Special Issue "Yeast Biorefineries"

A special issue of Journal of Fungi (ISSN 2309-608X).

Deadline for manuscript submissions: closed (31 October 2021) | Viewed by 12445

Special Issue Editors

Prof. Dr. Isabel Sá-Correia
E-Mail Website
Guest Editor
Instituto Superior Técnico, Universidade de Lisboa and Institute for Bioengineering and Biosciences, Lisbon, Portugal
Interests: yeast molecular biology and multiomics; yeast physiology; yeast diversity; valorization of bioresidues; development of superior yeasts
Special Issues, Collections and Topics in MDPI journals
Dr. Naseem A. Gaur
E-Mail Website
Guest Editor
International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
Interests: synthetic biology; bioenergy; biofuels; yeast metabolic engineering; C5/C6 fermentation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear colleagues,

Advanced biorefineries have the aim of valorizing biomass and bioresidues from forestry, agriculture, and agrifood industries, among others, into a wide spectrum of biofuels and other bioproducts. They are key to implementing a sustainable bio-based economy, but research and development are still required to obtain environmentally friendly and economically feasible commercial-scale biorefineries. For this reason, this is a very active and exciting area of R&D.

This Special Issue intends to gather the most recent and original research and review papers on the identification, development, and exploitation of robust, metabolically promising, and genetically engineered yeast strains for advanced biorefineries. Saccharomyces cerevisiae is a major cell factory for which vast biological knowledge and genetic tools are available. However, the exploitation of non-Saccharomyces yeasts is recently gaining momentum, making this large and heterogeneous group desirable for the synthesis of a wide range of added-value products, in particular lipids/oleofuels, bioethanol, carotenoids, organic acids, and biopolymers.

Papers on the identification, exploitation, and development of robust, metabolically promising, and genetically engineered conventional and non-conventional yeast strains for biorefineries are welcome. Papers exploring functional and comparative genomics analyses for understanding the physiological genomics of yeasts as cell factories and the development of bioprocesses, especially those dedicated to the valorization of bioresidues and the production of added-value products by yeasts, are also welcome.

Prof. Dr. Isabel Sa-Correia
Dr. Naseem A. Gaur
Guest Editors

Manuscript Submission Information

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Keywords

  • valorization of bio-residues
  • biofuels
  • value added bioproducts
  • yeast biodiversity
  • yeast molecular biology and multiomics
  • yeast physiology
  • bioprocess engineering
  • metabolic engineering
  • synthetic biology

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Published Papers (12 papers)

