Anthracene biodegradation capacity of newly isolated rhizospheric bacteria Bacillus cereus S13

Abstract

Biodegradation of hazardous pollutants is of immense importance for maintaining a clean environment. However, the concentration of such contaminants/pollutants can be minimized with the help of microorganisms that has the ability to degrade the toxic pollutants into non-toxic metabolites. In the current study, 23 bacterial isolates were purified from the rhizospheric soil of Sysimbrium irio, growing as a wild plant in the vicinity of gas filling stations in Peshawar city. The isolated strains were initially screened on solid nutrient agar and further purified by culturing it on anthracene amended mineral media (PNR). The bacterial growth and anthracene disappearance were observed by calculating optical density (OD). The isolates showed a concentration-dependent growth on anthracene amended PNR media at 30°C and pH7. Also, an increase in bacterial OD from 0.351 to 1.80 with increased shaking speed was noticed. On the contrary, alternate carbon sources (glucose, fructose, sucrose) or nitrogen sources (KNO3, NaNO3, NH4NO3 and CaNO3) posed inhibitory effect on bacterial growth during anthracene degradation. The recorded efficiency of anthracene degradation by the selected bacterial isolate (1.4×1023 CFUmL-1 and 1.80 OD) was 82.29%, after 120 h of incubation. The anthracene was degraded to 9, 10, dihydroxy-anthracene and anthraquinone, detected through GC-MS. The efficient bacterial isolate was identified as S13, a new strain of Bacillus cereus, using 16S rRNA analysis, showing 98% homology. The isolated bacterial strain S13 may be used as a potential tool for bioremediation of toxic hydrocarbons and to keep the environment free from PAH pollutants.

Bacilli-Mediated Degradation of Xenobiotic Compounds and Heavy Metals

“…Anthraquinone was further degraded with the formation of phthalic acid, benzaldehyde or benzoic acid, and catechol. Metabolites of both of the pathways (9, 10-dihydroxyanthracene, anthraquinone, benzene acetic acid, and catechol) were also reported in the anthracene degradation pathway of B. cereus S13 that utilized it as the sole source of carbon and energy (Bibi et al, 2018 ). Another pathway of anthracene was studied in an alkaliphilic bacterium B. badius D1 that was able to degrade anthracene at a concentration of 50 mg/100 ml at pH 9.0 (Sarwade and Gawai, 2014 ).…”

“…Examples are Bacillus sp. SBER3 (Bisht et al, 2014 ), B. cereus JMG-01 (Das et al, 2017 ), B. licheniformis MTCC 5514 (Swaathy et al, 2014 ), B. cereus S13 (Bibi et al, 2018 ), and B . badius D1 (Sarwade and Gawai, 2014 ).…”

Different metabolic pathways involved in anthracene biodegradation by Brevibacillus, Pseudomonas and Methylocystis Species

“…S133 followed similar pathway with production of anthraquinone, phthalic acid, benzoic acid, and catechol (TMS derivatives) as metabolic intermediates [61]. Additionally, Bacillus licheniformis MTCC 5514 and Bacillus cereus S 13 followed the same pathway of anthracene biodegradation via anthraquinone, phthalic acid, benzoic acid, and catechol [33,62].…”

“…GC-MS analysis has been widely used in many previous studies to identify the byproducts and metabolic intermediates produced during different anthracene biodegradation pathways by various bacterial species [17,33,59,60]. Therefore, it was selected in the current study to detect the different metabolites produced during the anthracene biodegradation and to suggest the proposed anthracene biodegradation pathways followed by the selected strains.…”

“…The microorganisms degrade such pollutant compounds and convert them through mono and dioxygenase enzymes to inert substances, CO 2 , and water [28][29][30]. GC-MS analysis applied in many previous studies [31][32][33] is a technique used to detect the metabolites and the pathways involved in biodegradation.…”