腐败苹果中乳酸球菌的分离与鉴定

Isolation and Identification of a Strain of Lactococcus lactis from Rotten Apple

乳酸菌是健康人和动物肠道的优势菌群之一,对于维持肠道微环境的稳定与健康发挥着重要的作用。开发和利用乳酸菌资源,并对其进行分离鉴定和生物学特性研究,对推动乳酸菌的基础研究、开发具有应用特色的乳酸菌制品具有重要意义。本文利用MRS培养基(乳酸菌分离专用培养基)从腐败的苹果中分离得到乳酸菌,运用传统分离鉴定方法对其进行了形态观察、硝酸盐还原试验、葡萄糖产气试验、6.5%氯化钠耐盐性试验等,该菌株被鉴定为乳球菌属,并通过测定该菌株的生长曲线和产酸量研究其生长状况和产酸能力。结果表明,该菌株在培养32 h时处于对数生长期,在32~38 h趋于稳定,在培养38 h后开始衰减。产酸量在培养36 h时达到最高,为34°T,之后趋于稳定,在38 h后产酸量开始下降。

Lactic acid bacteria are one of the dominant intestinal microflora in healthy humans and animals,and play an important role in maintaining the stability and health of the intestinal microenvironment.The development and utilization of lactic acid bacteria resources,as well as the isolation and identification of them and the study of their biological characteristics,are of great significance for promoting basic research on lactic acid bacteria and developing lactic acid bacteria products with application characteristics.In this paper,a strain of lactic acid bacteria was isolated from the rotten apple by MRS culture medium.The strain was identified by using the morphological observation,nitrate reduction test,the test of gas production of glucose and 6.5%NaCl salt tolerance test.Its growth curve and acid production ability of the strain was measured. The results showed that the strain was in logarithmic growth phase after 32 h culture, in stabilized phase after 32-38 h culture, beginning to decline after 38 h culture. Acid production reached the highest at 34 °T after 36 h, then stabilized, and began to decline after 38 h.