Study on Biodegradation of Naphthalene by Bacillus fusiformis

A strain of Bacillus fusiformis was isolated from activated sludge of a petroleum wastewater treatment plant and was used for the biodegradation of naphthalene in petroleum wastewater.The optimal experimental conditions are as follows:temperature is 30 ℃,pH is 6.68 to 6.76,inoculation rate is 0.2%,and(NH4)2SO4 concentration is 0.15 g/L.Under these conditions,the degradation rate of naphthalene reaches up to 99.8% within 96 h when the initial naphthalene concentration is 50 mg/L.In addition,the strain is able to tolerate salinity and high concentration of naphthalene.The naphthalene biodegradation process follows the first-order reaction kinetics.Furthermore,the strain's capability of degrading benzoic acid,salicylic acid,o-phthalic acid,toluene,phenol and 1-naphthol is shown by measuring the absorbance,pH and degradation of substrates during the treatment of different substrates.