一株高效降解菲的植物内生细菌筛选及其生长特性

Isolation and characteristics of an efficient phenanthrene-degrading endophytic bacterium strain from plants

从长期受PAHs污染的植物看麦娘中分离出1株可高效降解菲的内生细菌Pn2,经生理生化特征分析和16S rDNA序列同源性分析,初步鉴定为Naxibacter sp.,研究了菌株Pn2的生长特性及其对菲的降解作用.结果表明,菌株Pn2能以菲为唯一碳源生长,并对菲有良好的降解性能.菲浓度为49.92mg/L时,30℃下150r/min振荡培养72h,菲降解率高达98.78%.接种量和污染强度显著影响Pn2对菲的降解：接种量越大,菲降解率越高;随污染强度升高,菲降解率先增大后减小,最适污染强度为150mg/L.菌株Pn2有较强的环境适应能力.温度为25~37℃、环境pH值为6.0~8.0、盐浓度1%~2%范围内,菌株Pn2生长状况良好.菌株Pn2为好氧生长,通气量越大,菌株生长越旺盛.菌株Pn2对低浓度的氨苄青霉素和氯霉素有抗性.

An efficient phenanthrene-degrading endophytic bacterial strain Pn2 was isolated from Alopecurus aequalis Sobol grown in PAH-contaminated soils.Pn2 was identified as Naxibacter Sp.based on physiological characteristics and 16S rDNA Sequence homology analysis.The experiments on phenanthrene-degrading features and growth characteristics of the strain showed that strain Pn2 can utilize phenanthrene as the sole carbon source.At 30℃ and 150 r/min,the degrading ratio of phenanthrene（49.92mg/L） in solution was 98.78% after 72 hours rotary culture.The inoculation amount and pollution intensity positively influenced the phenanthrene degradation： the larger amount of Pn2 inoculation,the higher phenanthrene degradation ratio.With increasing the pollution intensity,phenanthrene degradation ratio enlarged at first and reduced thereafter.150mg/L of phenanthrene is the optimum pollution intensity under the test condition.Pn2 grew well under the condition of 25~37℃,pH 6.0~8.0 and 1%~2% salinity.Strain Pn2 grew aerobically,and the stronger aeration,the better Pn2 growth.It was observed that Pn2 can resist the low concentration of penicillin and chloramphenicol.