolism, lipid, amino acid and vitamin metabolism, response to stress, chromatin remodelling, transcription and internal pH homeostasis. Among these genes is HAA1 encoding the main transcriptional regulator of yeast transcriptome reprograming in response to acetic acid and genes of the Haa1-regulon; all demonstrated determinants of acetic acid tolerance. Among the genes that when deleted lead to increased tolerance to formic acid, TRK1, encoding the high-affinity potassium transporter and a determinant of resistance to acetic acid, was surprisingly found. Consistently, genes encoding positive regulators of Trk1 activity were also identified as formic acid susceptibility determinants, while a negative regulator confers protection. At a saturating K+ concentration of 20 mM, the deletion mutant trk1Δ was found to exhibit a much higher tolerance compared with the parental strain. Given that trk1Δ accumulates lower levels of radiolabelled formic acid, compared to the parental strain, it is hypothesized that Trk1 facilitates formic acid uptake into the yeast cell. CONCLUSIONS The list of genes resulting from this study shows a few marked differences from the list of genes conferring protection to acetic acid and provides potentially valuable information to guide improvement programmes for the development of more robust strains against formic acid.
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Affiliation(s)
- Sílvia F. Henriques
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
| | - Nuno P. Mira
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
| | - Isabel Sá-Correia
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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17
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Hasunuma T, Kondo A. Production of Fuels and Chemicals from Biomass by Integrated Bioprocesses. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1002/9783527807833.ch5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Tomohisa Hasunuma
- Kobe University; Graduate School of Science, Technology and Innovation; 1-1 Rokkodai Nada Kobe 657-8501 Japan
| | - Akihiko Kondo
- RIKEN; Biomass Engineering Program; 1-7-22 Suehiro-cho, Tsurumi Yokohama 230-0045 Japan
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18
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Genetic Enhancement of Saccharomyces cerevisiae for First and Second Generation Ethanol Production. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1201/b19347-11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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19
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Thompson OA, Hawkins GM, Gorsich SW, Doran-Peterson J. Phenotypic characterization and comparative transcriptomics of evolved Saccharomyces cerevisiae strains with improved tolerance to lignocellulosic derived inhibitors. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:200. [PMID: 27679668 PMCID: PMC5029107 DOI: 10.1186/s13068-016-0614-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/07/2016] [Indexed: 05/15/2023]
Abstract
BACKGROUND Lignocellulosic biomass continues to be investigated as a viable source for bioethanol production. However, the pretreatment process generates inhibitory compounds that impair the growth and fermentation performance of microorganisms such as Saccharomyces cerevisiae. Pinewood specifically has been shown to be challenging in obtaining industrially relevant ethanol titers. An industrial S. cerevisiae strain was subjected to directed evolution and adaptation in pretreated pine biomass and resultant strains, GHP1 and GHP4, exhibited improved growth and fermentative ability on pretreated pine in the presence of related inhibitory compounds. A comparative transcriptomic approach was applied to identify and characterize differences in phenotypic stability of evolved strains. RESULTS Evolved strains displayed different fermentative capabilities with pretreated pine that appear to be influenced by the addition or absence of 13 inhibitory compounds during pre-culturing. GHP4 performance was consistent independent of culturing conditions, while GHP1 performance was dependent on culturing with inhibitors. Comparative transcriptomics revealed 52 genes potentially associated with stress responses to multiple inhibitors simultaneously. Fluorescence microscopy revealed improved cellular integrity of both strains with mitochondria exhibiting resistance to the damaging effects of inhibitors in contrast to the parent. CONCLUSIONS Multiple potentially novel genetic targets have been discovered for understanding stress tolerance through the characterization of our evolved strains. This study specifically examines the synergistic effects of multiple inhibitors and identified targets will guide future studies in remediating effects of inhibitors and further development of robust yeast strains for multiple industrial applications.
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Affiliation(s)
| | - Gary M. Hawkins
- Department of Microbiology, University of Georgia, Athens, GA 30602 USA
| | - Steven W. Gorsich
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859 USA
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20
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Hasunuma T, Sakamoto T, Kondo A. Inverse metabolic engineering based on transient acclimation of yeast improves acid-containing xylose fermentation and tolerance to formic and acetic acids. Appl Microbiol Biotechnol 2016; 100:1027-38. [PMID: 26521247 DOI: 10.1007/s00253-015-7094-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 09/28/2015] [Accepted: 10/11/2015] [Indexed: 02/02/2023]
Abstract
Improving the production of ethanol from xylose is an important goal in metabolic engineering of Saccharomyces cerevisiae. Furthermore, S. cerevisiae must produce ethanol in the presence of weak acids (formate and acetate) generated during pre-treatment of lignocellulosic biomass. In this study, weak acid-containing xylose fermentation was significantly improved using cells that were acclimated to the weak acids during pre-cultivation. Transcriptome analyses showed that levels of transcripts for transcriptional/translational machinery-related genes (RTC3 and ANB1) were enhanced by formate and acetate acclimation. Recombinant yeast strains overexpressing RTC3 and ANB1 demonstrated improved ethanol production from xylose in the presence of the weak acids, along with improved tolerance to the acids. Novel metabolic engineering strategy based on the combination of short-term acclimation and system-wide analysis was developed, which can develop stress-tolerant strains in a short period of time, although conventional evolutionary engineering approach has required long periods of time to isolate inhibitor-adapted strains.
