Screening, degradation characteristics, and fermentation optimization of aniline-degrading strain

Abstract:

[Background] In recent years, aniline compounds have aggravated the pollution of ecological environment, and biological treatment of aniline wastewater has great development potential and broad application prospect. [Objective] To isolate a strain that can degrade aniline efficiently from activated sludge contaminated by aniline compounds for a long term, and optimize its medium and degradation conditions to provide strain and gene resources for aniline bioremediation. [Methods] The high-efficient degrading bacteria with aniline as its sole carbon and nitrogen source and energy were screened out from the enriched and acclimated strains by plate method. The strain was identified by 16S rRNA gene sequence analysis. The degradation conditions were optimized by the single factor screening test, and the culture conditions were optimized by the orthogonal experiment. [Results] An aniline-degrading strain BA-6 was screened out and identified as Microbacterium sp. The strain removed more than 98% aniline with the initial concentration of 600 mg/L within 24 h. The efficient degradation temperature and pH for the strain BA-6 were 30-37 ℃ and 6.5-7.5, respectively. The substrate utilization test showed that the strain BA-6 had the ability to degrade many aniline compounds. The optimal fermentation medium was obtained, and the viability of the strain was up to 3.06×10¹⁰ CFU/mL. [Conclusion] Based on the strong abilities to degrade aniline and adjust to the environment, BA-6 strain has certain application potential in the remediation of ecological pollution of aniline compounds.

Key words:aniline;microbial degradation;degradation characteristics;optimization of fermentation conditions