玉米生粉发酵生产L-乳酸的研究

研究了以α 淀粉酶为主的多种酶配合作用对玉米生粉乳酸发酵的影响。添加纤维素酶、酸性蛋白酶和脂肪酶能够加强液化酶和糖化酶对玉米生粉的水解作用 ,提高产酸水平和底物利用率。各种酶的最适添加量为α 淀粉酶 :8u/g干淀粉 ;纤维素酶 :5u/g原料 ;酸性蛋白酶 :2u/g原料 ;脂肪酶 :1u/g原料。在此条件下 ,当玉米粉初始浓度为 14 0g/L时 ,摇瓶产酸 6 5 .72 g/L ,发酵罐中产酸可达 71.6 5 g/L ,达到并超过高温蒸煮乳酸发酵的水平。同时研究了底物浓度对产酸的影响。

Study on L-Lactic Acid Production with Uncooked Raw Corn Flour Fermentation

The effects of α amylase, cellulase, pectinase and lipidase on L lactic acid production with uncooked corn flour fermentation were studied in detail. The results showed that cellulase and proteinase could markedly improve the L lactic acid fermentation of raw corn flour without cooking, shorten the period of fermentation, and lipidase also improved the L lactic acid fermentation. The optimal adding amount of enzymes were determined, that was α amylase 8u/g dry starch, cellulase 5u/g raw material, acidic proteinase 2u/g raw material, lipidase 1u/g raw material. When initial corn flour concentration is 140g/L, by adding enzyme described above, the L lactic acid concentration of fermentation broth in flask and stirred tank fermentor reached 65.72g/L and 71.65g/L , respectively, which reached or exceeded that of with cooked corn flour.