同化和共代谢降解氯苯菌株的筛选与特性研究

基于污染场地，筛选了一株可降解氯苯（CB）的微生物，经鉴定该菌株属于粘质沙雷氏菌属（Serratia marcescans），命名为Serratia marcescans TF-1.同化降解结果表明，该菌株能够在有氧的条件下以CB为唯一碳源和能源，菌体平均增长速率为0.0063~0.022g_cell/（mol_CB·h），最大比生长速率（μ_max）为0.015~0.42h^-1，CB降解速率（V_CB）为1.35~4.47mol/（g_cell·h），菌株对CB最高耐受浓度高于200mg/L.共代谢降解结果显示，TF-1可以琥珀酸钠和柠檬酸钠为底物共代谢降解CB；氯苯浓度（c_CB）<80mg/L时，μ_{max（柠檬酸钠）}（0.21~0.87h^-1）>μ_{max（琥珀酸钠）}（0.20~0.81h^-1），V_{CB（柠檬酸钠）}（0.15~0.47mol/（g_cell·h））<V_{CB（琥珀酸钠）}（0.17~0.48mol/（g_cell·h））；c_CB>80mg/L时，μ_{max（柠檬酸钠）}（0.086~0.21h^-1）<μ_{max（琥珀酸钠）}（0.17~0.25h^-1），V_{CB（柠檬酸钠）}（0.61~1.11mol/（g_cell·h））>V_{CB（琥珀酸钠）}（0.56~0.95mol/（g_cell·h）），表明共代谢降解过程中，CB浓度，底物种类是调控污染降解的重要因素.最后考察了温度、pH值和接种量对TF-1降解CB的影响，结果发现，该菌株适宜生长的温度范围为20~35℃，最适温度为30℃；适宜生长pH值为5~9，最适pH值为7；最适接种量为5%.与现有菌株比较发现TF-1的温度和pH值适用范围更广，降解能力更强，污染物耐受浓度更高，既能同化又能共代谢降解CB，在贫营养和富营养污染场地中应用潜力更大.本研究可为原位CB污染场地修复提供有效的生物资源.

Screening and characterization of an assimilation and co-metabolism-degrading chlorobenzene bacterial strain

In this study, a novel chlorobenzene (CB)-degrading strain was isolated on the contaminated site and identified as Serratia marcescans TF-1. The assimilation degradation analysis showed that CB can be used by strain TF-1as the sole carbon source and energy under aerobic conditions, and the corresponding average growth rate, the maximum specific growth rate (μ_max), the CB degradation rate, and the maximum CB tolerance concentration were 0.0063~0.022g_cell/(mol_CB·h), 0.015~0.42h^-1, 1.35~4.47mol/(g_cell·h), 200mg/L, respectively. Moreover, sodium succinate and sodium citrate can be co-metabolized by strain TF-1as substrates. μ_max (sodium citrate), μ_max (sodium succinate), V_CB(sodium citrate) and V_CB(sodium succinate) were 0.21~0.87h^?1, 0.20~0.81h^?1, 0.15~0.47mol/(g_cell·h) and 0.17~0.48mol/(g_cell·h) respectively, when CB concentration was less than 80mg/L, and μ_max (sodium citrate), μ_max (sodium succinate), V_CB(sodium citrate) and V_CB(sodium succinate) were 0.086~0.21h^?1, 0.17~0.25h^?1, 0.61~1.11mol/(g_cell·h) and 0.56~0.95mol/(g_cell·h) respectively, when CB concentration was greater than 80mg/L. The results showed that the substrate type is the key factor in the co-metabolic degradation. Finally, the effects of temperature, pH and inoculation concentration on the degradation of CB by TF-1 were investigated. The results showed that the growth temperature and pH range of TF-1 were 20~35℃ and 5~9, respectively. The optimal growth temperature of 30℃, pH of 7 and inoculation concentration of 5% were also obtained. The results indicated that TF-1 had a wider temperature and pH application range, stronger degradation ability, and higher tolerance to pollutant concentration. In addition, CB could be used directly or co-metabolized by strain TF-1, which was suitable for application in oligotrophic and eutrophic contaminated sites. This study provided effective biological resources for in-situ CB contaminated site remediation.