African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5233

Full Length Research Paper

Isolation and characterization of a Bacillus strain for alkaline wastewater treatment

Kun Chen1, 2, Jing Yang1, 3 and Hua Zhao1, 3*
1Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, College of Bioengineering, Tianjin University of Science and Technology, Tianjin, China. 2School of Pharmaceutical, Liaocheng University, Shandong, China. 3Tianjin Key Laboratory of Industrial Microbiology, Tianjin, China.
Email: [email protected]

  •  Accepted: 08 October 2013
  •  Published: 07 November 2013


Biological treatment is one of the considerable choices for removing of organic pollutants present in petrochemical wastewaters. In this study, five strains, named as BS1, BS2, BS3, BS4 and BS5, were isolated from sludge close to a petroleum smelter. BS5, the isolate with the highest chemical oxygen demand (COD) removal rate, was identified as Bacillus flexus, based on 16S rDNA sequences. Subsequently, the optimized COD removal conditions of BS5 were investigated. It was indicated that the optimal conditions were 0.5% corn starch, 1% corn steep liquor, 35°C pH 7.5, and 10% (v:v) inoculation size. Under such circumstance, the removal rate of COD can reach 81.04%. The isolation of Bacillus flexus strain BS5 provided an alternative for the bioremediation of alkaline wastewater. Lastly, the study showed that consecutive disposal process may help to reducing COD of wastewater effectively.


Key words: Alkaline wastewater, Bacillus flexus, chemical oxygen demand (COD).