4株苯磺隆降解菌的分离鉴定及其生长特性

Isolation, Identification and Growth Characteristics of Four Tribenuron-methyl Degrading Bacterias

从长期受农药苯磺隆污染的土壤中通过采用富集培养分离技术得到4株以苯磺隆为唯一碳源生长的细菌,分别将其命名为B1、B2、B3和B4。通过观察这4种菌株的形态学特征,研究其生理生化特性以及分析其16S rDNA序列,初步鉴定菌株B1为铜绿假单胞菌（Pseudomonas aeruginosa）,B2为戴尔福特菌（Delftia sp.）,B3为微杆菌（Microbacterium sp.）,B4为产碱杆菌（Alcaligenes sp.）。并通过研究温度、初始pH值、接种量、苯磺隆初始浓度、培养基体积、氮源、碳源、Mg^2＋浓度等因素对4种菌株生长情况的影响,确定了菌株的最佳生长条件。结果显示,B1菌株的最适温度为35℃,其他3株菌株均为30℃。菌株B3最适pH为8.0,其余3株菌株均为pH7.0。B1和B3菌株最适接种量为15%,B2和B4最适接种量为10%。菌株B3最适苯磺隆初始浓度为100mg·L^-1,其余菌株最适苯磺隆初始浓度均为200mg·L^-1。4株菌株最适培养基体积均为75mL,最适氮源均为硝酸铵,最适碳源均为葡萄糖。B2菌株最适Mg^2＋浓度为100mg·L^-1,其余3株菌株均为200mg·L^-1。B1和B4菌株最适NaCl浓度为20g·L^-1,B2菌株NaCl浓度为5-30g·L^-1,B3菌株最适NaCl浓度为50g·L^-1。该结果为利用微生物对农药苯磺隆污染的土壤进行原位生物修复提供理论依据。

Four bacterias named B1, B2, B3 and B4 which were able to degrade tribenuron-methyl, were isolated from the soil of long term applied with tribenuron-methyl by enrichment culture. Based on physiological and biochemical characteristics and 16 S rDNA sequence analysis, the strain B1 was identified preliminarily as Pseudomonas aeruginosa, the strain B2 was identified preliminarily as Delftia sp., the strain B3 was identified preliminarily as Microbacterium sp., and the strain B4 was identified preliminarily as Alcaligenes sp.. The effect of temperature, initial pH, inoculation amount, initial concentration of tribenuron-methyl, medium volume, nitrogen source, carbon source and Mg^2 ＋concentration on growth efficiencies was studied. The results showed that B1 optimal temperature was 35 ℃, the rest were 30 ℃. B3 optimal initial pH was 8.0, the others were 7.0. B1 and B3 optimal inoculation amount were 15%, B2 and B4 optimal inoculation amount were 10%.B3 optimal initial concentration of tribenuron-methyl was 100 mg·L^-1, the other three were 200 mg·L^-1. The four bacterias optimal medium volume all were 75 mL, optimal nitrogen source were ammonium nitrate and optimal carbon source were glucose. B2 optimal Mg^2＋concentration was 100 mg·L^-1, the others were 200 mg·L^-1. B1 and B4 optimal sodium chloride concentration were 20 g·L^-1while B2 could grow well from 5 g·L^-1to 30 g·L^-1, B3 optimal sodium chloride concentration was 50 g·L^-1. The results provide theoretical basis for using bacterias in situ bioremediation of soil pollution of tribenuron-methyl.