科研之友
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摘要
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.
