ISOLATION AND CHARACTERIZATION OF CRUDE OIL DEGRADING BACILLUS SPP.

today, application of microorganisms for removing crude oil pollution from contaminated sites asbioremediation studies, was considered by scientists because other methods such as surfactant washingand incineration lead to production of more toxic compounds and they are non-economic. fifteen crudeoil degrading bacillus spp. were isolated from contaminated sites. two isolated showed best growth inliquid media with 1-3% (v/v) crude oil and mineral salt medium, then studied for enzymatic activities ontested media. the results showed maximal increase in optical densities and total viable count concomitantwith decrease in ph on fifth day of experimental period for bacillus s6. typical generation time onmineral salt with 1% crude oil is varying between 18-20h, 25-26h respectively for bacillus s6 and s35.total protein was monitored at determined time intervals as biodegradation indices. increasing of proteinconcentration during the incubation period reveals that isolated bacillus can degrade crude oil andincrease microbial biomass. these bacillus spp. reduced surface tension from 60 (mn/m) to 31 and 38(mn/m), it means that these bacillus spp. can produce sufficient surfactant and have good potential ofemulsification capacity. the results demonstrated that these bacillus spp. can utilize crude oil as a carbonand energy source.