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Affiliation(s)
- Tomohisa Hasunuma
- Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Takatoshi Sakamoto
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Akihiko Kondo
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan.
- Biomass Engineering Program, RIKEN, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan.
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21
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Ninomiya K, Ogino C, Ishizaki M, Yasuda M, Shimizu N, Takahashi K. Effect of post-pretreatment washing on saccharification and co-fermentation from bagasse pretreated with biocompatible cholinium ionic liquid. Biochem Eng J 2015. [DOI: 10.1016/j.bej.2015.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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22
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Oshoma CE, Greetham D, Louis EJ, Smart KA, Phister TG, Powell C, Du C. Screening of Non- Saccharomyces cerevisiae Strains for Tolerance to Formic Acid in Bioethanol Fermentation. PLoS One 2015; 10:e0135626. [PMID: 26284784 PMCID: PMC4540574 DOI: 10.1371/journal.pone.0135626] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 07/24/2015] [Indexed: 11/18/2022] Open
Abstract
Formic acid is one of the major inhibitory compounds present in hydrolysates derived from lignocellulosic materials, the presence of which can significantly hamper the efficiency of converting available sugars into bioethanol. This study investigated the potential for screening formic acid tolerance in non-Saccharomyces cerevisiae yeast strains, which could be used for the development of advanced generation bioethanol processes. Spot plate and phenotypic microarray methods were used to screen the formic acid tolerance of 7 non-Saccharomyces cerevisiae yeasts. S. kudriavzeii IFO1802 and S. arboricolus 2.3319 displayed a higher formic acid tolerance when compared to other strains in the study. Strain S. arboricolus 2.3319 was selected for further investigation due to its genetic variability among the Saccharomyces species as related to Saccharomyces cerevisiae and availability of two sibling strains: S. arboricolus 2.3317 and 2.3318 in the lab. The tolerance of S. arboricolus strains (2.3317, 2.3318 and 2.3319) to formic acid was further investigated by lab-scale fermentation analysis, and compared with S. cerevisiae NCYC2592. S. arboricolus 2.3319 demonstrated improved formic acid tolerance and a similar bioethanol synthesis capacity to S. cerevisiae NCYC2592, while S. arboricolus 2.3317 and 2.3318 exhibited an overall inferior performance. Metabolite analysis indicated that S. arboricolus strain 2.3319 accumulated comparatively high concentrations of glycerol and glycogen, which may have contributed to its ability to tolerate high levels of formic acid.
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Affiliation(s)
- Cyprian E. Oshoma
- Bioenergy and Brewing Science Building, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leics, United Kingdom
| | - Darren Greetham
- Bioenergy and Brewing Science Building, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leics, United Kingdom
| | - Edward J. Louis
- Centre for Genetic Architecture of Complex Traits, University of Leicester, Leicester, United Kingdom
| | | | - Trevor G. Phister
- PepsiCo Int. Beaumont Park, Leycroft Road, Leicester, United Kingdom
| | - Chris Powell
- Bioenergy and Brewing Science Building, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leics, United Kingdom
| | - Chenyu Du
- Bioenergy and Brewing Science Building, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leics, United Kingdom
- School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield, United Kingdom
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Sànchez Nogué V, Karhumaa K. Xylose fermentation as a challenge for commercialization of lignocellulosic fuels and chemicals. Biotechnol Lett 2014; 37:761-72. [DOI: 10.1007/s10529-014-1756-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 12/11/2014] [Indexed: 10/24/2022]
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24
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Efficient co-displaying and artificial ratio control of α-amylase and glucoamylase on the yeast cell surface by using combinations of different anchoring domains. Appl Microbiol Biotechnol 2014; 99:1655-63. [PMID: 25432675 DOI: 10.1007/s00253-014-6250-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/16/2014] [Accepted: 11/18/2014] [Indexed: 10/24/2022]
Abstract
Recombinant yeast strains that display heterologous amylolytic enzymes on their cell surface via the glycosylphosphatidylinositol (GPI)-anchoring system are considered as promising biocatalysts for direct ethanol production from starchy materials. For the effective hydrolysis of these materials, the ratio optimization of multienzyme activity displayed on the cell surface is important. In this study, we have presented a ratio control system of multienzymes displayed on the yeast cell surface by using different GPI-anchoring domains. The novel gene cassettes for the cell-surface display of Streptococcus bovis α-amylase and Rhizopus oryzae glucoamylase were constructed using the Saccharomyces cerevisiae SED1 promoter and two different GPI-anchoring regions derived from Saccharomyces cerevisiae SED1 or SAG1. These gene cassettes were integrated into the Saccharomyces cerevisiae genome in different combinations. Then, the cell-surface α-amylase and glucoamylase activities and ethanol productivity of these recombinant strains were evaluated. The combinations of the gene cassettes of these enzymes affected the ratio of cell-surface α-amylase and glucoamylase activities and ethanol productivity of the recombinant strains. The highest ethanol productivity from raw starch was achieved by the strain harboring one α-amylase gene cassette carrying the SED1-anchoring region and two glucoamylase gene cassettes carrying the SED1-anchoring region (BY-AASS/GASS/GASS). This strain yielded 22.5 ± 0.6 g/L of ethanol from 100 g/L of raw starch in 120 h of fermentation.
