大豆秸秆酶水解及L-乳酸发酵

ENZYMATIC HYDROLYSIS OF SOYBEAN STRAW ANDL-LACTIC ACID FERMENTATION

用纤维素酶对氨预处理后的大豆秸秆进行酶水解 ,利用纤维素酶的作用使纤维素、半纤维素水解为可溶性糖 ,继而研究了用干酪乳杆菌及清酒乳杆菌进行L 乳酸发酵 ,通过微生物发酵将生成的可溶性糖转化为用于生产具有可生物降解性的聚乳酸塑料的原料乳酸 ,实现可再生资源的充分利用 .结果表明 ,实验条件下 ,5 %的大豆秸秆经酶水解后 ,还原糖浓度为 2 4 2 2 5mg·g-1,纤维素糖化率为 5 1 2 2 % .清酒乳杆菌、干酪乳杆菌及该两种混合菌种发酵酶解液所得L 乳酸的转化率分别为 4 8 2 7%、 5 6 4 2 %和 71 0 5 % .

Soybean straw is an abundant, potential fermentation substrate. The most efficient means to produce fermentable sugars from soybean straw is enzymatic hydrolysis. For the sake of increasing the enzymatic hydrolysis of soybean straw and extracting the raw material for producing biodegradable plastic-lactic acid from soybean straw, enzymatic hydrolysis of soybean straw by cellulase was investigated. With initial soybean straw concentration of 5%, reducing sugar concentration and saccharification rate after enzymatic hydrolysis were 242.25 mg&middotg-1 and 51.22% respectively. L-lactic acid production by Lactobacillus casei and Lactobacillus sake on cellulose and hemicellulose hydrolysate of ammonia pretreated soybean straw was also studied. 7.52 g&middotL-1, 8.79 g&middotL-1 and 11.07 g&middotL-1 of lactic acid could be further obtained by fermentation with Lactobacillus casei and Lactobacillus sake and mix lactobacilluses. The lactic acid yields were 48.27%, 56.42% and 71.05% respectively based on glucose in hydrolysate.