Identification of Mutations Responsible for Improved Xylose Utilization in an Adapted Xylose Isomerase Expressing <i>Saccharomyces cerevisiae</i> Strain

Economic conversion of biomass to biofuels and chemicals requires efficient and complete utilization of xylose. <i>Saccharomyces cerevisiae</i> strains engineered for xylose utilization are still considerably limited in their overall ability to metabolize xylose. In this study, we identi...

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Main Authors: Ronald E. Hector, Jeffrey A. Mertens, Nancy N. Nichols
Format: Article
Language:English
Published: MDPI AG 2022-11-01
Series:Fermentation
Subjects:
Online Access:https://www.mdpi.com/2311-5637/8/12/669
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author Ronald E. Hector
Jeffrey A. Mertens
Nancy N. Nichols
author_facet Ronald E. Hector
Jeffrey A. Mertens
Nancy N. Nichols
author_sort Ronald E. Hector
collection DOAJ
description Economic conversion of biomass to biofuels and chemicals requires efficient and complete utilization of xylose. <i>Saccharomyces cerevisiae</i> strains engineered for xylose utilization are still considerably limited in their overall ability to metabolize xylose. In this study, we identified causative mutations resulting in improved xylose fermentation of an adapted <i>S. cerevisiae</i> strain expressing codon-optimized xylose isomerase and xylulokinase genes from the rumen bacterium <i>Prevotella ruminicola</i>. Genome sequencing identified single-nucleotide polymorphisms in seven open reading frames. Tetrad analysis showed that mutations in both <i>PBS2</i> and <i>PHO13</i> genes were required for increased xylose utilization. Single deletion of either <i>PBS2</i> or <i>PHO13</i> did not improve xylose utilization in strains expressing the xylose isomerase pathway. <i>Saccharomyces</i> can also be engineered for xylose metabolism using the xylose reductase/xylitol dehydrogenase genes from <i>Scheffersomyces stipitis</i>. In strains expressing the xylose reductase pathway, single deletion of <i>PHO13</i> did show a significant increase xylose utilization, and further improvement in growth and fermentation was seen when <i>PBS2</i> was also deleted. These findings will extend the understanding of metabolic limitations for xylose utilization in <i>S. cerevisiae</i> as well as understanding of how they differ among strains engineered with two different xylose utilization pathways.
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spelling doaj.art-7f609930c513483fbfbedb0437b039182023-11-24T14:44:44ZengMDPI AGFermentation2311-56372022-11-0181266910.3390/fermentation8120669Identification of Mutations Responsible for Improved Xylose Utilization in an Adapted Xylose Isomerase Expressing <i>Saccharomyces cerevisiae</i> StrainRonald E. Hector0Jeffrey A. Mertens1Nancy N. Nichols2Bioenergy Research Unit, USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 North University Street, Peoria, IL 61604, USABioenergy Research Unit, USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 North University Street, Peoria, IL 61604, USABioenergy Research Unit, USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 North University Street, Peoria, IL 61604, USAEconomic conversion of biomass to biofuels and chemicals requires efficient and complete utilization of xylose. <i>Saccharomyces cerevisiae</i> strains engineered for xylose utilization are still considerably limited in their overall ability to metabolize xylose. In this study, we identified causative mutations resulting in improved xylose fermentation of an adapted <i>S. cerevisiae</i> strain expressing codon-optimized xylose isomerase and xylulokinase genes from the rumen bacterium <i>Prevotella ruminicola</i>. Genome sequencing identified single-nucleotide polymorphisms in seven open reading frames. Tetrad analysis showed that mutations in both <i>PBS2</i> and <i>PHO13</i> genes were required for increased xylose utilization. Single deletion of either <i>PBS2</i> or <i>PHO13</i> did not improve xylose utilization in strains expressing the xylose isomerase pathway. <i>Saccharomyces</i> can also be engineered for xylose metabolism using the xylose reductase/xylitol dehydrogenase genes from <i>Scheffersomyces stipitis</i>. In strains expressing the xylose reductase pathway, single deletion of <i>PHO13</i> did show a significant increase xylose utilization, and further improvement in growth and fermentation was seen when <i>PBS2</i> was also deleted. These findings will extend the understanding of metabolic limitations for xylose utilization in <i>S. cerevisiae</i> as well as understanding of how they differ among strains engineered with two different xylose utilization pathways.https://www.mdpi.com/2311-5637/8/12/669<i>Saccharomyces</i>xylose isomerasefermentationstrain adaptationmetabolic engineering
spellingShingle Ronald E. Hector
Jeffrey A. Mertens
Nancy N. Nichols
Identification of Mutations Responsible for Improved Xylose Utilization in an Adapted Xylose Isomerase Expressing <i>Saccharomyces cerevisiae</i> Strain
Fermentation
<i>Saccharomyces</i>
xylose isomerase
fermentation
strain adaptation
metabolic engineering
title Identification of Mutations Responsible for Improved Xylose Utilization in an Adapted Xylose Isomerase Expressing <i>Saccharomyces cerevisiae</i> Strain
title_full Identification of Mutations Responsible for Improved Xylose Utilization in an Adapted Xylose Isomerase Expressing <i>Saccharomyces cerevisiae</i> Strain
title_fullStr Identification of Mutations Responsible for Improved Xylose Utilization in an Adapted Xylose Isomerase Expressing <i>Saccharomyces cerevisiae</i> Strain
title_full_unstemmed Identification of Mutations Responsible for Improved Xylose Utilization in an Adapted Xylose Isomerase Expressing <i>Saccharomyces cerevisiae</i> Strain
title_short Identification of Mutations Responsible for Improved Xylose Utilization in an Adapted Xylose Isomerase Expressing <i>Saccharomyces cerevisiae</i> Strain
title_sort identification of mutations responsible for improved xylose utilization in an adapted xylose isomerase expressing i saccharomyces cerevisiae i strain
topic <i>Saccharomyces</i>
xylose isomerase
fermentation
strain adaptation
metabolic engineering
url https://www.mdpi.com/2311-5637/8/12/669
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