T. VELAYUTHAM, V. ARUTCHELVANA, D.J. ALBINOB AND N. ASHOK KUMARA
Abstract
A strain of Bacillus subtilis has been isolated and identified using 16s rRNA gene sequencing method. The adaptation effect of the isolated species to the biodegradation of naphthalene and anthracene in a batch reactor was studied. Bacillus subtilis degraded both naphthalene and anthracene at an initial concentration of 100 and 50 mg/L to a maximum of 98.1 and 96.5 % at a HRT of 108 and 170 h, respectively. The maximum specific growth rates (µmax) of naphthalene and anthracene were found to be 0.0072 and 0.0051 h-1, respectively. The kinetic parameters were estimated using Monodâs, Haldaneâs, Linearized-Haldaneâs models for these two substrates and also determined the root mean square error (RMSE). The kinetic constants of cell growth under Haldaneâs model were satisfactory when compared to other models. The Haldaneâs model provides an excellent prediction of the growth kinetics and found to be in the range of µmax = 0.0141 and 0.007 h-1, Ks = 66.24 and 36.6 mg/L and Ki = 293.63 and 149.8 mg/L for naphthalene and anthracene, respectively. Besides, the yield coefficient (Y) for the growth of the isolate on both the substrates was 0.56, 0.51 mg/mg, respectively.