Evolution of D-lactate dehydrogenase activity from glycerol dehydrogenase and its utility for D-lactate production from lignocellulose
Evolution of D-lactate dehydrogenase activity from glycerol dehydrogenase and its utility for D-lactate production from lignocellulose
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DOI：
10.1073/pnas.1111085108
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发表时间：
2011-11-22
影响因子：
11.1
通讯作者：
Shanmugam, K. T.
中科院分区：
文献类型：
--
作者：
Wang, Qingzhao;Ingram, Lonnie O.;Shanmugam, K. T.
乳酸是一种用于生产生物基塑料（聚乳酸，PLA）的有吸引力的可再生化学品，目前商业上从基于食品的糖来源生产。PLA所需的乳酸盐的纯光学异构体通常通过糖在低于40 ° C的温度下的微生物发酵来产生。凝结芽孢杆菌产生L（+）-乳酸作为初级发酵产物，并且在50 ° C和pH 5下生长最佳，这是商业真菌纤维素酶活性的最佳条件。通过删除天然ldh（L-乳酸脱氢酶）和alsS（乙酰乳酸合酶）基因以阻止厌氧生长，然后通过基于生长的选择以分离恢复生长的抑制突变体，将该菌株工程化以产生D（-）-乳酸。其中一株菌株QZ 19，在100 ℃下从葡萄糖产生约90 g L-1的光学纯D（-）-乳酸，
Lactic acid, an attractive, renewable chemical for production of biobased plastics (polylactic acid, PLA), is currently commercially produced from food-based sources of sugar. Pure optical isomers of lactate needed for PLA are typically produced by microbial fermentation of sugars at temperatures below 40 degrees C. Bacillus coagulans produces L(+)-lactate as a primary fermentation product and grows optimally at 50 degrees C and pH 5, conditions that are optimal for activity of commercial fungal cellulases. This strain was engineered to produce D(-)-lactate by deleting the native ldh (L-lactate dehydrogenase) and alsS (acetolactate synthase) genes to impede anaerobic growth, followed by growth-based selection to isolate suppressor mutants that restored growth. One of these, strain QZ19, produced about 90 g L-1 of optically pure D(-)-lactic acid from glucose in