title: Degradation kinetics and pathway of phenol byPseudomonasandBacillusspecies.
abstract: This article elucidates that strainPseudomonas aeruginosa(IES-Ps-1) is a versatile toxic organic compound degrader. With the degradation of malathion and cypermethrin (studied by other researchers previously), this strain was able to degrade phenol. Two other indigenous soil flora (i.e.,Pseudomonassp. (IES-S) andBacillus subtilis(IES-B)) were also found to be potential phenol degraders. Phenol was degraded with Monod kinetics during growth in nutrient broth and mineral salts medium. Before entering into the growth inhibition phase, strains IES-Ps-1, IES-S and IES-B could tolerate up to 400, 700 and 500 mg/L phenol, respectively, when contained in nutrient broth. However, according to the Luong-Levenspiel model, the growth of strains IES-Ps-1, IES-S and IES-B would cease at 2000, 2174 and 2190 mg/L phenol, respectively. Strain IES-Ps-1 degraded 700, 900 and 1050 mg/L phenol contained in mineral salts medium with the specific rates of 0.034, 0.075 and 0.021 h-1, respectively. All these strains grew by making clusters when exposed to phenol in order to prevent damages due to high substrate concentration. These strains transformed phenol into catechol, which was then degraded viaortho-cleavage pathway.
authors.affiliation: Department of Environmental Sciences, Sindh Madressatul Islam University Aiwan-e-Tijarat Road , Karachi - 74000 , Pakistan.
authors.forename: Syed Adnan
authors.initials: SA
authors.lastname: Hasan
authors.affiliation: Institute of Environmental Studies, University of Karachi , Karachi -75270, Pakistan.
authors.forename: Suraiya
authors.initials: S
authors.lastname: Jabeen
keywords: Bacillus; Pseudomonas; biodegradation; kinetics; phenol