{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/108309"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/108309","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Engineering yeast to synthesize high-value natural products from plant cell wall","abstract":"Second-generation bioenergy and biorefineries based on ligonocellulosic plant materials offers a promising solution to address global concerns about limited natural resources and climate change. Economically feasible production of biofuels and chemicals from plant biomass requires complete and efficient bioconversion of cellulosic substrates. However, none of the industrially preferred microorganisms is capable of fermenting cellulosic carbon economically. Besides, the presence of acetic acid in cellulosic hydrolysate hampered the yields of target products. In addition, product range of existing microbial yeast factories is far from enough to compete with the vetted petroleum-based refineries and chemical synthesis. The overall goal of this thesis study is to develop metabolically engineered yeast platforms and novel strategies for diversifying product range, detoxifying acetic acid, and expanding substrate utilization of plant biomass hydrolysates. First, the respiratory nature of xylose metabolism in engineered Saccharomyces cerevisiae was explored and harnessed for high-level production of β-carotene. Subsequently, we illustrated efficient conversion of xylose-enriched biosorghum hydrolysates into β-carotene by this engineered strain. Next, vitamin A production was established and maximized by addressing challenges including limited acetyl-CoA supply and confined intracellular storage through xylose utilization and two-phase in situ extraction. Furthermore, we demonstrated that xylose metabolism enables efficient co-consumption of acetate under aerobic conditions, arousing an innovative strategy for expanding the capacity of acetyl-CoA supply in Saccharomyces cerevisiae and empowering complete conversion of hemicellulose fractions from switchgrass biomass. This strategy detoxifies acetate as a valuable substrate and facilitates the production of triacetic acid lactone and vitamin A to unprecedented levels reported for S. cerevisiae. Lastly, a xylodextrin-utilizing yeast strain was constructed and its xylodextrin metabolism was improved through rational and evolutionary engineering. The evolved strain with enhanced xylodextrin consumption was further engineered for β-carotene production from Miscanthus autohydrolysates prepared by liquid hot water pretreatment. The engineered yeast strains and strategies described in this study would contribute to economically sustainable conversion of cellulosic carbon sources into valuable natural products.","abstract_html":"Second-generation bioenergy and biorefineries based on ligonocellulosic plant materials offers a promising solution to address global concerns about limited natural resources and climate change. Economically feasible production of biofuels and chemicals from plant biomass requires complete and efficient bioconversion of cellulosic substrates. However, none of the industrially preferred microorganisms is capable of fermenting cellulosic carbon economically. Besides, the presence of acetic acid in cellulosic hydrolysate hampered the yields of target products. In addition, product range of existing microbial yeast factories is far from enough to compete with the vetted petroleum-based refineries and chemical synthesis. The overall goal of this thesis study is to develop metabolically engineered yeast platforms and novel strategies for diversifying product range, detoxifying acetic acid, and expanding substrate utilization of plant biomass hydrolysates. First, the respiratory nature of xylose metabolism in engineered Saccharomyces cerevisiae was explored and harnessed for high-level production of β-carotene. Subsequently, we illustrated efficient conversion of xylose-enriched biosorghum hydrolysates into β-carotene by this engineered strain. Next, vitamin A production was established and maximized by addressing challenges including limited acetyl-CoA supply and confined intracellular storage through xylose utilization and two-phase in situ extraction. Furthermore, we demonstrated that xylose metabolism enables efficient co-consumption of acetate under aerobic conditions, arousing an innovative strategy for expanding the capacity of acetyl-CoA supply in Saccharomyces cerevisiae and empowering complete conversion of hemicellulose fractions from switchgrass biomass. This strategy detoxifies acetate as a valuable substrate and facilitates the production of triacetic acid lactone and vitamin A to unprecedented levels reported for S. cerevisiae. Lastly, a xylodextrin-utilizing yeast strain was constructed and its xylodextrin metabolism was improved through rational and evolutionary engineering. The evolved strain with enhanced xylodextrin consumption was further engineered for β-carotene production from Miscanthus autohydrolysates prepared by liquid hot water pretreatment. The engineered yeast strains and strategies described in this study would contribute to economically sustainable conversion of cellulosic carbon sources into valuable natural products.","abstract_has_math":false,"creators":["Sun, Liang"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Food Science & Human Nutrition","degree_department":null,"school":null,"contributors":["Jin, Yong-Su","Miller, Michael J.","Rao, Christopher V","Erdman, John W"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-08-27T00:51:22Z","date_published":"2020-08-27T00:51:22Z","updated_at":"2026-07-22T22:24:48Z","subjects":["Yeast Saccharomyces cerevisiae, Metabolic engineering, Lignocellulose biomass, Hemicellulose, Xylose, Xylodextrin, Acetate, Acetyl-CoA, Natural products, β-carotene, Vitamin A, Triacetic acid lactone"],"languages":["en"],"rights":["Copyright © 2020 Liang Sun"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/108309","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Jin, Yong-Su","Miller, Michael J.","Rao, Christopher V","Erdman, John W"]},{"key":"dc:creator","label":"Author","values":["Sun, Liang"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-08-27T00:51:22Z","2022-08-27T00:51:40Z","2020-05-07","2020-05"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Food