高效苯酚降解菌Bacillus sp.L5-1的分离及其降解特性

从污水处理厂活性污泥中分离筛选出一株高效苯酚降解菌L5-1，经菌落形态观察和16S rDNA基因测序，结果表明菌株L5-1为蜡样芽胞杆菌（Bacillus cereus），美国国家生物信息中心（NCBI）的注册号为MN784421.将苯酚设置为唯一碳源，对其生长和苯酚降解特性展开研究.结果表明：菌株L5-1在10%接种量、温度30~35℃、pH值7~8的条件下，均能高效降解培养基中苯酚（培养基体积为100mL，初始苯酚浓度为500mg/L，14h时降解率>93%）.而在最优降解条件下（10%接种量，培养温度为35℃，pH值7.0，NaCl浓度为1%），初始苯酚浓度为500mg/L，菌株在14h内的苯酚降解率可达97.1%；而当初始苯酚浓度为1000mg/L，菌株也可在46h内达到97.71%的降解率.运用Haldance方程动力学模拟菌株在不同浓度苯酚下的生长过程，其最大比生长速率为0.355h^-1，半饱合常数104.27mg/L，抑制常数为322.83mg/L，R²=0.997.菌株L5-1为目前已报道的Bacillus菌属中降解苯酚能力较强的菌株，为实际处理含酚废水中提供理论参考.

Isolation and degradation characteristics of highly efficient phenol-degrading bacteria Bacillus sp. L5-1

A highly efficient phenol-degrading bacterium named L5-1 was isolated and screened from the activated sludge from a sewage treatment plant. The colony morphology observation and 16S rDNA gene sequencing showed that the strain L5-1 was Bacillus cereus, with the registration number of MN784421 in the US National Center for Biotechnology Information (NCBI). A series of experiments with Phenol as the only carbon source were conducted to study the growth and phenol degradation characteristics of this strain L5-1. The results showed that under the conditions of 10% inoculum, temperature range of 30 to 35℃, pH range of 7 to 8, the strain L5-1 effectively degraded phenol in the culture medium (with the 100mL of medium volume and the initial phenol concentration of 500mg/L), the degradation rate was better than 93% in 14h. Under optimal degradation conditions (10% inoculum, culture temperature at 35℃, pH 7.0, and NaCl concentration at 1%), The phenol degradation rate reached 97.1% within 14 hours when the initial concentration was set at 500mg/L. When the initial phenol concentration was set to 1000mg/L, the strain L5-1 still reached 97.71% degradation rate within 46 hours. The Haldane kinetic model was used to simulate the growth process of strains under different concentrations of phenol. The maximum specific growth rate was 0.355h^-1, the semi-saturation constant was 104.27mg/L, the inhibition constant was 322.83mg/L, R²=0.997. This study confirmed Strain L5-1 was a Bacillus strains with strong phenol degradation ability among the reported strains of the genus Bacillus, and provided certain theoretical references for the actual treatment of phenol-containing wastewater.