Isolation and Identification of Lactic Acid Bacteria from Rumen of Camel and Its Function in Degradation of Indole

Lactic acid bacteria(LAB)was isolated and screened from the rumen contents of camels,and its degradation functions on indole were studied in vitro. LAB in the rumen of camel were screened out in MRS medium,bacterial DNA was extracted,16S rDNA sequence was amplified,and phylogenetic tree was constructed. LAB were cultured under stress in inorganic salt medium with indole(500 mg/L)as the sole carbon and nitrogen source. The absorbance was measured by UV spectrophotometer(600 nm)to determine the growth cruve of lactic acid bacteria in the environment of high concentration indole. Indole residue was determined by GC-MS to measure the LAB’s ability of indole-degrading. The results showed that the four strains were all LAB,GU366019,GU366027,GU366021 and GU366034 belonged to Lactobacillus,among which GU366019,GU366027,GU366021 were Lactobacillus delbrueckii subsp.. GU366034 was Lactobacillus equicursoris. The four strains grew slowly in the indole-added inorganic salt medium,but had a strong ability to degrade indole. The indole could be completely degraded by GU366027,GU366019 and GU366021 in 144 h,and GU366034 in 156 h,with a degradation rate of 100%. It was proved that the LAB from camel rumen could degrade indole,and it could not only supply the microbial resources of intestinal toxin degradation,but also provide the research basis for LAB to degrade and remove intestinal toxin.