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Research

Article
Optimization of Carotenoids Production from Rhodotorula sp. Strain ATL72 for Enhancing Its Biotechnological Applications
J. Fungi 2022, 8(2), 160; https://doi.org/10.3390/jof8020160 - 06 Feb 2022
Viewed by 684
Abstract
Rhodotorula yeasts which are known as carotenogenic yeasts have a great industrial value due to their ability to produce carotenoids. In particular, the isolated yeast Rhodotorula sp. (strain ATL72) has been reported to be a promising producer of high concentrations of carotenoids. A [...] Read more.
Rhodotorula yeasts which are known as carotenogenic yeasts have a great industrial value due to their ability to produce carotenoids. In particular, the isolated yeast Rhodotorula sp. (strain ATL72) has been reported to be a promising producer of high concentrations of carotenoids. A combination of central composite design (CCD) and Plackett–Burman (PB) design was used to optimize carotenoids produced by this yeast. The optimum production of carotenoids was completed when the yeast was grown in a production medium composed of 3.7 g/L malt extract, 7.7 g/L fructose, 9 g/L urea, 35 g/L NaCl, and 1 g/L yeast extract at 27.5 °C, pH 6.7, and 180 rpm. Two batch runs in 1 L and 7 L bioreactors were conducted which increased the productivity of carotenoid concentration from 21.5 mg/L after 98 h of incubation at the level of the shake flask to 229.9 mg/L after 47 h of incubation at the level of 7 L bioreactor. The carotenoid pigment was extracted in dimethylsulfoxide (DMSO), acetone, petroleum ether, and sodium chloride, and subsequently identified and characterized using UV-visible scanning, thin layer chromatography, and gas chromatography/mass spectrometry. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
Crosstalk between Yeast Cell Plasma Membrane Ergosterol Content and Cell Wall Stiffness under Acetic Acid Stress Involving Pdr18
J. Fungi 2022, 8(2), 103; https://doi.org/10.3390/jof8020103 - 21 Jan 2022
Cited by 1 | Viewed by 1029
Abstract
Acetic acid is a major inhibitory compound in several industrial bioprocesses, in particular in lignocellulosic yeast biorefineries. Cell envelope remodeling, involving cell wall and plasma membrane composition, structure and function, is among the mechanisms behind yeast adaptation and tolerance to stress. Pdr18 is [...] Read more.
Acetic acid is a major inhibitory compound in several industrial bioprocesses, in particular in lignocellulosic yeast biorefineries. Cell envelope remodeling, involving cell wall and plasma membrane composition, structure and function, is among the mechanisms behind yeast adaptation and tolerance to stress. Pdr18 is a plasma membrane ABC transporter of the pleiotropic drug resistance family and a reported determinant of acetic acid tolerance mediating ergosterol transport. This study provides evidence for the impact of Pdr18 expression in yeast cell wall during adaptation to acetic acid stress. The time-course of acetic-acid-induced transcriptional activation of cell wall biosynthetic genes (FKS1, BGL2, CHS3, GAS1) and of increased cell wall stiffness and cell wall polysaccharide content in cells with the PDR18 deleted, compared to parental cells, is reported. Despite the robust and more intense adaptive response of the pdr18Δ population, the stress-induced increase of cell wall resistance to lyticase activity was below parental strain levels, and the duration of the period required for intracellular pH recovery from acidification and growth resumption was higher in the less tolerant pdr18Δ population. The ergosterol content, critical for plasma membrane stabilization, suffered a drastic reduction in the first hour of cultivation under acetic acid stress, especially in pdr18Δ cells. Results revealed a crosstalk between plasma membrane ergosterol content and cell wall biophysical properties, suggesting a coordinated response to counteract the deleterious effects of acetic acid. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
Saccharomyces cerevisiae Cells Lacking the Zinc Vacuolar Transporter Zrt3 Display Improved Ethanol Productivity in Lignocellulosic Hydrolysates
J. Fungi 2022, 8(1), 78; https://doi.org/10.3390/jof8010078 - 14 Jan 2022
Cited by 1 | Viewed by 554
Abstract
Yeast-based bioethanol production from lignocellulosic hydrolysates (LH) is an attractive and sustainable alternative for biofuel production. However, the presence of acetic acid (AA) in LH is still a major problem. Indeed, above certain concentrations, AA inhibits yeast fermentation and triggers a regulated cell [...] Read more.