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25
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Hasunuma T, Hori Y, Sakamoto T, Ochiai M, Hatanaka H, Kondo A. Development of a GIN11/FRT-based multiple-gene integration technique affording inhibitor-tolerant, hemicellulolytic, xylose-utilizing abilities to industrial Saccharomyces cerevisiae strains for ethanol production from undetoxified lignocellulosic hemicelluloses. Microb Cell Fact 2014; 13:145. [PMID: 25306430 PMCID: PMC4198627 DOI: 10.1186/s12934-014-0145-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 10/03/2014] [Indexed: 11/30/2022] Open
Abstract
Background Bioethanol produced by the yeast Saccharomyces cerevisiae is currently one of the most promising alternatives to conventional transport fuels. Lignocellulosic hemicelluloses obtained after hydrothermal pretreatment are important feedstock for bioethanol production. However, hemicellulosic materials cannot be directly fermented by yeast: xylan backbone of hemicelluloses must first be hydrolyzed by heterologous hemicellulases to release xylose, and the yeast must then ferment xylose in the presence of fermentation inhibitors generated during the pretreatment. Results A GIN11/FRT-based multiple-gene integration system was developed for introducing multiple functions into the recombinant S. cerevisiae strains engineered with the xylose metabolic pathway. Antibiotic markers were efficiently recycled by a novel counter selection strategy using galactose-induced expression of both FLP recombinase gene and GIN11 flanked by FLP recombinase recognition target (FRT) sequences. Nine genes were functionally expressed in an industrial diploid strain of S. cerevisiae: endoxylanase gene from Trichoderma reesei, xylosidase gene from Aspergillus oryzae, β-glucosidase gene from Aspergillus aculeatus, xylose reductase and xylitol dehydrogenase genes from Scheffersomyces stipitis, and XKS1, TAL1, FDH1 and ADH1 variant from S. cerevisiae. The genes were introduced using the homozygous integration system and afforded hemicellulolytic, xylose-assimilating and inhibitor-tolerant abilities to the strain. The engineered yeast strain demonstrated 2.7-fold higher ethanol titer from hemicellulosic material than a xylose-assimilating yeast strain. Furthermore, hemicellulolytic enzymes displayed on the yeast cell surface hydrolyzed hemicelluloses that were not hydrolyzed by a commercial enzyme, leading to increased sugar utilization for improved ethanol production. Conclusions The multifunctional yeast strain, developed using a GIN11/FRT-based marker recycling system, achieved direct conversion of hemicellulosic biomass to ethanol without the addition of exogenous hemicellulolytic enzymes. No detoxification processes were required. The multiple-gene integration technique is a powerful approach for introducing and improving the biomass fermentation ability of industrial diploid S. cerevisiae strains. Electronic supplementary material The online version of this article (doi:10.1186/s12934-014-0145-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tomohisa Hasunuma
- Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan.
| | - Yoshimi Hori
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan.
| | - Takatoshi Sakamoto
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan.
| | - Misa Ochiai
- Suntory Research Center, 1-1-1 Wakayamadai, Shimamoto-cho, Osaka, Mishima-gun, 618-8503, Japan.
| | - Haruyo Hatanaka
- Suntory Research Center, 1-1-1 Wakayamadai, Shimamoto-cho, Osaka, Mishima-gun, 618-8503, Japan.
