骆驼瘤胃乳酸菌的分离、鉴定及其降解吲哚的功能研究

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

为研究从驼骆瘤胃内容物分离、筛选的乳酸菌,其体外降解吲哚的功能。利用MRS培养基筛选骆驼瘤胃乳酸菌,提取细菌总DNA,扩增16S rDNA序列,构建系统发育树。在以吲哚(500 mg/L)为唯一碳源、氮源的无机盐培养基中胁迫培养乳酸菌,紫外分光光度计测定吸光度值(600 nm),测定乳酸菌在高浓度吲哚环境中的生长曲线;使用GC-MS动态检测吲哚残留量,测定乳酸菌对吲哚的降解能力。结果显示:筛选获得4株乳酸菌,GU366019、GU366027、GU366021、GU366034均归属为乳杆菌属(Lactobacillus),其中GU366019、GU366027、GU366021为德氏乳杆菌亚种(Lactobacillus delbrueckii subsp.),GU366034为驯马乳杆菌(Lactobacillus equicursoris)。四株菌在添加吲哚的无机盐培养基中生长缓慢,但对吲哚降解能力强。GU366027、GU366019、GU366021在144 h内,GU366034在156 h可将吲哚100%降解,证实来源于骆驼瘤胃的乳酸菌具有降解吲哚的功能。本实验在补充肠道毒素降解微生物资源的同时,也为乳酸菌降解、清除肠道毒素提供了研究依据。

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,16 S 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.