Yeast-based bioethanol production from lignocellulosic hydrolysates (LH) is an attractive and sustainable alternative for biofuel production. However, the presence of acetic acid (AA) in LH is still a major problem. Indeed, above certain concentrations, AA inhibits yeast fermentation and triggers a regulated cell death (RCD) process mediated by the mitochondria and vacuole. Understanding the mechanisms involved in AA-induced RCD (AA-RCD) may thus help select robust fermentative yeast strains, providing novel insights to improve lignocellulosic ethanol (LE) production. Herein, we hypothesized that zinc vacuolar transporters are involved in vacuole-mediated AA-RCD, since zinc enhances ethanol production and zinc-dependent catalase and superoxide dismutase protect from AA-RCD. In this work, zinc limitation sensitized wild-type cells to AA-RCD, while zinc supplementation resulted in a small protective effect. Cells lacking the vacuolar zinc transporter Zrt3 were highly resistant to AA-RCD, exhibiting reduced vacuolar dysfunction. Moreover, zrt3Δ cells displayed higher ethanol productivity than their wild-type counterparts, both when cultivated in rich medium with AA (0.29 g L−1 h−1 versus 0.11 g L−1 h−1) and in an LH (0.73 g L−1 h−1 versus 0.55 g L−1 h−1). Overall, the deletion of ZRT3 emerges as a promising strategy to increase strain robustness in LE industrial production. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
Phenotypic Characterization and Comparative Genomics of the Melanin-Producing Yeast Exophiala lecanii-corni Reveals a Distinct Stress Tolerance Profile and Reduced Ribosomal Genetic Content
J. Fungi 2021, 7(12), 1078; https://doi.org/10.3390/jof7121078 - 15 Dec 2021
Viewed by 828
Abstract
The black yeast Exophiala lecanii-corni of the order Chaetothyriales is notable for its ability to produce abundant quantities of DHN-melanin. While many other Exophiala species are frequent causal agents of human infection, E. lecanii-corni CBS 102400 lacks the thermotolerance requirements that enable pathogenicity, [...] Read more.
The black yeast Exophiala lecanii-corni of the order Chaetothyriales is notable for its ability to produce abundant quantities of DHN-melanin. While many other Exophiala species are frequent causal agents of human infection, E. lecanii-corni CBS 102400 lacks the thermotolerance requirements that enable pathogenicity, making it appealing for use in targeted functional studies and biotechnological applications. Here, we report the stress tolerance characteristics of E. lecanii-corni, with an emphasis on the influence of melanin on its resistance to various forms of stress. We find that E. lecanii-corni has a distinct stress tolerance profile that includes variation in resistance to temperature, osmotic, and oxidative stress relative to the extremophilic and pathogenic black yeast Exophiala dermatitidis. Notably, the presence of melanin substantially impacts stress resistance in E. lecanii-corni, while this was not found to be the case in E. dermatitidis. The cellular context, therefore, influences the role of melanin in stress protection. In addition, we present a detailed analysis of the E. lecanii-corni genome, revealing key differences in functional genetic content relative to other ascomycetous species, including a significant decrease in abundance of genes encoding ribosomal proteins. In all, this study provides insight into how genetics and physiology may underlie stress tolerance and enhances understanding of the genetic diversity of black yeasts. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
Establishment of Kluyveromyces marxianus as a Microbial Cell Factory for Lignocellulosic Processes: Production of High Value Furan Derivatives
J. Fungi 2021, 7(12), 1047; https://doi.org/10.3390/jof7121047 - 07 Dec 2021
Cited by 1 | Viewed by 862
Abstract
The establishment of lignocellulosic biorefineries is dependent on microorganisms being able to cope with the stressful conditions resulting from the release of inhibitory compounds during biomass processing. The yeast Kluyveromyces marxianus has been explored as an alternative microbial factory due to its thermotolerance [...] Read more.
The establishment of lignocellulosic biorefineries is dependent on microorganisms being able to cope with the stressful conditions resulting from the release of inhibitory compounds during biomass processing. The yeast Kluyveromyces marxianus has been explored as an alternative microbial factory due to its thermotolerance and ability to natively metabolize xylose. The lignocellulose-derived inhibitors furfural and 5-hydroxymethylfurfural (HMF) are considered promising building-block platforms that can be converted into a wide variety of high-value derivatives. Here, several K. marxianus strains, isolated from cocoa fermentation, were evaluated for xylose consumption and tolerance towards acetic acid, furfural, and HMF. The potential of this yeast to reduce furfural and HMF at high inhibitory loads was disclosed and characterized. Our results associated HMF reduction with NADPH while furfural-reducing activity was higher with NADH. In addition, furans’ inhibitory effect was higher when combined with xylose consumption. The furan derivatives produced by K. marxianus in different conditions were identified. Furthermore, one selected isolate was efficiently used as a whole-cell biocatalyst to convert furfural and HMF into their derivatives, furfuryl alcohol and 2,5-bis(hydroxymethyl)furan (BHMF), with high yields and productivities. These results validate K. marxianus as a promising microbial platform in lignocellulosic biorefineries. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