| | - Akihiko Kondo
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan. .,Biomass Engineering Program, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
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26
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Zhou H, Lan T, Dien BS, Hector RE, Zhu JY. Comparisons of fiveSaccharomyces cerevisiaestrains for ethanol production from SPORL-pretreated lodgepole pine. Biotechnol Prog 2014; 30:1076-83. [DOI: 10.1002/btpr.1937] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 05/08/2014] [Indexed: 12/30/2022]
Affiliation(s)
- Haifeng Zhou
- School of Chemistry Chemical Eng.; South China University Technol.; Guangzhou China
- USDA Forest Service, Forest Products Laboratory; Madison WI
| | - Tianqing Lan
- School of Light Industry and Food Sciences; Kunming Polytechnic University; Kunming China
- USDA Forest Service, Forest Products Laboratory; Madison WI
| | - Bruce S. Dien
- USDA Agricultural Research Service; National Center for Agricultural Utilization Research; Peoria IL
| | - Ronald E. Hector
- USDA Agricultural Research Service; National Center for Agricultural Utilization Research; Peoria IL
| | - J. Y. Zhu
- USDA Forest Service, Forest Products Laboratory; Madison WI
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27
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Kricka W, Fitzpatrick J, Bond U. Metabolic engineering of yeasts by heterologous enzyme production for degradation of cellulose and hemicellulose from biomass: a perspective. Front Microbiol 2014; 5:174. [PMID: 24795706 PMCID: PMC4001029 DOI: 10.3389/fmicb.2014.00174] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/31/2014] [Indexed: 11/13/2022] Open
Abstract
This review focuses on current approaches to metabolic engineering of ethanologenic yeast species for the production of bioethanol from complex lignocellulose biomass sources. The experimental strategies for the degradation of the cellulose and xylose-components of lignocellulose are reviewed. Limitations to the current approaches are discussed and novel solutions proposed.
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Affiliation(s)
- William Kricka
- School of Genetics and Microbiology, Department of Microbiology, Trinity College Dublin Dublin, Ireland
| | - James Fitzpatrick
- School of Genetics and Microbiology, Department of Microbiology, Trinity College Dublin Dublin, Ireland
| | - Ursula Bond
- School of Genetics and Microbiology, Department of Microbiology, Trinity College Dublin Dublin, Ireland
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Hasunuma T, Ismail KSK, Nambu Y, Kondo A. Co-expression of TAL1 and ADH1 in recombinant xylose-fermenting Saccharomyces cerevisiae improves ethanol production from lignocellulosic hydrolysates in the presence of furfural. J Biosci Bioeng 2014; 117:165-169. [DOI: 10.1016/j.jbiosc.2013.07.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 07/03/2013] [Accepted: 07/15/2013] [Indexed: 10/26/2022]
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Inokuma K, Hasunuma T, Kondo A. Efficient yeast cell-surface display of exo- and endo-cellulase using the SED1 anchoring region and its original promoter. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:8. [PMID: 24423072 PMCID: PMC3900695 DOI: 10.1186/1754-6834-7-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 12/24/2013] [Indexed: 05/10/2023]
Abstract
BACKGROUND The recombinant yeast strains displaying the heterologous cellulolytic enzymes on the cell surface using the glycosylphosphatidylinositol (GPI) anchoring system are considered promising biocatalysts for direct conversion of lignocellulosic materials to ethanol. However, the cellulolytic activities of the conventional cellulase-displaying yeast strains are insufficient for the hydrolysis of cellulose. In this study, we constructed novel gene cassettes for the efficient cellulose utilization by cellulase-displaying yeast strains. RESULTS The novel gene cassettes for the cell-surface display of Aspergillus aculeatus β-glucosidase (BGL1) and Trichoderma reeseii endoglucanase II (EGII) were constructed using the promoter and the GPI anchoring region derived from Saccharomyces cerevisiae SED1. The gene cassettes were integrated into the S. cerevisiae genome, then the β-glucosidase activity of these recombinant strains was evaluated. We revealed that simultaneous utilization of the SED1 promoter and Sed1 anchoring domain in a gene cassette enabled highly-efficient enzyme integration into the cell wall. The β-glucosidase activity of recombinant yeast cells transduced with the novel gene cassette was 8.4-fold higher than that of a conventional strain. The novel EGII-displaying strain also achieved 106-fold higher hydrolysis activity against the water-insoluble cellulose than a conventional strain. Furthermore, direct ethanol production from hydrothermally processed rice straw was improved by the display of T. reeseii EGII using the novel gene cassette. CONCLUSIONS We have developed novel gene cassettes for the efficient cell-surface display of exo- and endo-type cellulolytic enzymes. The results suggest that this gene cassette has the wide applicability for cell-surface display and that cellulase-displaying yeasts have significant potential for cost-effective bioethanol production from lignocellulosic biomass.
