Kataoka Naoya, Vangnai Alisa S, Pongtharangkul Thunyarat, Tajima Takahisa, Yakushi Toshiharu, Matsushita Kazunobu, Kato Junichi
Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan.
Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok 10330, Thailand.
J Biotechnol. 2015 Jun 20;204:25-32. doi: 10.1016/j.jbiotec.2015.03.027. Epub 2015 Apr 10.
1-Butanol is an important industrial platform chemical and an advanced biofuel. While various groups have attempted to construct synthetic pathways for 1-butanol production, efforts to construct a pathway that functions under aerobic conditions have met with limited success. Here, we constructed a CoA-dependent 1-butanol synthetic pathway that functions under aerobic conditions in Escherichia coli, by expanding the previously reported (R)-1,3-butanediol synthetic pathway. The pathway consists of phaA (acetyltransferase) and phaB (NADPH-dependent acetoacetyl-CoA reductase) from Ralstonia eutropha, phaJ ((R)-specific enoyl-CoA hydratase) from Aeromonas caviae, ter (trans-enoyl-CoA reductase) from Treponema denticola, bld (butylraldehyde dehydrogenase) from Clostridium saccharoperbutylacetonicum, and inherent alcohol dehydrogenase(s) from E. coli. To evaluate the potential of this pathway for 1-butanol production, culture conditions, including volumetric oxygen transfer coefficient (kLa) and pH were optimized in a mini-jar fermenter. Under optimal conditions, 1-butanol was produced at a concentration of up to 8.60gL(-1) after 46h of fed-batch cultivation.
1-丁醇是一种重要的工业平台化学品和先进生物燃料。尽管多个研究小组尝试构建用于生产1-丁醇的合成途径，但构建在有氧条件下发挥作用的途径的努力取得的成功有限。在此，我们通过扩展先前报道的（R）-1,3-丁二醇合成途径，构建了一种在有氧条件下于大肠杆菌中发挥作用的依赖辅酶A的1-丁醇合成途径。该途径由来自真养产碱菌的phaA（乙酰转移酶）和phaB（依赖NADPH的乙酰乙酰辅酶A还原酶）、来自豚鼠气单胞菌的phaJ（（R）-特异性烯酰辅酶A水合酶）、来自龋齿密螺旋体的ter（反式烯酰辅酶A还原酶）、来自产琥珀酸丁基丙酮梭菌的bld（丁醛脱氢酶）以及大肠杆菌固有的醇脱氢酶组成。为了评估该途径生产1-丁醇的潜力，在小型罐式发酵罐中对包括体积氧传递系数（kLa）和pH在内的培养条件进行了优化。在最佳条件下，补料分批培养46小时后，1-丁醇的产量高达8.60 gL⁻¹。
