4株聚丙烯酰胺降解菌的深度驯化及联合降解作用

Gradient domestication and combined degradation of four polyacrylamide degrading bactria strains

从含聚污泥中分离出4株聚丙烯酰胺降解菌,分别命名为PM1、PM2、PM3和PM4,经16S r DNA鉴定,4种菌分别属于肠杆菌(Enterobacteriaceae bacterium),阴沟肠杆菌(Enterobacter cloacae),巨大芽孢杆菌(Bacillus megaterium)和霍米奇肠杆菌(Enterobacter hormaechei)。为了提高菌种对高浓度、高分子量含聚污水的适应能力及降解聚丙烯酰胺的效率,将其进行深度驯化并混合培养。结果表明:经过驯化,菌种的OD值明显高于驯化之前,4种降解菌对400 mg/L溶液中聚丙烯酰胺的降解率分别由驯化前的29.8%、30.9%、40.1%和33.4%提高到36%、40.1%、54.7%和42.7%;并且混合菌PM2&PM3在投加体积分数为4%时对聚丙烯酰胺降解率最高能达到67%,具有一定的协同作用。红外图谱结果显示,生物降解后聚丙烯酰胺分子结构发生变化,分子链上的酰胺基被氧化为羧基。

In this study,4 PAM-degrading bacterial strains,namely,PM1,PM2,PM3,and PM4,were isolated from activated sludge containing polyacrylamide. Analysis of 16 S r DNA sequence showed that these strains belonged to Enterobacteriaceae,Enterobacter cloacae,Bacillus megaterium,and Enterobacter hormaechei,respectively. PAM gradient domestication and mixed cultivation were performed to improve the polyacrylamide resistance and biodegradation efficiency of these strains. Our results showed that OD values of strains PM1,PM2,PM3,and PM4 after gradient domestication were significantly higher than those before gradient domestication and that the efficiency of these strains for degrading 400 mg / L PAM increased from 29. 8%,30. 9%,40. 1%,and33. 4%,respectively,to 36%,40. 1%,54. 7%,42. 7%,respectively. Further,the rate of 4% inocula（ volume ratio） of PM2 and PM3 for degrading 400 mg / L PAM was up to 67%,indicating a synergistic effect of the2 strains. Results of Fourier transform infrared spectroscopy indicated that biodegradation changed the molecular structure of PAM and converted the amide group of PAM to carboxyl group.