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Affiliation(s)
- Kentaro Inokuma
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Tomohisa Hasunuma
- Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Akihiko Kondo
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
- Biomass Engineering Program, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- Department of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea
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Diao L, Liu Y, Qian F, Yang J, Jiang Y, Yang S. Construction of fast xylose-fermenting yeast based on industrial ethanol-producing diploid Saccharomyces cerevisiae by rational design and adaptive evolution. BMC Biotechnol 2013; 13:110. [PMID: 24354503 PMCID: PMC3878346 DOI: 10.1186/1472-6750-13-110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 12/10/2013] [Indexed: 12/22/2022] Open
Abstract
Background It remains a challenge for recombinant S. cerevisiae to convert xylose in lignocellulosic biomass hydrolysates to ethanol. Although industrial diploid strains are more robust compared to laboratory haploid strains, however, industrial diploid S. cerevisiae strains have been less pursued in previous studies. This work aims to construct fast xylose-fermenting yeast using an industrial ethanol-producing diploid S. cerevisiae strain as a host. Results Fast xylose-fermenting yeast was constructed by genome integration of xylose-utilizing genes and adaptive evolution, including 1) Piromyces XYLA was introduced to enable the host strain to convert xylose to xylulose; 2) endogenous genes (XKS1, RKI1, RPE1, TKL1, and TAL1) were overexpressed to accelerate conversion of xylulose to ethanol; 3) Candida intermedia GXF1, which encodes a xylose transporter, was introduced at the GRE3 locus to improve xylose uptake; 4) aerobic evolution in rich xylose media was carried out to increase growth and xylose consumption rates. The best evolved strain CIBTS0735 consumed 80 g/l glucose and 40 g/l xylose in rich media within 24 hours at an initial OD600 of 1.0 (0.63 g DCW/l) and produced 53 g/l ethanol. Conclusions Based on the above fermentation performance, we conclude that CIBTS0735 shows great potential for ethanol production from lignocellulosic biomass.
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Affiliation(s)
| | | | | | | | | | - Sheng Yang
- CAS Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
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Harnessing genetic diversity in Saccharomyces cerevisiae for fermentation of xylose in hydrolysates of alkaline hydrogen peroxide-pretreated biomass. Appl Environ Microbiol 2013; 80:540-54. [PMID: 24212571 DOI: 10.1128/aem.01885-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The fermentation of lignocellulose-derived sugars, particularly xylose, into ethanol by the yeast Saccharomyces cerevisiae is known to be inhibited by compounds produced during feedstock pretreatment. We devised a strategy that combined chemical profiling of pretreated feedstocks, high-throughput phenotyping of genetically diverse S. cerevisiae strains isolated from a range of ecological niches, and directed engineering and evolution against identified inhibitors to produce strains with improved fermentation properties. We identified and quantified for the first time the major inhibitory compounds in alkaline hydrogen peroxide (AHP)-pretreated lignocellulosic hydrolysates, including Na(+), acetate, and p-coumaric (pCA) and ferulic (FA) acids. By phenotyping these yeast strains for their abilities to grow in the presence of these AHP inhibitors, one heterozygous diploid strain tolerant to all four inhibitors was selected, engineered for xylose metabolism, and then allowed to evolve on xylose with increasing amounts of pCA and FA. After only 149 generations, one evolved isolate, GLBRCY87, exhibited faster xylose uptake rates in both laboratory media and AHP switchgrass hydrolysate than its ancestral GLBRCY73 strain and completely converted 115 g/liter of total sugars in undetoxified AHP hydrolysate into more than 40 g/liter ethanol. Strikingly, genome sequencing revealed that during the evolution from GLBRCY73, the GLBRCY87 strain acquired the conversion of heterozygous to homozygous alleles in chromosome VII and amplification of chromosome XIV. Our approach highlights that simultaneous selection on xylose and pCA or FA with a wild S. cerevisiae strain containing inherent tolerance to AHP pretreatment inhibitors has potential for rapid evolution of robust properties in lignocellulosic biofuel production.
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32
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Matano Y, Hasunuma T, Kondo A. Cell recycle batch fermentation of high-solid lignocellulose using a recombinant cellulase-displaying yeast strain for high yield ethanol production in consolidated bioprocessing. BIORESOURCE TECHNOLOGY 2013; 135:403-9. [PMID: 22954707 DOI: 10.1016/j.biortech.2012.07.025] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 07/02/2012] [Accepted: 07/05/2012] [Indexed: 05/26/2023]
Abstract
The aim of this study is to develop a scheme of cell recycle batch fermentation (CRBF) of high-solid lignocellulosic materials. Two-phase separation consisting of rough removal of lignocellulosic residues by low-speed centrifugation and solid-liquid separation enabled effective collection of Saccharomyces cerevisiae cells with decreased lignin and ash. Five consecutive batch fermentation of 200 g/L rice straw hydrothermally pretreated led to an average ethanol titer of 34.5 g/L. Moreover, the display of cellulases on the recombinant yeast cell surface increased ethanol titer to 42.2 g/L. After, five-cycle fermentation, only 3.3 g/L sugar was retained in the fermentation medium, because cellulase displayed on the cell surface hydrolyzed cellulose that was not hydrolyzed by commercial cellulases or free secreted cellulases. Fermentation ability of the recombinant strain was successfully kept during a five-cycle repeated batch fermentation with 86.3% of theoretical yield based on starting biomass.
