四环素降解细菌菌群的富集驯化及特性研究

Enrichment,domestication and characterization oftetracycline-degrading bacteria communities

摘要:

为明晰四环素降解细菌菌群的生长特性及对盐酸四环素在不同培养条件下的降解效率,以猪粪为选菌材料,在基础无机盐培养基中(MM)加入初始浓度为50 mg/L的盐酸四环素依次富集驯化、传代培养直至盐酸四环素的浓度为300 mg/L,经过40代的富集培养,细菌群组成达到稳定,生长特性试验结果表明:细菌群落的最佳培养时间为30 h,此时D_{600 nm}值达到最大,为2.56;细菌群落生长的最适温度为30℃,此时D_{600 nm}值较20℃、25℃、35℃、40℃处理分别提高65%、19%、6%、51%,且各处理之间差异显著(P＜0.05);细菌群落在不同的pH梯度(6、7、8、9)下各处理之间差异显著(P＜0.05),最适宜pH为7,较pH为8和9时 D_{600 nm}值分别提高5%和12%,pH为6时明显抑制菌群的繁殖。降解特性测定结果发现,细菌群落在30℃、初始pH为7、培养7 d时接种量(1%、2%、3%)对降解特性的影响差异不显著(P＞0.05),碳源的添加会降低菌群对四环素的降解能力。

Abstract:

The growth characteristics and degradation efficiency of tetracycline degrading bacteria communities under different culture conditions were studied.The candidate material (pig manure) samples were placed in tetracycline solution to screen the tetracycline degrading bacteria communities.The initial tetracycline concentration for isolation and enrichment was 50 mg/L and it was gradually increased to 300 mg/L in subculture.After 40 generations' acclimation,the composition of the bacterial community was stable.The result showed that the optimal culture time was 30 h,and the D_{600 nm} reached 2.56.The appropriate temperature for the growth was 30℃,and the D_{600 nm} was 65%,19%,6% and 51% higher than the treatments at 20℃,25℃,35℃ and 40℃,respectively.The growth was also affected by pH value of solution.The most suitable pH was 7,in which,D_{600 nm} was 5% and 12% higher than pH 8 and 9.However,the reproduction of bacterial community was inhibited when pH was 6.There was no significant difference in the effect of inoculum amount (1%,2%,3%) on the degradation characteristics at 30℃,pH 7 for 7 days.The addition of carbon source decreased the degradation rate.