Degradation of Benzo [a] Pyrene by a novel strain Bacillus subtilis BMT4i (MTCC 9447)

Abstract

Benzo [a] Pyrene (BaP) is a highly recalcitrant, polycyclic aromatic hydrocarbon (PAH) with high genotoxicity and carcinogenicity. It is formed and released into the environment due to incomplete combustion of fossil fuel and various anthropogenic activities including cigarette smoke and automobile exhausts. The aim of present study is to isolate bacteria which can degrade BaP as a sole source of carbon and energy. We have isolated a novel strain BMT4i (MTCC 9447) of Bacillus subtilis from automobile contaminated soil using BaP (50 g /ml) as the sole source of carbon and energy in basal salt mineral (BSM) medium. The growth kinetics of BMT4i was studied using CFU method which revealed that BMT4i is able to survive in BaP-BSM medium up to 40 days attaining its peak growth (10 29 fold increase in cell number) on 7 days of incubation. The BaP degradation kinetics of BMT4i was studied using High Performance Liquid Chromatography (HPLC) analysis of BaP biodegradation products. BMT4i started degrading BaP after 24 hours and continued up to 28 days achieving maximum degradation of approximately 84.66 %. The above findings inferred that BMT4i is a very efficient degrader of BaP. To our best of knowledge, this is the first report showing utilization of BaP as a sole source of carbon and energy by bacteria. In addition, BMT4i can degrade a wide range of PAHs including naphthalene, anthracene, and dibenzothiophene therefore, it could serve as a better candidate for bioremediation of PAHs contaminated sites.

Identification and characterisation of oil sludge degrading bacteria isolated from compost

“…have been isolated and identifi ed from soil contaminated with oil refi nery wastewaters, which have the potential to biodegrade and utilise organic compounds such as PAHs of both low and high molecular weight as sole source of carbon (Gupta, 2012). Bacillus subtilis, which is one the dominant bacteria species identifi ed in this study have been reported to have the potentials to utilise several PAHs including benzo(a)pyrene, anthracene, naphthalene and dibenzothiophene as sole source of carbon energy (Lily et al 2009, Gupta 2012.…”

Identification of Benzo[ a ]pyrene-Metabolizing Bacteria in Forest Soils by Using DNA-Based Stable-Isotope Probing

“…The experiments were conducted as follows. Three grams of soil (dry weight) was placed in a 150-ml serum bottle containing 10 ml of phosphate-buffered mineral medium (32 13 C-BT, respectively. Eight samples were prepared for each treatment.…”

“…The genes coding for the mononuclear iron-containing catalytic domain (a conserved region) of PAH-RHD␣ (␣-subunit) have been widely used for studying RHD diversity and the PAH degradation potential by bacteria in the environment (11). In addition to the research on the genes involved in PAH degradation, studies using culture-dependent tools to investigate the degrading capacity of BaP degraders showed that rare bacteria were capable of metabolizing BaP without metabolic intermediate additives (9,10,13); in most cases, BaP degradation is stimulated by the addition of some intermediates produced during BaP metabolism (14,15). These intermediates possess the ability of stimulating PAH dioxygenase activity and are capable of supplying electrons for NAD (NADH) coenzymes, which are necessary for the functions of oxygenase enzymes, to initiate aerobic PAH degradation (8,16).…”

Production, Partial Purification and Characterization of α-Amylase from High Molecular Weight Polycyclic Aromatic Hydrocarbons (HMW-PAHs) Degrading Bacillus subtilis BMT4i (MTCC 9447)

“…Bacillus subtilis strain: The Bacillus subtilis BMT4i (MTCC 9447), isolated from automobile contaminated soil is an efficient degrader of HMW-PAHs including BaP, a potent carcinogen [16][17][18] was used in this study. The culture was maintained on nutrient agar slants at 4 o C.…”

“…In view of the above, the present study reports the production, partial purification, and characterization of α-amylase from a novel benzo-a-pyrene (BaP) degrading Bacillus subtilis BMT4i (MTCC 9447) previously isolated from automobile contaminated soil that is capable of degrading high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) including BaP [16][17][18]. Production conditions were also optimized (time, pH, carbon source, nitrogen source and CaCl 2 concentration) to achieve high enzyme production and better enzyme activity.…”