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Affiliation(s)
- Yuki Matano
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
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Kim OC, Suwannarangsee S, Oh DB, Kim S, Seo JW, Kim CH, Kang HA, Kim JY, Kwon O. Transcriptome analysis of xylose metabolism in the thermotolerant methylotrophic yeast Hansenula polymorpha. Bioprocess Biosyst Eng 2013; 36:1509-18. [PMID: 23380941 DOI: 10.1007/s00449-013-0909-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 01/21/2013] [Indexed: 11/29/2022]
Abstract
The thermotolerant methylotrophic yeast Hansenula polymorpha is able to grow at elevated temperature up to 48 °C as one of a few yeast strains which are naturally capable of alcoholic fermentation of xylose, a pentose sugar abundant in lignocellulosic biomass. However, the current level of ethanol production from xylose by H. polymorpha is still very low compared to those of other xylose-fermenting strains. Therefore, it is necessary to analyze and remodel the xylose metabolism in H. polymorpha at the whole genome level to identify and overcome these limits. In the present study, the transcriptomes of H. polymorpha grown on xylose were compared with those of glucose-grown cells under both aerobic and microaerobic conditions. Approximately, two percent of H. polymorpha genes were either up- or down-regulated by more than two-fold during the growth on xylose. The majority of the up-regulated genes were involved in metabolism. Some genes involved in xylose metabolism, such as XYL1, XYL2, and TAL1 were also up-regulated, despite the fact that the differences in their induction level were only about three-fold. On the other hand, the majority of the down-regulated genes were involved in metabolism and cellular transport. Interestingly, some genes involved in glycolysis and ethanol fermentation were also repressed during growth on xylose, suggesting that these genes are good targets for engineering H. polymorpha to improve xylose fermentation.
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Affiliation(s)
- Oh Cheol Kim
- Systems and Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 305-806, Korea
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Jönsson LJ, Alriksson B, Nilvebrant NO. Bioconversion of lignocellulose: inhibitors and detoxification. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:16. [PMID: 23356676 PMCID: PMC3574029 DOI: 10.1186/1754-6834-6-16] [Citation(s) in RCA: 611] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 01/16/2013] [Indexed: 05/17/2023]
Abstract
Bioconversion of lignocellulose by microbial fermentation is typically preceded by an acidic thermochemical pretreatment step designed to facilitate enzymatic hydrolysis of cellulose. Substances formed during the pretreatment of the lignocellulosic feedstock inhibit enzymatic hydrolysis as well as microbial fermentation steps. This review focuses on inhibitors from lignocellulosic feedstocks and how conditioning of slurries and hydrolysates can be used to alleviate inhibition problems. Novel developments in the area include chemical in-situ detoxification by using reducing agents, and methods that improve the performance of both enzymatic and microbial biocatalysts.
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Affiliation(s)
- Leif J Jönsson
- Department of Chemistry, Umeå University, Umeå SE-901 87, Sweden
| | - Björn Alriksson
- Processum Biorefinery Initiative AB, Örnsköldsvik, SE-891 22, Sweden
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35
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Kondo A, Ishii J, Hara KY, Hasunuma T, Matsuda F. Development of microbial cell factories for bio-refinery through synthetic bioengineering. J Biotechnol 2013; 163:204-16. [DOI: 10.1016/j.jbiotec.2012.05.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 05/10/2012] [Accepted: 05/18/2012] [Indexed: 12/24/2022]
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36
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Gene expression cross-profiling in genetically modified industrial Saccharomyces cerevisiae strains during high-temperature ethanol production from xylose. J Biotechnol 2013; 163:50-60. [DOI: 10.1016/j.jbiotec.2012.10.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 10/24/2012] [Accepted: 10/26/2012] [Indexed: 11/22/2022]
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37
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Matano Y, Hasunuma T, Kondo A. Simultaneous improvement of saccharification and ethanol production from crystalline cellulose by alleviation of irreversible adsorption of cellulase with a cell surface-engineered yeast strain. Appl Microbiol Biotechnol 2012. [DOI: 10.1007/s00253-012-4587-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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38
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Aeling KA, Salmon KA, Laplaza JM, Li L, Headman JR, Hutagalung AH, Picataggio S. Co-fermentation of xylose and cellobiose by an engineered Saccharomyces cerevisiae. ACTA ACUST UNITED AC 2012; 39:1597-604. [DOI: 10.1007/s10295-012-1169-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 07/10/2012] [Indexed: 11/28/2022]
Abstract
Abstract
We have integrated and coordinately expressed in Saccharomyces cerevisiae a xylose isomerase and cellobiose phosphorylase from Ruminococcus flavefaciens that enables fermentation of glucose, xylose, and cellobiose under completely anaerobic conditions. The native xylose isomerase was active in cell-free extracts from yeast transformants containing a single integrated copy of the gene. We improved the activity of the enzyme and its affinity for xylose by modifications to the 5′-end of the gene, site-directed mutagenesis, and codon optimization. The improved enzyme, designated RfCO*, demonstrated a 4.8-fold increase in activity compared to the native xylose isomerase, with a Km for xylose of 66.7 mM and a specific activity of 1.41 μmol/min/mg. In comparison, the native xylose isomerase was found to have a Km for xylose of 117.1 mM and a specific activity of 0.29 μmol/min/mg. The coordinate over-expression of RfCO* along with cellobiose phosphorylase, cellobiose transporters, the endogenous genes GAL2 and XKS1, and disruption of the native PHO13 and GRE3 genes allowed the fermentation of glucose, xylose, and cellobiose under completely anaerobic conditions. Interestingly, this strain was unable to utilize xylose or cellobiose as a sole carbon source for growth under anaerobic conditions, thus minimizing yield loss to biomass formation and maximizing ethanol yield during their fermentation.
