Identification of a glucose-insensitive variant of Gal2 from Saccharomyces cerevisiae exhibiting a high pentose transport capacity

AbstractAs abundant carbohydrates in renewable feedstocks, such as pectin-rich and lignocellulosic hydrolysates, the pentoses arabinose and xylose are regarded as important substrates for production of biofuels and chemicals by engineered microbial hosts. Their efficient transport across the cellular membrane is a prerequisite for economically viable fermentation processes. Thus, there is a need for transporter variants exhibiting a high transport rate of pentoses, especially in the presence of glucose, another major constituent of biomass-based feedstocks. Here, we describe a variant of the galactose permease Gal2 from Saccharomyces cerevisiae (Gal2N376Y/M435I), which is fully insensitive to competitive inhibition by glucose, but, at the same time, exhibits an improved transport capacity for xylose compared to the wildtype protein. Due to this unique property, it significantly reduces the fermentation time of a diploid industrial yeast strain engineered for efficient xylose consumption in mixed glucose/xylose media. When the N376Y/M435I mutations are introduced into a Gal2 variant resistant to glucose-induced degradation, the time necessary for the complete consumption of xylose is reduced by approximately 40%. Moreover, Gal2N376Y/M435I confers improved growth of engineered yeast on arabinose. Therefore, it is a valuable addition to the toolbox necessary for valorization of complex carbohydrate mixtures.

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Galacturonic Acid Inhibits the Growth of Saccharomyces cerevisiae on Galactose, Xylose, and Arabinose

Applied and Environmental Microbiology ◽

10.1128/aem.07617-11 ◽

2012 ◽

Vol 78 (15) ◽

pp. 5052-5059 ◽

Cited By ~ 18

Author(s):

Eline H. Huisjes ◽

Erik de Hulster ◽

Jan C. van Dam ◽

Jack T. Pronk ◽

Antonius J. A. van Maris

Keyword(s):

Saccharomyces Cerevisiae ◽

Galacturonic Acid ◽

Competitive Inhibition ◽

Energy Requirement ◽

Major Constituent ◽

Yeast Fermentation ◽

Substrate Uptake ◽

Citrus Peel ◽

Content Type ◽

The Impact

ABSTRACTThe efficient fermentation of mixed substrates is essential for the microbial conversion of second-generation feedstocks, including pectin-rich waste streams such as citrus peel and sugar beet pulp. Galacturonic acid is a major constituent of hydrolysates of these pectin-rich materials. The yeastSaccharomyces cerevisiae, the main producer of bioethanol, cannot use this sugar acid. The impact of galacturonic acid on alcoholic fermentation byS. cerevisiaewas investigated with anaerobic batch cultures grown on mixtures of glucose and galactose at various galacturonic acid concentrations and on a mixture of glucose, xylose, and arabinose. In cultures grown at pH 5.0, which is well above the pKavalue of galacturonic acid (3.51), the addition of 10 g · liter−1galacturonic acid did not affect galactose fermentation kinetics and growth. In cultures grown at pH 3.5, the addition of 10 g · liter−1galacturonic acid did not significantly affect glucose consumption. However, at this lower pH, galacturonic acid completely inhibited growth on galactose and reduced galactose consumption rates by 87%. Additionally, it was shown that galacturonic acid strongly inhibits the fermentation of xylose and arabinose by the engineered pentose-fermentingS. cerevisiaestrain IMS0010. The data indicate that inhibition occurs when nondissociated galacturonic acid is present extracellularly and corroborate the hypothesis that a combination of a decreased substrate uptake rate due to competitive inhibition on Gal2p, an increased energy requirement to maintain cellular homeostasis, and/or an accumulation of galacturonic acid 1-phosphate contributes to the inhibition. The role of galacturonic acid as an inhibitor of sugar fermentation should be considered in the design of yeast fermentation processes based on pectin-rich feedstocks.

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Inhibition of Yeast Growth by Tryptamine and Recovery with Tryptophan

Current Bioactive Compounds ◽

10.2174/1573407214666180713094152 ◽

2020 ◽

Vol 16 (1) ◽

pp. 48-52 ◽

Cited By ~ 1

Author(s):

Chandrika Kadkol ◽

Ian Macreadie

Keyword(s):

