Promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in Saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomass

Abstract Background Understanding the global metabolic network, significantly perturbed upon promiscuous activities of foreign enzymes and different carbon sources, is crucial for systematic optimization of metabolic engineering of yeast Saccharomyces cerevisiae. Here, we studied the effects of prom...

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Main Authors: Eun Ju Yun, Eun Joong Oh, Jing-Jing Liu, Sora Yu, Dong Hyun Kim, Suryang Kwak, Kyoung Heon Kim, Yong-Su Jin
Format: Article
Language:English
Published: BMC 2018-05-01
Series:Biotechnology for Biofuels
Subjects:
Online Access:http://link.springer.com/article/10.1186/s13068-018-1135-7
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spelling doaj-8079086c39c64d8794e73d76187e9e992020-11-24T21:10:31ZengBMCBiotechnology for Biofuels1754-68342018-05-0111111410.1186/s13068-018-1135-7Promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in Saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomassEun Ju Yun0Eun Joong Oh1Jing-Jing Liu2Sora Yu3Dong Hyun Kim4Suryang Kwak5Kyoung Heon Kim6Yong-Su Jin7Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-ChampaignCarl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-ChampaignCarl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-ChampaignDepartment of Biotechnology, Graduate School, Korea UniversityDepartment of Biotechnology, Graduate School, Korea UniversityCarl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-ChampaignDepartment of Biotechnology, Graduate School, Korea UniversityCarl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-ChampaignAbstract Background Understanding the global metabolic network, significantly perturbed upon promiscuous activities of foreign enzymes and different carbon sources, is crucial for systematic optimization of metabolic engineering of yeast Saccharomyces cerevisiae. Here, we studied the effects of promiscuous activities of overexpressed enzymes encoded by foreign genes on rerouting of metabolic fluxes of an engineered yeast capable of assimilating sugars from renewable biomass by profiling intracellular and extracellular metabolites. Results Unbiased metabolite profiling of the engineered S. cerevisiae strain EJ4 revealed promiscuous enzymatic activities of xylose reductase and xylitol dehydrogenase on galactose and galactitol, respectively, resulting in accumulation of galactitol and tagatose during galactose fermentation. Moreover, during glucose fermentation, a trisaccharide consisting of glucose accumulated outside of the cells probably owing to the promiscuous and transglycosylation activity of β-glucosidase expressed for hydrolyzing cellobiose. Meanwhile, higher accumulation of fatty acids and secondary metabolites was observed during xylose and cellobiose fermentations, respectively. Conclusions The heterologous enzymes functionally expressed in S. cerevisiae showed promiscuous activities that led to unintended metabolic rerouting in strain EJ4. Such metabolic rerouting could result in a low yield and productivity of a final product due to the formation of unexpected metabolites. Furthermore, the global metabolic network can be significantly regulated by carbon sources, thus yielding different patterns of metabolite production. This metabolomic study can provide useful information for yeast strain improvement and systematic optimization of yeast metabolism to manufacture bio-based products.http://link.springer.com/article/10.1186/s13068-018-1135-7Metabolite profilingSaccharomyces cerevisiaeRenewable biomassCarbon sourcePromiscuous activityAutophagy
collection DOAJ
language English
format Article
sources DOAJ
author Eun Ju Yun
Eun Joong Oh
Jing-Jing Liu
Sora Yu
Dong Hyun Kim
Suryang Kwak
Kyoung Heon Kim
Yong-Su Jin
spellingShingle Eun Ju Yun
Eun Joong Oh
Jing-Jing Liu
Sora Yu
Dong Hyun Kim
Suryang Kwak
Kyoung Heon Kim
Yong-Su Jin
Promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in Saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomass
Biotechnology for Biofuels
Metabolite profiling
Saccharomyces cerevisiae
Renewable biomass
Carbon source
Promiscuous activity
Autophagy
author_facet Eun Ju Yun
Eun Joong Oh
Jing-Jing Liu
Sora Yu
Dong Hyun Kim
Suryang Kwak
Kyoung Heon Kim
Yong-Su Jin
author_sort Eun Ju Yun
title Promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in Saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomass
title_short Promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in Saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomass
title_full Promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in Saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomass
title_fullStr Promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in Saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomass
title_full_unstemmed Promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in Saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomass
title_sort promiscuous activities of heterologous enzymes lead to unintended metabolic rerouting in saccharomyces cerevisiae engineered to assimilate various sugars from renewable biomass
publisher BMC
series Biotechnology for Biofuels
issn 1754-6834
publishDate 2018-05-01
description Abstract Background Understanding the global metabolic network, significantly perturbed upon promiscuous activities of foreign enzymes and different carbon sources, is crucial for systematic optimization of metabolic engineering of yeast Saccharomyces cerevisiae. Here, we studied the effects of promiscuous activities of overexpressed enzymes encoded by foreign genes on rerouting of metabolic fluxes of an engineered yeast capable of assimilating sugars from renewable biomass by profiling intracellular and extracellular metabolites. Results Unbiased metabolite profiling of the engineered S. cerevisiae strain EJ4 revealed promiscuous enzymatic activities of xylose reductase and xylitol dehydrogenase on galactose and galactitol, respectively, resulting in accumulation of galactitol and tagatose during galactose fermentation. Moreover, during glucose fermentation, a trisaccharide consisting of glucose accumulated outside of the cells probably owing to the promiscuous and transglycosylation activity of β-glucosidase expressed for hydrolyzing cellobiose. Meanwhile, higher accumulation of fatty acids and secondary metabolites was observed during xylose and cellobiose fermentations, respectively. Conclusions The heterologous enzymes functionally expressed in S. cerevisiae showed promiscuous activities that led to unintended metabolic rerouting in strain EJ4. Such metabolic rerouting could result in a low yield and productivity of a final product due to the formation of unexpected metabolites. Furthermore, the global metabolic network can be significantly regulated by carbon sources, thus yielding different patterns of metabolite production. This metabolomic study can provide useful information for yeast strain improvement and systematic optimization of yeast metabolism to manufacture bio-based products.
topic Metabolite profiling
Saccharomyces cerevisiae
Renewable biomass
Carbon source
Promiscuous activity
Autophagy
url http://link.springer.com/article/10.1186/s13068-018-1135-7
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