Bioremediation of phenol by alkaliphilic bacteria isolated from alkaline lake of Lonar, India

Phenol is an industrially important compound which has a wide range of applications. Being highly soluble in water, it appeals as the major pollutant in waste waters arising from both phenol manufacturing and from industrial units that utilise phenol. Because of its toxicity, bioremediation of phenol is necessary. Since some of the phenol-bearing industrial waste waters are alkaline in nature, use of alkaliphilic bacteria for bioremediation of phenol was investigated. Alkaliphilic bacteria were isolated from sediments of an alkaline lake in Lonar, Dist. Buldhana, Maharashtra State, India, by phenol enrichment at pH 10.0 and phenol concentration of 500 mg/l. The lake (lat. 19 degrees 58'45 ", long. 76 degrees 34') is known to be a unique inland saline lake in Asia. It has a circular periphery and diameter of 2 km around the top of the banks and 1.2. km at the bottom. The lake has a high saline level (approximate to 2649) mg/l sodium chloride) and a high level of alkalinity (approximate to 2605 mg/l calcium carbonate). Alkaliphilic strains of Arthrobacter, spp., Bacillus cereus, Citrobacter freundii, Micrococcus agilis and Pseudomonas putida biovar B were capable of removing phenol from waste waters arising from industries manufacturing methyl violet (using phenol as one of the major raw materials) and cumene-phenol. The waste waters from both these units were alkaline in nature (pH approximate to 9.95-10.1) and had a high phenol content (368-660 mg/l). The alkaliphilic bacteria being studied removed 100% of the phenol from the industrial waste waters within 48 h of incubation under shake culture conditions and at an ambient temperature of 28 +/- 2 degrees C. Bioremediation of phenol by alkaliphilic strains of Arthrobacter, spp. B. cereus, C. freundii and M. agilis seems to be the first report.