乳酸菌利用罗非鱼下脚料水解液发酵L-乳酸的探讨

摘要

By hot water extraction method, we extracted the protein hydrolysate of tilapia wastes, which is used as a nitrogen source for L-lactic acid fermentation. Compared with yeast extract, we studied the growth of Lactobacillus bulgaricus, Streptococcus thermophilus and L rhamnosus in fermentation medium of hydrolysate of tilapia wastes, and observed the yield of L-lactic acid. Results show that the 3 lactic acid bacteria grow better in 2 fermentation mediums and pH decreases obviously. The production of L-lactic acid varies with different lactic acid bacteria. The net yield of L-lactic acid is 3. 38 g·L-1 after 10 h fermentation with L rhamnosus in the fermentation medium of hydrolysate of tilapia wastes. The yield is considerable to that of the yeast extract Therefore, the hydrolysate of tilapia wastes can be a substitute for yeast extract and is a low-cost nitrogen source for the yield of L-lactic acid.%以罗非鱼(Oreochromis spp.)下脚料为原料,采用高温热水抽提法提取其蛋白质作为乳酸菌发酵L-乳酸的氮源.以酵母膏作为对照,探讨了保加利亚乳杆菌(Lactobacillus bulgaricus)、嗜热链球菌(Streptococcus thermophilus)和鼠李糖乳杆菌(L.rhamnosus)在罗非鱼下脚料水解液培养基中的生长情况及L-乳酸的产量.结果显示,3种乳酸菌在2种培养基中均能良好地生长,pH下降明显；L-乳酸产量随乳酸菌菌种不同而异,其中鼠李糖乳杆菌在罗非鱼下脚料水解液培养基中发酵10 h后,L-乳酸净产量为3.38 g·L-1,与以酵母膏作为氮源的产酸水平相当.可见罗非鱼下脚料水解液可以替代酵母膏作为L-乳酸发酵的一种低成本氮源.