Science & Human Nutrition"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Yeast Saccharomyces cerevisiae, Metabolic engineering, Lignocellulose biomass, Hemicellulose, Xylose, Xylodextrin, Acetate, Acetyl-CoA, Natural products, β-carotene, Vitamin A, Triacetic acid lactone"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright © 2020 Liang Sun"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/108309"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Second-generation bioenergy and biorefineries based on ligonocellulosic plant materials offers a promising solution to address global concerns about limited natural resources and climate change. Economically feasible production of biofuels and chemicals from plant biomass requires complete and efficient bioconversion of cellulosic substrates. However, none of the industrially preferred microorganisms is capable of fermenting cellulosic carbon economically. Besides, the presence of acetic acid in cellulosic hydrolysate hampered the yields of target products. In addition, product range of existing microbial yeast factories is far from enough to compete with the vetted petroleum-based refineries and chemical synthesis. The overall goal of this thesis study is to develop metabolically engineered yeast platforms and novel strategies for diversifying product range, detoxifying acetic acid, and expanding substrate utilization of plant biomass hydrolysates. First, the respiratory nature of xylose metabolism in engineered Saccharomyces cerevisiae was explored and harnessed for high-level production of β-carotene. Subsequently, we illustrated efficient conversion of xylose-enriched biosorghum hydrolysates into β-carotene by this engineered strain. Next, vitamin A production was established and maximized by addressing challenges including limited acetyl-CoA supply and confined intracellular storage through xylose utilization and two-phase in situ extraction. Furthermore, we demonstrated that xylose metabolism enables efficient co-consumption of acetate under aerobic conditions, arousing an innovative strategy for expanding the capacity of acetyl-CoA supply in Saccharomyces cerevisiae and empowering complete conversion of hemicellulose fractions from switchgrass biomass. This strategy detoxifies acetate as a valuable substrate and facilitates the production of triacetic acid lactone and vitamin A to unprecedented levels reported for S. cerevisiae. Lastly, a xylodextrin-utilizing yeast strain was constructed and its xylodextrin metabolism was improved through rational and evolutionary engineering. The evolved strain with enhanced xylodextrin consumption was further engineered for β-carotene production from Miscanthus autohydrolysates prepared by liquid hot water pretreatment. The engineered yeast strains and strategies described in this study would contribute to economically sustainable conversion of cellulosic carbon sources into valuable natural products.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-05-01","The student, Liang Sun, accepted the attached license on 2020-05-06 at 12:14.","The student, Liang Sun, submitted this Dissertation for approval on 2020-05-06 at 12:16.","This Dissertation was approved for publication on 2020-05-07 at 07:32.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15199 on 2020-08-25 at 17:42:49","Made available in DSpace on 2020-08-27T00:51:22Z (GMT). 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Economically feasible production of biofuels and chemicals from plant biomass requires complete and efficient bioconversion of cellulosic substrates. However, none of the industrially preferred microorganisms is capable of fermenting cellulosic carbon economically. Besides, the presence of acetic acid in cellulosic hydrolysate hampered the yields of target products. In addition, product range of existing microbial yeast factories is far from enough to compete with the vetted petroleum-based refineries and chemical synthesis. The overall goal of this thesis study is to develop metabolically engineered yeast platforms and novel strategies for diversifying product range, detoxifying acetic acid, and expanding substrate utilization of plant biomass hydrolysates. First, the respiratory nature of xylose metabolism in engineered Saccharomyces cerevisiae was explored and harnessed for high-level production of β-carotene. Subsequently, we illustrated efficient conversion of xylose-enriched biosorghum hydrolysates into β-carotene by this engineered strain. Next, vitamin A production was established and maximized by addressing challenges including limited acetyl-CoA supply and confined intracellular storage through xylose utilization and two-phase in situ extraction. Furthermore, we demonstrated that xylose metabolism enables efficient co-consumption of acetate under aerobic conditions, arousing an innovative strategy for expanding the capacity of acetyl-CoA supply in Saccharomyces cerevisiae and empowering complete conversion of hemicellulose fractions from switchgrass biomass. This strategy detoxifies acetate as a valuable substrate and facilitates the production of triacetic acid lactone and vitamin A to unprecedented levels reported for S. cerevisiae. Lastly, a xylodextrin-utilizing yeast strain was constructed and its xylodextrin metabolism was improved through rational and evolutionary engineering. The evolved strain with enhanced xylodextrin consumption was further engineered for β-carotene production from Miscanthus autohydrolysates prepared by liquid hot water pretreatment. The engineered yeast strains and strategies described in this study would contribute to economically sustainable conversion of cellulosic carbon sources into valuable natural products.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-05-01","The student, Liang Sun, accepted the attached license on 2020-05-06 at 12:14.","The student, Liang Sun, submitted this Dissertation for approval on 2020-05-06 at 12:16.","This Dissertation was approved for publication on 2020-05-07 at 07:32.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15199 on 2020-08-25 at 17:42:49","Made available in DSpace on 2020-08-27T00:51:22Z (GMT). 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