Saccharomyces Cerevisiae ◽

Carbon Source ◽

Competitive Inhibition ◽

Yeast Species ◽

Inhibitory Effect ◽

The Body ◽

Inhibitory Effects ◽

Trna Synthetases ◽

Fermentative Growth ◽

Biogenic Monoamine

Background: Tryptamine, a biogenic monoamine that is present in trace levels in the mammalian central nervous system, has probable roles as a neurotransmitter and/or a neuromodulator and may be associated with various neuropsychiatric disorders. One of the ways tryptamine may affect the body is by the competitive inhibition of the attachment of tryptophan to tryptophanyl tRNA synthetases. Methods: This study has explored the effects of tryptamine on growth of six yeast species (Saccharomyces cerevisiae, Candida glabrata, C. krusei, C. dubliniensis, C. tropicalis and C. lusitaniae) in media with glucose or ethanol as the carbon source, as well as recovery of growth inhibition by the addition of tryptophan. Results: Tryptamine was found to have an inhibitory effect on respiratory growth of all yeast species when grown with ethanol as the carbon source. Tryptamine also inhibited fermentative growth of Saccharomyces cerevisiae, C. krusei and C. tropicalis with glucose as the carbon source. In most cases the inhibitory effects were reduced by added tryptophan. Conclusion: The results obtained in this study are consistent with tryptamine competing with tryptophan to bind mitochondrial and cytoplasmic tryptophanyl tRNA synthetases in yeast: effects on mitochondrial and cytoplasmic protein synthesis can be studied as a function of growth with glucose or ethanol as a carbon source. Of the yeast species tested, there is variation in the sensitivity to tryptamine and the rescue by tryptophan. The current study suggests appropriate yeast strains and approaches for further studies.

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Complete and efficient conversion of plant cell wall hemicellulose into high-value bioproducts by engineered yeast

Nature Communications ◽

10.1038/s41467-021-25241-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Liang Sun ◽

Jae Won Lee ◽

Sangdo Yook ◽

Stephan Lane ◽

Ziqiao Sun ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Wall ◽

Plant Cell ◽

Plant Cell Wall ◽

Cellulosic Biomass ◽

Hemicellulose Hydrolysate ◽

Acetyl Coa ◽

Engineered Yeast ◽

Fermentation Inhibitor ◽

Acid Lactone

AbstractPlant cell wall hydrolysates contain not only sugars but also substantial amounts of acetate, a fermentation inhibitor that hinders bioconversion of lignocellulose. Despite the toxic and non-consumable nature of acetate during glucose metabolism, we demonstrate that acetate can be rapidly co-consumed with xylose by engineered Saccharomyces cerevisiae. The co-consumption leads to a metabolic re-configuration that boosts the synthesis of acetyl-CoA derived bioproducts, including triacetic acid lactone (TAL) and vitamin A, in engineered strains. Notably, by co-feeding xylose and acetate, an enginered strain produces 23.91 g/L TAL with a productivity of 0.29 g/L/h in bioreactor fermentation. This strain also completely converts a hemicellulose hydrolysate of switchgrass into 3.55 g/L TAL. These findings establish a versatile strategy that not only transforms an inhibitor into a valuable substrate but also expands the capacity of acetyl-CoA supply in S. cerevisiae for efficient bioconversion of cellulosic biomass.

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The impact of transcription factors Znf1, Sip4, Adr1, Tup1, and Hap4 on xylose alcoholic fermentation in the engineered yeast Saccharomyces cerevisiae

Antonie van Leeuwenhoek ◽

10.1007/s10482-021-01607-6 ◽

2021 ◽

Author(s):

Ljubov Dzanaeva ◽

Barbara Kruk ◽

Justyna Ruchala ◽

Andriy Sibirny ◽

Kostyantyn Dmytruk

Keyword(s):

Saccharomyces Cerevisiae ◽

Transcription Factors ◽

Alcoholic Fermentation ◽

Yeast Saccharomyces Cerevisiae ◽

Engineered Yeast ◽

The Impact

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The Production of Bioethanol from Rimau Gerga Lebong (Rgl) Orange Waste as an Alternative Energy

MATEC Web of Conferences ◽

10.1051/matecconf/201824804004 ◽

2018 ◽

Vol 248 ◽

pp. 04004

Author(s):

Vike Darliyasi ◽

Kurnia Herlina Dewi ◽

Budiyanto

Keyword(s):

