AUTHOR=Liu Yidong , Wang Xiuqing , Ma Liting , Lü Min , Zhang Wen , Lü Chuanjuan , Gao Chao , Xu Ping , Ma Cuiqing 

TITLE=Dehydrogenation Mechanism of Three Stereoisomers of Butane-2,3-Diol in Pseudomonas putida KT2440

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2021.728767

DOI=10.3389/fbioe.2021.728767

ISSN=2296-4185

ABSTRACT=<p><italic>Pseudomonas putida</italic> KT2440 is a promising chassis of industrial biotechnology due to its metabolic versatility. Butane-2,3-diol (2,3-BDO) is a precursor of numerous value-added chemicals. It is also a microbial metabolite which widely exists in various habiting environments of <italic>P. putida</italic> KT2440. It was reported that <italic>P. putida</italic> KT2440 is able to use 2,3-BDO as a sole carbon source for growth. There are three stereoisomeric forms of 2,3-BDO: (2<italic>R</italic>,3<italic>R</italic>)-2,3-BDO, <italic>meso</italic>-2,3-BDO and (2<italic>S</italic>,3<italic>S</italic>)-2,3-BDO. However, whether <italic>P. putida</italic> KT2440 can utilize three stereoisomeric forms of 2,3-BDO has not been elucidated. Here, we revealed the genomic and enzymic basis of <italic>P. putida</italic> KT2440 for dehydrogenation of different stereoisomers of 2,3-BDO into acetoin, which will be channeled to central mechanism via acetoin dehydrogenase enzyme system. (2<italic>R</italic>,3<italic>R</italic>)-2,3-BDO dehydrogenase (PP0552) was detailedly characterized and identified to participate in (2<italic>R</italic>,3<italic>R</italic>)-2,3-BDO and <italic>meso</italic>-2,3-BDO dehydrogenation. Two quinoprotein alcohol dehydrogenases, PedE (PP2674) and PedH (PP2679), were confirmed to be responsible for (2<italic>S</italic>,3<italic>S</italic>)-2,3-BDO dehydrogenation. The function redundancy and inverse regulation of PedH and PedE by lanthanide availability provides a mechanism for the adaption of <italic>P. putida</italic> KT2440 to variable environmental conditions. Elucidation of the mechanism of 2,3-BDO catabolism in <italic>P. putida</italic> KT2440 would provide new insights for bioproduction of 2,3-BDO-derived chemicals based on this robust chassis.</p>