小鼠胃肠道中乙醛降解菌的分离·鉴定及乙醛降解特性的测定

Isolation and Identification of Acetaldehyde-degrading Bacteria from the Gastrointestinal Tract of Mice and Determination of Their Acetaldehyde Degradation Characteristics

[目的]从小鼠胃肠道分离并鉴定乙醛降解菌,测定其乙醛降解率。[方法]以C57小鼠为实验动物,分别采集小鼠胃、小肠及结肠内容物,分离可培养的菌株,然后在培养基中加入乙醛,筛选乙醛耐受菌并测定其乙醛耐受能力,采用间苯二酚法测定乙醛降解能力,最后通过16S r RNA测序鉴定乙醛降解菌。[结果]从小鼠胃、小肠及结肠中分别筛选出一株能够降解乙醛的菌株,分别命名为TXZ-1、TXZ-2、TXZ-3。鉴定结果显示,这3株菌都属于粪肠球菌(Enterococcus faecalis),相似度达到99%,这些菌株的乙醛耐受能力和降解能力各不相同,其中TXZ-3的耐受和降解能力最强,耐受能力达到1.6 g/L。乙醛的最适降解条件为:接种量2.0%,乙醛浓度1.0 g/L,培养温度35℃,pH 7.0,摇床转速160 r/min,培养时间24 h,乙醛降解率达到(93.6±4.9)%。[结论]从小鼠胃肠道中筛选出高效快速降解乙醛的菌株TXZ-3,为研究乙醛污染的生物治理及人体中乙醛的清除提供了新思路。

[ Objective] The study aimed to isolate and identity acetaldehyde-degrading bacteria from gastrointestinal tract of mice and determine their acetaldehyde degradation rates. [ Method ] Taking C57 mice as experimental animal, the contents of mouse stomach, small intestine and colon were collected to isolate bacterial strains. Then acetaldehyde was added in the medium to screen acetaldehyde-tolerant bacteria and determine their acetaldehyde-tolerant ability. Resorcinol method was used to determine acetaldehyde degradation ability. Finally, 16S rRNA sequencing was used to identity acetaldehyde-degrading bacteria. [ Result ] Acetaldehyde-degrading baeteria strains were sereened from mouse stomach, small intestine and eolon, named as TSZ-1,-TXZ-2, TXZ-3, respectively. The identification results showed that the three strains belonged to Enterococcusfaecalis and the similarity reached 99%. The acetaldehyde tolerance and acetaldehyde degradation ability of these bacteria were different. Among them, TXZ-3 strain had the strongest tolerance and degradation ability, the tolerance reached 1.6 g/L. The optinmm degradation conditions for acetaldehyde were as follows： inoculation amount 2.0%, acetaldehyde concentration 1.0 g/L, incubation temperature 35℃, pH 7.0, rotating rate of 160 r/min. Aeetaldehyde degradation rate reaehed （93.6 ± 4.9）% after 24 h. [ Conclusion] TXZ-3 strain screened from the gastrointestinal tract of mice had the ability to degrade acetaldehyde efficiently and rapidly, which could provide new ideas tor biological treatment of acetaldehyde pollution and removal of acetaldehyde from human body.