Microbial reduction using ethanol as an energy source

前手性酮的微生物还原是制备手性仲醇的一种有效方法。最近，开发了一种以乙醇代替糖作为能量来源的面包师酵母介导生物还原的新程序。本研究旨在研究以乙醇为能源的微生物还原性，并研究其培养条件与还原性的关系。利用乙醇作为NAD(P)H再生和生物还原的能量来源的微生物筛选许多被测试的菌株使用乙醇和/或乙酸作为NAD(P)H再生和生物还原的能量来源，其方式与葡萄糖相同。然后，霉菌只使用葡萄糖作为能量来源，而不使用乙醇或醋酸盐。另一方面，一些细菌有效地利用乙醇而不是葡萄糖。研究了酵母细胞内乙醇氧化途径氧化NAD(P)H的再生方案。结果表明，NADH通过酒精氧化再生为乙酸，NADPH通过乙酸氧化再生为二氧化碳。以乙醇为能源再生NAD(P)H的能力与培养条件对吸氧速率的关系在厌氧条件下培养的酵母Saccharomysex cerevisiae HUT 7099以乙醇为能量源再生NAD(P)H的能力较低。其原因与醛脱氢酶活性降低有关，而醇脱氢酶活性不受该培养条件的影响。

The microbial reduction of prochiral ketones has been recognaized as a useful technique to prepare a chiral secondary alcohols. Recently, a new procedure for the baker's yeast-mediated bioreduction using ethanol instead of sugar as the energy source was developed. This research is to study the microbial reduction using ethanol as the energy source and to study the relation between culitivation conditions and the reduction ability.1.Screening of microbials using ethanol as an energy source for NAD(P)H regneration coupled with a bioreductionMany of the tested strains of years use ethanol and/or acetate as an energy source for NAD(P)H regneration coupled with a bioreduction in the same manner as glucose. Then, molds use only glucose as the energy source but ethanol or acetate. On the other hand, some of bacterias use ethanol effectively but glucose.A scheme for NAD(P)H regeneration from the corresponding oxidezed from through the oxidative pathway of ethanol in yeast cells was studied. THe results suggested tha NADH was regenerated through alcoholic oxidation into acetate and NADPH through acetate oxidation into carbon cioxide.2.Relationship between the ability using ethanol as energy sourcet for NAD(P)H regeneration and the culture condition on oxygen absorption rate.Yeasts, Saccharomysex cerevisiae HUT 7099, cultured under more anaerobic conditions had the lower ablity using ethanol as energy source for NAD(P)H regeneration. The reason was related to lower activity of aldehyde dehydrogenase though the activity of alcohol dehydrogenase was not influensed by such culture conditions.