【摘要】 本文报导了L-乳酸产生菌筛选、发酵条件以及发酵产物鉴定的结果。从56株根霉中筛选出10株产L-乳酸较高的菌株,其中根霉R47产L-乳酸最高,产酸稳定。发酵条件试验结果表明,该菌最适发酵培养基组成（%）:葡萄糖15,尿素0.2,KH₂PO₄ 0.02,MgSO₄·7H₂O 0.025,ZnSO₄·7H₂O 0.0044,CaCO₃ 6,7;pH6.7。在摇瓶培养条件下,35℃48小时,产L-乳酸达11.84g/100ml,对糖的重量转化率达78.9%。发酵液经离子交换等方法纯化,得到无色或微黄色透明糖浆状液体。经纸层析、比旋光度测定、紫外光谱和红外光谱分析证明确系L-乳酸。更多还原

【Abstract】 Ten strains with higher capacity of Llactic acid production were screened from 56 strains belonging to the genus Rhizopus. Among these, strain R47 showed the highest yield of L-lactic acid, and the yield was stable. According to the experimental results of fermentation condition, the optimum medium for its fermentation consists of 15% glucose, 0.2% urea, 0.02% KH₂PO₄, 0.025% MgSO₄·7 H₂O, 0.0044% ZnSO₄·7H₂O, 6.7% CaCO₃, and pH 6.7. In shake flask culture, L-lactic acid yields was 11.84g/100ml at 35℃ for 48h, and weight conversion rate of glucose was 78.9%.The product isolated and purified from fermentative broth was a clear, colourless or light yellow syrop. It was identified as L-lactic acid by paper chromatography, specific rotation, ultravioler absorption spectrum and infrared absorption spectrum.更多还原