Elucidating the contributions of multiple aldehyde/alcohol dehydrogenases to butanol and ethanol production in Clostridium acetobutylicum.
Ethanol and butanol biosynthesis in Clostridium acetobutylicum share common aldehyde/alcohol dehydrogenases. However, little is known about the relative contributions of these multiple dehydrogenases to ethanol and butanol production respectively. The contributions of six aldehyde/alcohol dehydrogenases of C. acetobutylicum on butanol and ethanol production were evaluated through inactivation of the corresponding genes respectively. For butanol production, the relative contributions from these enzymes were: AdhE1 > BdhB > BdhA ≈ YqhD > SMB_P058 > AdhE2. For ethanol production, the contributions were: AdhE1 > BdhB > YqhD > SMB_P058 > AdhE2 > BdhA. AdhE1 and BdhB are two essential enzymes for butanol and ethanol production. AdhE1 was relatively specific for butanol production over ethanol, while BdhB, YqhD, and SMB_P058 favor ethanol production over butanol. Butanol synthesis was increased in the adhE2 mutant, which had a higher butanol/ethanol ratio (8.15:1) compared with wild type strain (6.65:1). Both the SMB_P058 mutant and yqhD mutant produced less ethanol without loss of butanol formation, which led to higher butanol/ethanol ratio, 10.12:1 and 10.17:1, respectively. To engineer a more efficient butanol-producing strain, adhE1 could be overexpressed, furthermore, adhE2, SMB_P058, yqhD are promising gene inactivation targets. This work provides useful information guiding future strain improvement for butanol production.
CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.|Department of Biochemistry and Molecular Biology, University of Science and Technology of China, Hefei, 230026, China.
Zongjie
Z
Dai
CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
Hongjun
H
Dong
CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
Yanping
Y
Zhang
CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
Yin
Y
Li
D000426:Alcohol Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D056804:Biofuels / Q000382:microbiology; D019149:Bioreactors / Q000382:microbiology*; D000440:Butanols / Q000378:metabolism*; D046969:Clostridium acetobutylicum / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation / Q000235:genetics* / Q000502:physiology; D010084:Oxidation-Reduction
D056804:Biofuels; D000440:Butanols; D004269:DNA, Bacterial; D000431:Ethanol; D000426:Alcohol Dehydrogenase; D000444:Aldehyde Dehydrogenase