Metabolomic Profiling Revealed Diversion of Cytidinediphosphate-Diacylglycerol and Glycerol Pathway towards Denovo Triacylglycerol Synthesis in Rhodosporidium toruloides
J. Fungi 2021, 7(11), 967; https://doi.org/10.3390/jof7110967 - 13 Nov 2021
Viewed by 842
Abstract
Oleaginous yeast Rhodosporidium toruloides has great biotechnological potential and scientific interest, yet the molecular rationale of its cellular behavior to carbon and nitrogen ratios with concurrent lipid agglomeration remains elusive. Here, metabolomics adaptations of the R. toruloides in response to varying glucose and [...] Read more.
Oleaginous yeast Rhodosporidium toruloides has great biotechnological potential and scientific interest, yet the molecular rationale of its cellular behavior to carbon and nitrogen ratios with concurrent lipid agglomeration remains elusive. Here, metabolomics adaptations of the R. toruloides in response to varying glucose and nitrogen concentrations have been investigated. In preliminary screening we found that 5% glucose (w/v) was optimal for further analysis in Rhodosporidium toruloides 3641. Hereafter, the effect of complementation to increase lipid agglomeration was evaluated with different nitrogen sources and their concentration. The results obtained illustrated that the biomass (13 g/L) and lipid (9.1 g/L) production were maximum on 5% (w/v) glucose and 0.12% (NH4)2SO4. Furthermore, to shed lights on lipid accumulation induced by nitrogen-limitation, we performed metabolomic analysis of the oleaginous yeast R. toruloides 3641. Significant changes were observed in metabolite concentrations by qualitative metabolomics through gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), which were mapped onto the governing metabolic pathways. Notable finding in this strain concerns glycerol and CDP-DAG metabolism wherein reduced production of glycerol and phospholipids induced a bypass leading to enhanced de-novo triacylglyceride synthesis. Collectively, our findings help in understanding the central carbon metabolism of R. toruloides which may assist in developing rationale metabolic models and engineering efforts in this organism. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
l-Lactic Acid Production Using Engineered Saccharomyces cerevisiae with Improved Organic Acid Tolerance
J. Fungi 2021, 7(11), 928; https://doi.org/10.3390/jof7110928 - 31 Oct 2021
Viewed by 995
Abstract
Lactic acid is mainly used to produce bio-based, bio-degradable polylactic acid. For industrial production of lactic acid, engineered Saccharomyces cerevisiae can be used. To avoid cellular toxicity caused by lactic acid accumulation, pH-neutralizing agents are used, leading to increased production costs. In this [...] Read more.
Lactic acid is mainly used to produce bio-based, bio-degradable polylactic acid. For industrial production of lactic acid, engineered Saccharomyces cerevisiae can be used. To avoid cellular toxicity caused by lactic acid accumulation, pH-neutralizing agents are used, leading to increased production costs. In this study, lactic acid-producing S. cerevisiae BK01 was developed with improved lactic acid tolerance through adaptive laboratory evolution (ALE) on 8% lactic acid. The genetic basis of BK01 could not be determined, suggesting complex mechanisms associated with lactic acid tolerance. However, BK01 had distinctive metabolomic traits clearly separated from the parental strain, and lactic acid production was improved by 17% (from 102 g/L to 119 g/L). To the best of our knowledge, this is the highest lactic acid titer produced by engineered S. cerevisiae without the use of pH neutralizers. Moreover, cellulosic lactic acid production by BK01 was demonstrated using acetate-rich buckwheat husk hydrolysates. Particularly, BK01 revealed improved tolerance against acetic acid of the hydrolysates, a major fermentation inhibitor of lignocellulosic biomass. In short, ALE with a high concentration of lactic acid improved lactic acid production as well as acetic acid tolerance of BK01, suggesting a potential for economically viable cellulosic lactic acid production. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
Identification of the Aldo-Keto Reductase Responsible for d-Galacturonic Acid Conversion to l-Galactonate in Saccharomyces cerevisiae
J. Fungi 2021, 7(11), 914; https://doi.org/10.3390/jof7110914 - 27 Oct 2021
Viewed by 785
Abstract
d-galacturonic acid (d-GalUA) is the main constituent of pectin, a complex polysaccharide abundant in several agro-industrial by-products such as sugar beet pulp or citrus peel. During several attempts to valorise d-GalUA by engineering the popular cell factory Saccharomyces cerevisiae [...] Read more.
