Enhanced L-(+)-lactic acid production by an adapted strain of Rhizopus oryzae using corncob hydrolysate
Enhanced L-(+)-lactic acid production by an adapted strain of Rhizopus oryzae using corncob hydrolysate
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DOI：
10.1007/s12010-007-8078-y
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发表时间：
2008-01-01
影响因子：
3
通讯作者：
Cui, Zhan-Feng
中科院分区：
文献类型：
--
作者：
Bai, Dong-Mei;Li, Shi-Zhong;Cui, Zhan-Feng
玉米芯是一种经济原料，中国每年生产的玉米芯超过2000万吨。大量的木糖可以从玉米芯中大量的半纤维素材料中转化，这使得作物秸秆成为多种生物产品增值生产的有吸引力的替代基质。乳酸可用作生产聚乳酸的前驱体。虽然目前的工业乳酸是由乳酸菌利用富集培养基生产的，但米根霉的生产是首选的，因为它具有独特的异构体形成和真菌对营养的简单需求。米曲霉利用木糖生产l -(+)-乳酸已有报道；但与使用葡萄糖相比，其产率和转化率较差。在本研究中，我们报道了一株适应型稻瘟病菌HZS6，该菌株显著提高了底物利用率，并提高了玉米芯水解物中L-(+)-乳酸的产量。L-(+)-乳酸终浓度、产量和体积生产力均比亲本菌株提高2倍以上。确定了菌株HZS6的最佳生长和发酵条件。
Corncob is an economic feedstock and more than 20 million tons of corncobs are produced annually in China. Abundant xylose can be potentially converted from the large amount of hemicellulosic materials in corncobs, which makes the crop residue an attractive alternative substrate for a value-added production of a variety of bioproducts. Lactic acid can be used as a precursor for poly-lactic acid production. Although current industrial lactic acid is produced by lactic acid bacteria using enriched medium, production by Rhizopus oryzae is preferred due to its exclusive formation of the-isomer and a simple nutrition requirement by the fungus. Production of-L-(+)-lactic acid by R. oryzae using xylose has been reported; however, its yield and conversion rate are poor compared with that of using glucose. In this study, we report an adapted R. oryzae strain HZS6 that significantly improved efficiency of substrate utilization and enhanced production of L-(+)-lactic acid from corncob hydrolysate. It increased L-(+)-lactic acid final concentration, yield, and volumetric productivity more than twofold compared with its parental strain. The optimized growth and fermentation conditions for Strain HZS6 were defined.