乳酸菌利用罗非鱼下脚料水解液发酵L-乳酸的探讨

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 thermophi-lus）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。

Research on L-lactic acid fermentation for hydrolysate of tilapia wastes with Lactobacillus

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.