微生物发酵产光学纯度D-乳酸研究进展

D-乳酸作为一种重要的手性中间体和聚乳酸合成的原料,其生产已越来越受到人们的重视。然而,低光学纯度D-乳酸在很多领域的应用都受到限制。微生物发酵法能够生产高光学纯度的D-乳酸。除了乳酸生产的传统菌株-乳酸细菌,研究者们还通过基因工程的手段不断探索其它种属菌株利用更廉价的可再生资源高产光学纯度D-乳酸的可行性。介绍了D-乳酸的物化性质及其在工业生产、化学加工和聚乳酸合成中的应用,并详细综述了国内外发酵法生产光学纯度D-乳酸的最新研究进展,着重介绍了采用基因工程育种策略提高菌株的D-乳酸产量、转化率、生产强度以及光学纯度,降低副产物的合成,扩大底物利用范围的研究成果。所涉及的菌株包括:乳酸细菌、大肠杆菌、谷氨酸棒杆菌以及酵母等。这些研究表明,应用基因工程手段改造生产菌株的代谢途径是选育D-乳酸发酵生产菌株的发展趋势。最后还对D-乳酸发酵生产的前景进行了展望。

Advance in the Production of Optically Pure D-lactic Acid by Microbial Fermentation

D-lactic acid (D-lactate) is an important chiral intermediate and one raw material for PLA production. Due to the scarcity of petroleum resources and the improvement of environmental awareness, polylactic acid industry is rapidly expanding, which increases the demand for production of D-lactate. However, low optically pure D-lactate has limitations in many of its end uses. Microbial fermentation can produce high optically pure D-lactate. In resent years, quite a lot of research works have been done in this field. Properties of D-lactate and its applications in industrial production, chemical processing and PLA production are simply introduced. The main purpose here is to summarize the current situation of D-lactate producing strains, including lactic acid bacteria, Escherichia coli, Corynebacterium glutamicum and yeast, etc. Studies on these microorganisms indicated that the approach of metabolic engineering has been widely used to make D-lactate producing strains which have higher production level, yield, productivity and optical purity, lower by-product levels, and improved ability in utilizing more simplified, cheaper and easier available materials. Metabolic pathway reconstruction by metabolic engineering and genetic manipulation is a development trend of screening D-lactate producing strains. At last, some prospects about D-lactate fermentation were made.