Saccharomyces Cerevisiae ◽

Alternative Energy ◽

Block Design ◽

Trichoderma Viride ◽

Total Dissolved Solids ◽

Dissolved Solids ◽

Fermentation Time ◽

Ethanol Content ◽

Significant Difference ◽

Orange Waste

Bioethanol from Rimau Gerga Lebong (RGL) orange waste is one of the solution to overcome fuel oil problem. The aim of this research is to get the type of microorganisms and fermentation time that produce the highest ethanol from RGL orange waste. The research method used was Randomized Block Design (RBD) of two factors, namely type of microorganisms (Trichoderma viride, Saccharomyces cerevisiae, and Trichoderma viride + Saccharomyces cerevisiae) and fermentation time (3 days, 5 days, and 7 days. Within the three type of microorganisms with variations of fermentation time showed that the pH was able to carry out the fermentation process smoothly. The highest total dissolved solids were in the type of Trichoderma viride 3 days and 5 days, and the type of mix of microorganisms on the 3rd day. The highest ethanol content is in the type of Sachharomyces cerevisiae for 7 days. ANOVA result showed that the interaction between two treatments on the total dissolved solids experienced significant differences, so it continue with the DMRT test at a significant level of 0.5%. However, it is different from the results of ANOVA on ethanol content which showed that there were significant differences between ethanol content and types of microorganisms, but there was no significant difference on fermentation time

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Structure and assembly of ESCRT-III helical Vps24 filaments

Science Advances ◽

10.1126/sciadv.aba4897 ◽

2020 ◽

Vol 6 (34) ◽

pp. eaba4897 ◽

Cited By ~ 4

Author(s):

Stefan T. Huber ◽

Siavash Mostafavi ◽

Simon A. Mortensen ◽

Carsten Sachse

Keyword(s):

Saccharomyces Cerevisiae ◽

Mixed Type ◽

Multivesicular Body ◽

Cellular Membrane ◽

Membrane Remodeling ◽

Tubular Structures ◽

Geometric Properties ◽

Open Conformation ◽

Assembly Structure ◽

Polymeric Structures

ESCRT-III proteins mediate a range of cellular membrane remodeling activities such as multivesicular body biogenesis, cytokinesis, and viral release. Critical to these processes is the assembly of ESCRT-III subunits into polymeric structures. In this study, we determined the cryo-EM structure of a helical assembly of Saccharomyces cerevisiae Vps24 at 3.2-Å resolution and found that Vps24 adopts an elongated open conformation. Vps24 forms a domain-swapped dimer extended into protofilaments that associate into a double-stranded apolar filament. We demonstrate that, upon binding negatively charged lipids, Vps24 homopolymer filaments undergo partial disassembly into shorter filament fragments and oligomers. Upon the addition of Vps24, Vps2, and Snf7, liposomes are deformed into neck and tubular structures by an ESCRT-III heteropolymer coat. The filamentous Vps24 homopolymer assembly structure and interaction studies reveal how Vps24 could introduce unique geometric properties to mixed-type ESCRT-III heteropolymers and contribute to the process of membrane scission events.

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Transport-limited fermentation and growth of Saccharomyces cerevisiae and its competitive inhibition

Archives of Microbiology ◽

10.1007/bf00406676 ◽

1967 ◽

Vol 58 (2) ◽

pp. 155-168 ◽

Cited By ~ 101

Author(s):

N. Uden

Keyword(s):

Saccharomyces Cerevisiae ◽

Competitive Inhibition

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Expression of a heterologous xylose transporter in a Saccharomyces cerevisiae strain engineered to utilize xylose improves aerobic xylose consumption

Applied Microbiology and Biotechnology ◽

10.1007/s00253-008-1583-2 ◽

2008 ◽

Vol 80 (4) ◽

pp. 675-684 ◽

Cited By ~ 94

Author(s):

Ronald E. Hector ◽

Nasib Qureshi ◽

Stephen R. Hughes ◽

Michael A. Cotta

Keyword(s):

Saccharomyces Cerevisiae ◽

Xylose Consumption ◽

Xylose Transporter

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Utilization of robusta coffee waste as a renewable energy material - bioetanol

MATEC Web of Conferences ◽

10.1051/matecconf/201815401004 ◽

2018 ◽

Vol 154 ◽

pp. 01004

Author(s):

Sutarno ◽

Abdul Malik Kholiq

Keyword(s):

Saccharomyces Cerevisiae ◽

Renewable Energy ◽

Fermentation Process ◽

Fermentation Time ◽

Coffee Waste ◽

Robusta Coffee ◽

Energy Material ◽

Catalyst Type ◽

Hydrolysis Of

A research on robusta coffee waste has been conducted as a renewable energy material - Bioethanol. This research was carried out by hydrolysis and fermentation process using Zymomonasmobilis and Saccharomyces cerevisiae (Zymomonasmobilis) bacteria to obtain the best catalyst type in the process of hydrolysis of coffee skin to glucose and the effect of fermentation time on bioethanol content produced. This research was conducted by varying the fermentation time of 7 days; 8 days; 9 days and 10 days. The fermentation fluid was then distilled and tested for bioethanol using a refractometer. Furthermore, bioethanol concentration in the analysis using.

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