d-galacturonic acid (d-GalUA) is the main constituent of pectin, a complex polysaccharide abundant in several agro-industrial by-products such as sugar beet pulp or citrus peel. During several attempts to valorise d-GalUA by engineering the popular cell factory Saccharomyces cerevisiae, it became obvious that d-GalUA is, to a certain degree, converted to l-galactonate (l-GalA) by an endogenous enzymatic activity. The goal of the current work was to clarify the identity of the responsible enzyme(s). A protein homology search identified three NADPH-dependent unspecific aldo-keto reductases in baker’s yeast (encoded by GCY1, YPR1 and GRE3) that show sequence similarities to known d-GalUA reductases from filamentous fungi. Characterization of the respective deletion mutants and an in vitro enzyme assay with a Gcy1 overproducing strain verified that Gcy1 is mainly responsible for the detectable reduction of d-GalUA to l-GalA. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
Genome Sequence Analysis of the Oleaginous Yeast, Rhodotorula diobovata, and Comparison of the Carotenogenic and Oleaginous Pathway Genes and Gene Products with Other Oleaginous Yeasts
J. Fungi 2021, 7(4), 320; https://doi.org/10.3390/jof7040320 - 20 Apr 2021
Cited by 1 | Viewed by 1067
Abstract
Rhodotorula diobovata is an oleaginous and carotenogenic yeast, useful for diverse biotechnological applications. To understand the molecular basis of its potential applications, the genome was sequenced using the Illumina MiSeq and Ion Torrent platforms, assembled by AbySS, and annotated using the JGI annotation [...] Read more.
Rhodotorula diobovata is an oleaginous and carotenogenic yeast, useful for diverse biotechnological applications. To understand the molecular basis of its potential applications, the genome was sequenced using the Illumina MiSeq and Ion Torrent platforms, assembled by AbySS, and annotated using the JGI annotation pipeline. The genome size, 21.1 MB, was similar to that of the biotechnological “workhorse”, R. toruloides. Comparative analyses of the R. diobovata genome sequence with those of other Rhodotorula species, Yarrowia lipolytica, Phaffia rhodozyma, Lipomyces starkeyi, and Sporidiobolus salmonicolor, were conducted, with emphasis on the carotenoid and neutral lipid biosynthesis pathways. Amino acid sequence alignments of key enzymes in the lipid biosynthesis pathway revealed why the activity of malic enzyme and ATP-citrate lyase may be ambiguous in Y. lipolytica and L. starkeyi. Phylogenetic analysis showed a close relationship between R. diobovata and R. graminis WP1. Dot-plot analysis of the coding sequences of the genes crtYB and ME1 corroborated sequence homologies between sequences from R. diobovata and R. graminis. There was, however, nonsequential alignment between crtYB CDS sequences from R. diobovata and those from X. dendrorhous. This research presents the first genome analysis of R. diobovata with a focus on its biotechnological potential as a lipid and carotenoid producer. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
Complete Utilization of the Major Carbon Sources Present in Sugar Beet Pulp Hydrolysates by the Oleaginous Red Yeasts Rhodotorula toruloides and R. mucilaginosa
J. Fungi 2021, 7(3), 215; https://doi.org/10.3390/jof7030215 - 17 Mar 2021
Cited by 8 | Viewed by 1089
Abstract
Agro-industrial residues are low-cost carbon sources (C-sources) for microbial growth and production of value-added bioproducts. Among the agro-industrial residues available, those rich in pectin are generated in high amounts worldwide from the sugar industry or the industrial processing of fruits and vegetables. Sugar [...] Read more.
Agro-industrial residues are low-cost carbon sources (C-sources) for microbial growth and production of value-added bioproducts. Among the agro-industrial residues available, those rich in pectin are generated in high amounts worldwide from the sugar industry or the industrial processing of fruits and vegetables. Sugar beet pulp (SBP) hydrolysates contain predominantly the neutral sugars d-glucose, l-arabinose and d-galactose, and the acidic sugar d-galacturonic acid. Acetic acid is also present at significant concentrations since the d-galacturonic acid residues are acetylated. In this study, we have examined and optimized the performance of a Rhodotorula mucilaginosa strain, isolated from SBP and identified at the molecular level during this work. This study was extended to another oleaginous red yeast species, R. toruloides, envisaging the full utilization of the C-sources from SBP hydrolysate (at pH 5.0). The dual role of acetic acid as a carbon and energy source and as a growth and metabolism inhibitor was examined. Acetic acid prevented the catabolism of d-galacturonic acid and l-arabinose after the complete use of the other C-sources. However, d-glucose and acetic acid were simultaneously and efficiently metabolized, followed by d-galactose. SBP hydrolysate supplementation with amino acids was crucial to allow d-galacturonic acid and l-arabinose catabolism. SBP valorization through the production of lipids and carotenoids by Rhodotorula strains, supported by complete catabolism of the major C-sources present, looks promising for industrial implementation. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
