Hydrogen-driven asymmetric reduction of hydroxyacetone to (R)-1,2-propanediol by Ralstonia eutropha transformant expressing alcohol dehydrogenase from Kluyveromyces lactis

Microbial Cell Factories

Research

Koji Oda¹  Hirofumi Nishihara¹  Takahiro Oda¹  Masaharu Ishii²  Yasuo Igarashi²  Akinobu Matsuyama³  Hiroaki Yamamoto³ 

[1] Department of Bioresource Science, College of Agriculture, Ibaraki University, 3-21-1 Chu-ou, Ami-machi, Inashiki-gun, 300-0393, Ibaraki, Japan;Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, 113-8657, Tokyo, Japan;Green Product Development Center, R&D Management, Daicel Corporation, 1-1 Shinko-cho, 944-8550, Myoko, Niigata, Japan;

关键词: Hydrogen-driven bioconversion;    Hydrogen-driven cell factory;    NAD-reducing soluble hydrogenase;    Alcohol dehydrogenase;    Cofactor regeneration;    R;    Hydrogen-oxidizing bacterium;    Ralstonia eutropha;   

DOI  :  10.1186/1475-2859-12-2

 received in 2012-08-24, accepted in 2013-01-06,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundConversion of industrial processes to more nature-friendly modes is a crucial subject for achieving sustainable development. Utilization of hydrogen-oxidation reactions by hydrogenase as a driving force of bioprocess reaction can be an environmentally ideal method because the reaction creates no pollutants. We expressed NAD-dependent alcohol dehydrogenase from Kluyveromyces lactis in a hydrogen-oxidizing bacterium: Ralstonia eutropha. This is the first report of hydrogen-driven in vivo coupling reaction of the alcohol dehydrogenase and indigenous soluble NAD-reducing hydrogenase. Asymmetric reduction of hydroxyacetone to (R)-1,2-propanediol, which is a commercial building block for antibacterial agents, was performed using the transformant as the microbial cell catalyst.ResultsThe two enzymes coupled in vitro in vials without a marked decrease of reactivity during the 20 hr reaction because of the hydrogenase reaction, which generates no by-product that affects enzymes. Alcohol dehydrogenase was expressed functionally in R. eutropha in an activity level equivalent to that of indigenous NAD-reducing hydrogenase under the hydrogenase promoter. The hydrogen-driven in vivo coupling reaction proceeded only by the transformant cell without exogenous addition of a cofactor. The decrease of reaction velocity at higher concentration of hydroxyacetone was markedly reduced by application of an in vivo coupling system. Production of (R)-1,2-propanediol (99.8% e.e.) reached 67.7 g/l in 76 hr with almost a constant rate using a jar fermenter. The reaction velocity under 10% PH2 was almost equivalent to that under 100% hydrogen, indicating the availability of crude hydrogen gas from various sources. The in vivo coupling system enabled cell-recycling as catalysts.ConclusionsAsymmetric reduction of hydroxyacetone by a coupling reaction of the two enzymes continued in both in vitro and in vivo systems in the presence of hydrogen. The in vivo reaction system using R. eutropha transformant expressing heterologous alcohol dehydrogenase showed advantages for practical usage relative to the in vitro coupling system. The results suggest a hopeful perspective of the hydrogen-driven bioprocess as an environmentally outstanding method to achieve industrial green innovation. Hydrogen-oxidizing bacteria can be useful hosts for the development of hydrogen-driven microbial cell factories.

【 授权许可】

Unknown   
© Oda et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.