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Affiliation(s)
| | | | - José M Laplaza
- grid.439009.7 Verdezyne 2715 Loker Ave W. 92010 Carlsbad CA USA
| | - Ling Li
- BP Biofuels 4955 Directors Place 92121 San Diego CA USA
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39
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Ishii J, Yoshimura K, Hasunuma T, Kondo A. Reduction of furan derivatives by overexpressing NADH-dependent Adh1 improves ethanol fermentation using xylose as sole carbon source with Saccharomyces cerevisiae harboring XR–XDH pathway. Appl Microbiol Biotechnol 2012; 97:2597-607. [DOI: 10.1007/s00253-012-4376-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 08/13/2012] [Accepted: 08/14/2012] [Indexed: 10/27/2022]
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40
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Consolidated bioprocessing and simultaneous saccharification and fermentation of lignocellulose to ethanol with thermotolerant yeast strains. Process Biochem 2012. [DOI: 10.1016/j.procbio.2012.05.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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41
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Implementation of a transhydrogenase-like shunt to counter redox imbalance during xylose fermentation in Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2012; 97:1669-78. [PMID: 22851014 DOI: 10.1007/s00253-012-4298-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 07/10/2012] [Accepted: 07/11/2012] [Indexed: 01/10/2023]
Abstract
Three enzymes responsible for the transhydrogenase-like shunt, including malic enzyme (encoded by MAE1), malate dehydrogenase (MDH2), and pyruvate carboxylase (PYC2), were overexpressed to regulate the redox state in xylose-fermenting recombinant Saccharomyces cerevisiae. The YPH499XU/MAE1 strain was constructed by overexpressing native Mae1p in the YPH499XU strain expressing xylose reductase and xylitol dehydrogenase from Scheffersomyces stipitis, and native xylulokinase. Analysis of the xylose fermentation profile under semi-anaerobic conditions revealed that the ethanol yield in the YPH499XU/MAE1 strain (0.38 ± 0.01 g g⁻¹ xylose consumed) was improved from that of the control strain (0.31 ± 0.01 g g⁻¹ xylose consumed). Reduced xylitol production was also observed in YPH499XU/MAE1, suggesting that the redox balance was altered by Mae1p overexpression. Analysis of intracellular metabolites showed that the redox imbalance during xylose fermentation was partly relieved in the transformant. The specific ethanol production rate in the YPH499XU/MAE1-MDH2 strain was 1.25-fold higher than that of YPH499XU/MAE1 due to the additional overexpression of Mdh2p, whereas the ethanol yield was identical to that of YPH499XU/MAE1. The specific xylose consumption rate was drastically increased in the YPH499XU/MAE1-MDH2-PYC2 strain. However, poor ethanol yield as well as increased production of xylitol was observed. These results demonstrate that the transhydrogenase function implemented in S. cerevisiae can regulate the redox state of yeast cells.
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Fujitomi K, Sanda T, Hasunuma T, Kondo A. Deletion of the PHO13 gene in Saccharomyces cerevisiae improves ethanol production from lignocellulosic hydrolysate in the presence of acetic and formic acids, and furfural. BIORESOURCE TECHNOLOGY 2012; 111:161-166. [PMID: 22357292 DOI: 10.1016/j.biortech.2012.01.161] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 01/28/2012] [Accepted: 01/29/2012] [Indexed: 05/28/2023]
Abstract
For efficient bioethanol production from lignocellulosic biomass by Saccharomyces cerevisiae, it is necessary to improve cellular tolerance to toxic compounds released during the pretreatment of biomass. The gene encoding p-nitrophenylphosphatase, PHO13, was disrupted in a recombinant xylose-fermenting S. cerevisiae strain, which improved ethanol production from xylose in the presence of three major inhibitors, acetic and formic acids, and furfural. In medium supplemented with 30 mM acetic acid, the ethanol yield obtained by the ΔPHO13 mutant was 0.45 g-ethanol/g-xylose. Notably, the specific ethanol productivity of the mutant in the presence of 90 mM furfural was fourfold higher than that of the control strain. The PHO13-disrupted strain produced ethanol from rice straw hydrolysate obtained by liquid hot-water pretreatment with a greater than fourfold higher xylose consumption rate than the control. Together, our findings demonstrate that PHO13 deletion is a simple, but effective, approach for improving cellulosic bioethanol production by S. cerevisiae.