Ethanol Production from Wheat Straw Hydrolysate by Issatchenkia Orientalis Isolated from Waste Cooking Oil
J. Fungi 2021, 7(2), 121; https://doi.org/10.3390/jof7020121 - 06 Feb 2021
Cited by 1 | Viewed by 1040
Abstract
The interest in using non-conventional yeasts to produce value-added compounds from low cost substrates, such as lignocellulosic materials, has increased in recent years. Setting out to discover novel microbial strains that can be used in biorefineries, an Issatchenkia orientalis strain was isolated from [...] Read more.
The interest in using non-conventional yeasts to produce value-added compounds from low cost substrates, such as lignocellulosic materials, has increased in recent years. Setting out to discover novel microbial strains that can be used in biorefineries, an Issatchenkia orientalis strain was isolated from waste cooking oil (WCO) and its capability to produce ethanol from wheat straw hydrolysate (WSHL) was analyzed. As with previously isolated I. orientalis strains, WCO-isolated I. orientalis KJ27-7 is thermotolerant. It grows well at elevated temperatures up to 42 °C. Furthermore, spot drop tests showed that it is tolerant to various chemical fermentation inhibitors that are derived from the pre-treatment of lignocellulosic materials. I. orientalis KJ27-7 is particularly tolerant to acetic acid (up to 75 mM) and tolerates 10 mM formic acid, 5 mM furfural and 10 mM hydroxymethylfurfural. Important for biotechnological cellulosic ethanol production, I. orientalis KJ27-7 grows well on plates containing up to 10% ethanol and media containing up to 90% WSHL. As observed in shake flask fermentations, the specific ethanol productivity correlates with WSHL concentrations. In 90% WSHL media, I. orientalis KJ27-7 produced 10.3 g L−1 ethanol within 24 h. This corresponds to a product yield of 0.50 g g−1 glucose (97% of the theoretical maximum) and a volumetric productivity of 0.43 g L−1 h−1. Therefore, I. orientalis KJ27-7 is an efficient producer of lignocellulosic ethanol from WSHL. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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Article
The Identification of Genetic Determinants of Methanol Tolerance in Yeast Suggests Differences in Methanol and Ethanol Toxicity Mechanisms and Candidates for Improved Methanol Tolerance Engineering
J. Fungi 2021, 7(2), 90; https://doi.org/10.3390/jof7020090 - 27 Jan 2021
Cited by 3 | Viewed by 1342
Abstract
Methanol is a promising feedstock for metabolically competent yeast strains-based biorefineries. However, methanol toxicity can limit the productivity of these bioprocesses. Therefore, the identification of genes whose expression is required for maximum methanol tolerance is important for mechanistic insights and rational genomic manipulation [...] Read more.
Methanol is a promising feedstock for metabolically competent yeast strains-based biorefineries. However, methanol toxicity can limit the productivity of these bioprocesses. Therefore, the identification of genes whose expression is required for maximum methanol tolerance is important for mechanistic insights and rational genomic manipulation to obtain more robust methylotrophic yeast strains. The present chemogenomic analysis was performed with this objective based on the screening of the Euroscarf Saccharomyces cerevisiae haploid deletion mutant collection to search for susceptibility phenotypes in YPD medium supplemented with 8% (v/v) methanol, at 35 °C, compared with an equivalent ethanol concentration (5.5% (v/v)). Around 400 methanol tolerance determinants were identified, 81 showing a marked phenotype. The clustering of the identified tolerance genes indicates an enrichment of functional categories in the methanol dataset not enriched in the ethanol dataset, such as chromatin remodeling, DNA repair and fatty acid biosynthesis. Several genes involved in DNA repair (eight RAD genes), identified as specific for methanol toxicity, were previously reported as tolerance determinants for formaldehyde, a methanol detoxification pathway intermediate. This study provides new valuable information on genes and potential regulatory networks involved in overcoming methanol toxicity. This knowledge is an important starting point for the improvement of methanol tolerance in yeasts capable of catabolizing and copying with methanol concentrations present in promising bioeconomy feedstocks, including industrial residues. Full article
(This article belongs to the Special Issue Yeast Biorefineries)
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