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High‐throughput sequencing reveals adaptation‐induced mutations in pentose‐fermenting strains of Zymomonas mobilis
Author(s) -
Dunn Kori L.,
Rao Christopher V.
Publication year - 2015
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.25631
Subject(s) - zymomonas mobilis , pentose , xylose , fermentation , pentose phosphate pathway , biochemistry , arabinose , xylose metabolism , transketolase , biology , chemistry , ethanol fuel , enzyme , glycolysis
ABSTRACT Zymomonas mobilis is capable of producing ethanol at high rates and titers from glucose. This bacterium has previously been engineered to consume the pentose sugars xylose and arabinose, but the rate of consumption of these sugars is low. Recent research has utilized adaptive evolution to isolate strains of Z. mobilis capable of rapidly fermenting xylose. In this study, we also used adaptive evolution to isolate strains of Z. mobilis capable of rapidly fermenting xylose and arabinose. To determine the bottlenecks in pentose metabolism, we then used high‐throughput sequencing to pinpoint the genetic changes responsible for the phenotypes of the adapted strains. We found that the transport of both xylose and arabinose through the native sugar transporter, Glf, limits pentose fermentations in Z. mobilis . We also found that mutations in the AddB protein increase plasmid stability and can reduce cellular aggregation in these strains. Consistent with previous research, we found that reduced xylitol production improves xylose fermentations in Z. mobilis . We also found that increased transketolase activity and reduced glyceraldehyde‐3‐phosphate dehydrogenase activity improve arabinose fermentations in Z. mobilis . Biotechnol. Bioeng. 2015;112: 2228–2240. © 2015 Wiley Periodicals, Inc.