Benzene Biodegradation During Growth by Aerococcus sp. Isolated from Oil Sludge

Abstract

Monoaromatic hydrocarbons such as benzene have been found in large quantities of sludge created by oil production facilities and industries. Benzene is highly volatile and soluble in water, it seeps into the ground and encounters water, sediment and soil layers of the environment. Benzene is considered as a carcinogenic substrate and biodegradation, principally under aerobic conditions, is an important environmental fate process for water and soil associated benzene. Aerococcus sp. strain BPD-6 was characterized in terms of its growth in presence of benzene (50-1000 mg L-1) as the sole carbon and energy source in the mineral salt medium. The maximum biomass growth was achieved at a pH of 7.0, temperature of 37 °C, with an initial benzene concentration of 50 mg L-1 and incubation period of 27 h. Various other monoaromatic compounds, such as toluene, ethyl benzene, and xylene were also tested as substrates for the growth of this bacterial isolate. The growth kinetics of the strain was analysed and the Haldane model was found to be a good fit for the experimental data with kinetic constants maximum specific growth rate (µmax)=0.02157 h-1, half saturation constant (Ks)=19.56 mg L-1, and substrate inhibition constant (Ki)=1584 mg L-1. The biodegradation rate kinetic parameter suggested that the strain can potentially be utilized in bioremediation of benzene and other monoaromatic compounds.