对虾养殖环境中乳酸菌的筛选及其发酵工艺的研究

Screening of Lactic Acid Bacteria in Shrimp Culture Environment and Study on Its Fermentation Technology

[目的]对虾养殖环境中乳酸菌进行筛选并对其发酵工艺进行研究。[方法]首先利用含碳酸钙的MRS固体培养基从虾养殖环境中的海水和底泥中筛选出有溶钙圈的菌株M5;接着根据16S r DNA基因序列系统发育树分析对菌株M5进行鉴定,最后在单因子实验的基础上,通过正交试验对发酵工艺进行优化。[结果]初步鉴定菌株M5为粪肠球菌,该菌株的最佳发酵工艺为:甘蔗糖蜜浓度为5%,蛋白胨浓度为0.75%,硫酸铵0.5%,磷酸氢二钾的浓度为0.5%,发酵温度为30℃,发酵时间为48 h。在以上工艺下,发酵液中乳酸菌的活菌数高达4.97×108CFU/m L。[结论]本研究对对虾养殖所用乳酸菌的发酵生产具有一定的参考价值。

[Objective]Lactic Acid Bacteria(LAB)were screened in shrimp culture environment and study on its fermentation technology.[Method]Firstly,strain M5 with calcium dissolving ring was screened out from seawater and sediment in shrimp culture environment using MRS solid medium containing calcium carbonate.Secondly,identification of strain M5 based on phylogenetic tree analysis of 16S rDNA gene sequence.Finally,the fermentation technology was optimized by orthogonal experiments on the basis of single factor experiments.[Result]The strain M5 was preliminarily identified as Enterococcus faecalis.The optimum fermentation conditions of the strain were as follow:sugarcane molasses 5%,peptone 0.75%,ammonium sulfate 0.5%,dipotassium hydrogenphosphate concentration 0.5%,fermentation temperature 30℃and fermentation time 48 H.Under the above conditions,the number of LAB in the fermentation broth was as high as 4.97×10^8 CFU/mL.[Conclusion]The study has certain reference value for the fermentation production of LAB used in shrimp culture.