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Affiliation(s)
- Keisuke Fujitomi
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
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Matano Y, Hasunuma T, Kondo A. Display of cellulases on the cell surface of Saccharomyces cerevisiae for high yield ethanol production from high-solid lignocellulosic biomass. BIORESOURCE TECHNOLOGY 2012; 108:128-33. [PMID: 22265982 DOI: 10.1016/j.biortech.2011.12.144] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 12/28/2011] [Accepted: 12/30/2011] [Indexed: 05/04/2023]
Abstract
Economically feasible processes for industrial cellulosic ethanol production requires increasing the final ethanol titer during fermentation due to the high energy demands of the subsequent ethanol distillation. In the present study, high-yield ethanol production was achieved by short-term liquefaction and fermentation of lignocellulose biomass in a novel drum-type rotary fermentation system using a yeast strain developed for cell-surface display of fungal endoglucanase, cellobiohydrolase, and β-glucosidase. In the presence of 10 FPU/g-biomass cellulase added, the recombinant cellulolytic strain produced 1.4-fold higher ethanol (89% of theoretical yield) from high-solid (200 g-dry weight/L) rice straw within 72 h of fermentation than wild type strain. Cell-surface engineering successfully reduced the amount of commercial enzyme required for the fermentation of cellulose. This study demonstrates that cellulases displayed on the yeast cell surface are capable of hydrolyzing cellulose that was not hydrolyzed by commercial cellulases, leading to increased sugar utilization for improved ethanol production.
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Affiliation(s)
- Yuki Matano
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
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Hasunuma T, Kondo A. Development of yeast cell factories for consolidated bioprocessing of lignocellulose to bioethanol through cell surface engineering. Biotechnol Adv 2011; 30:1207-18. [PMID: 22085593 DOI: 10.1016/j.biotechadv.2011.10.011] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Revised: 10/12/2011] [Accepted: 10/30/2011] [Indexed: 10/15/2022]
Abstract
To build an energy and material secure future, a next generation of renewable fuels produced from lignocellulosic biomass is required. Although lignocellulosic biomass, which represents an abundant, inexpensive and renewable source for bioethanol production, is of great interest as a feedstock, the complicated ethanol production processes involved make the cost of producing bioethanol from it higher compared to corn starch and cane juice. Therefore, consolidated bioprocessing (CBP), which combines enzyme production, saccharification and fermentation in a single step, has gained increased recognition as a potential bioethanol production system. CBP requires a highly engineered microorganism developed for several different process-specific characteristics. The dominant strategy for engineering a CBP biocatalyst is to express multiple components of a cellulolytic system from either fungi or bacteria in the yeast Saccharomyces cerevisiae. The development of recombinant yeast strains displaying cellulases and hemicellulases on the cell surface represents significant progress toward realization of CBP. Regardless of the process used for biomass hydrolysis, CBP-enabling microorganisms encounter a variety of toxic compounds produced during biomass pretreatment that inhibit microbial growth and ethanol yield. Systems biology approaches including disruptome screening, transcriptomics, and metabolomics have been recently exploited to gain insight into the molecular and genetic traits involved in tolerance and adaptation to the fermentation inhibitors. In this review, we focus on recent advances in development of yeast strains with both the ability to directly convert lignocellulosic material to ethanol and tolerance in the harsh environments containing toxic compounds in the presence of ethanol.
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Affiliation(s)
- Tomohisa Hasunuma
- Organization of Advanced Science and Technology, Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
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45
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Sanda T, Hasunuma T, Matsuda F, Kondo A. Repeated-batch fermentation of lignocellulosic hydrolysate to ethanol using a hybrid Saccharomyces cerevisiae strain metabolically engineered for tolerance to acetic and formic acids. BIORESOURCE TECHNOLOGY 2011; 102:7917-24. [PMID: 21704512 DOI: 10.1016/j.biortech.2011.06.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 05/26/2011] [Accepted: 06/06/2011] [Indexed: 05/26/2023]
Abstract
A major challenge associated with the fermentation of lignocellulose-derived hydrolysates is improved ethanol production in the presence of fermentation inhibitors, such as acetic and formic acids. Enhancement of transaldolase (TAL) and formate dehydrogenase (FDH) activities through metabolic engineering successfully conferred resistance to weak acids in a recombinant xylose-fermenting Saccharomyces cerevisiae strain. Moreover, hybridization of the metabolically engineered yeast strain improved ethanol production from xylose in the presence of both 30 mM acetate and 20mM formate. Batch fermentation of lignocellulosic hydrolysate containing a mixture of glucose, fructose and xylose as carbon sources, as well as the fermentation inhibitors, acetate and formate, was performed for five cycles without any loss of fermentation capacity. Long-term stability of ethanol production in the fermentation phase was not only attributed to the coexpression of TAL and FDH genes, but also the hybridization of haploid strains.
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Affiliation(s)
- Tomoya Sanda
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
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