固定化乳酸杆菌发酵纤维素水解液的研究

LACTIC ACID FERMENTATION BY IMMOBILIZED LACTOBACILLUS DELBRUECKII CELLS USING CELLULOSIC HYDROLYSATE

采用海藻酸钙凝胶包埋法固定德氏乳酸杆菌,固定化细胞可有效地利用纤维素水解液发酵生产乳酸。与游离细胞相比,固定化细胞具有发酵时间短、乳酸得率高等优点,其最适发酵温度为48℃,添加适量的麸皮水解液对乳酸发酵有明显的促进作用,乳酸得率可达90.1%。利用固定化细胞重复分批发酵纤维素水解液生产乳酸,连续16批发酵试验表明,固定化细胞性状稳定,产酸能力强,乳酸平均得率为88.6%。利用固定化细胞在柱式反应器中连续发酵纤维素水解液,当稀释率为0.12h-1时,乳酸得率和生产效率分别达到80.2%和4.97g/(L·h)。

Cellulosic material is the most abundant renewable carbon source in the world.Using cellulosic hydrolysate instead of starch for lactic acid production is meaningful.Lactobacillus delbrueckii cells were immobilized by (entrapped) into calcium alginate gels.The immobilized cells were quite stable,and could utilize cellulosic hydrolysate to produce lactic acid efficiently.Optimum fermentation temperature was 48 ℃,and wheat bran hydrolysate could promote the production of lactic acid obviously.Comparing with free cells,the fermentation term of immobilized cells was (shortened),and the yield of lactic acid could reach 90.1% on cellulosic hydrolysate from corn cob.During 16 repeated batch fermentation processes,average yield of lactic acid was 88.6% using the immobilized cells on cellulosic (hydrolysate).Continuous fermentation process was carried out in a 250 mL column reactor with immobilized cells on cellulosic hydrolysate,the lactic acid yield and production efficiency under 0.12 h^(-1) dilution rate were 80.2% and (4.97 g/(L·h)),respectively.