自然发酵甘薯酸浆中乳酸菌的筛选与鉴定

Screening and Preliminary Identification of Lactic Acid Bacteria from Ipomoea batatas Acid Liquor during Natural Fermentation

[目的]从天然乳酸菌菌株中筛选出对甘薯淀粉分离起主要作用的菌种。[方法]利用MRS培养基从自然发酵的甘薯酸浆中分离出13株乳酸菌菌株,通过发酵试验筛选出1株分离效果良好的乳酸菌菌株,并对其进行初步鉴定。[结果]根据菌落形态、个体形态及生理生化反应结果,初步鉴定筛选出的沉淀淀粉能力较好的菌株为乳杆菌,表明乳杆菌菌体本身或由其产生的代谢产物对淀粉具有絮凝作用。从发酵液的乳酸菌总数、pH值来看,乳酸菌总数偏高的发酵液,pH值一般较低,分离效果也较好,表明分离效果与乳酸菌总数及酸浆的pH值有关。[结论]该研究为实现甘薯酸浆的人工发酵生产奠定了基础。

[ Objective] The aim was to screen the strain that played an important role in the separation of Ipomoea batatas starch from the natural lactic acid bacteria strains. [Method] 13 lactic acid bacteria strains were separated from 1. batatas acid liquor during natural fermentation with MRS medium. A strain of laetic acid bacteria with good separation effect was screened by the fermentation test and identified preliminarily. [ Result] The screened strain with better starch precipitating ability was identified preliminarily as lactobacillus according to the results of the colony morphology, the individual morphology and the physiological and biochemical responses, which showed that lactobacillus itself or its metaholites had flecculation on starch. From the total number of lactic acid bacteria in the fermentation broth and the pH value, the pH value of the fermentation broth with higher total number of lactic acid bacteria was usually lower and its sepaiation effect was better, which showed that the separation effect had relationship with the total number of lactic acid bacteria and the pH value of the acid liquor. [Conclusion] The research laid the foundation for the realization of the artificial fermentation production of 1. batatas acid liquor.