Molecular Identification and Characterization of Bacillus sp. NIGAB-1 for Phenol Degradation Under Saline Conditions

Document Type: Research Paper


1 National Centre for Bioinformatics, Quaid-i-Azam University, Islamabad

2 Department of Plant Genomics and Biotechnology, National Institute for Genomics and Advanced Biotechnology, National Agricultural research centre, Islamabad, Pakistan

3 National Institute for Genomics and Advanced Biotechnology (NIGAB), National Agricultural Research Centre (NARC), Park Road, Islamabad-45500 Pakistan



Phenol is an aromatic pollutant in industrial wastes that in combination with salts is highly toxic for all forms of life. To alleviate this problem, 13 bacterial strains were isolated after enrichment in phenol (150 mg/L) containing mineral salt medium (MSM), and evaluated for phenol degrading potential under saline conditions. Among these isolates, bacterial strain NIGAB-1 was found capable of degrading phenol in saline conditions. This strain was identified as Bacillus sp. NIGAB-1 on the basis of 16S rRNA gene sequence analysis. Its closest match is Bacillus marisflavi with 99.71% sequence identity. Growth of strain was tested at different pH, NaCl concentrations and temperature. The Bacillus sp. NIGAB-1 exhibited best growth at 30oC in pH 7 with 10% NaCl. The strain was grown on mineral salt medium (MSM) containing phenol (0-750 mg/L) and 5% NaCl. Phenol degrading experiment was performed at 4% NaCl, pH 7 and 30 oC. In both, phenol tolerance and degradation a study, phenol was used a sole source of carbon and energy. The optimum phenol concentration for growth was recorded as 300 mg/L. This strain degraded 300 mg/L of phenol at 4% NaCl in 120 hours with the average degradation rate of 2.63 mg/L/hour.


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