Since the available literatures suggested that the ring opening followed by further cleavage of PAHs takes place at pH above neutral, Bacillus species with the said robustness (biosurfactant production as well as growth at alkali pH) have been the choice to study the degradation of PAHs. Thus, the present study exemplifies the biosurfactant mediated anthracene degradation efficacy of marine bacterial species in an aqueous medium. In brief, the study explores degradation of anthracene and finger printing of the degradative products using TLC, HPLC and GC–MS analyses. Further, the study extended to identify the genes responsible for the biosurfactant production and said degradation,
elucidation of degradation pathway and the schematic representation on the degradation process. Anthracene (99% purity) was purchased from HiMedia. Bacteriological selleck media, chemicals, silica gel coated TLC plates and solvents were purchased from Hi-Media and Sisco Research Laboratory (SRL), Mumbai, India. Isolate MTCC 5514 was initially screened from marine samples, characterized and identified according to the standard protocol and procedures and deposited in Microbial Type Culture Collection (MTCC), Chandigarh, India and used for the study. The 16S rRNA gene sequence was submitted CT99021 research buy to NCBI with the accession number HM145910. To the pre-sterilized medium (Zobell Marine Broth, (HiMedia)), anthracene at 100–1000 ppm
concentrations were supplemented aseptically and inoculated with the 1 × 105 cells/mL of MTCC 5514, incubated at 37 °C under shaking condition (200 rpm) for the period of 10, 16 and 22 days. Growth of the marine isolate MTCC 5514 in the presence of anthracene at varying concentrations,
viz., 0, 100, 300, 500, 750 and 1000 ppm was observed by measuring the optical density of the culture broth at 600 nm at 24 h intervals using UV–visible spectrophotometer (UV-2450, Shimadzu, Japan). The pH of the growth medium measured FAD at 24 h intervals till 22 days using Elico pH meter, model CL 54. The surfactant property of the extracellular medium during the growth of the isolate was qualitatively measured by drop collapse test and quantitatively by plate method using GBX-3S tensiometer (DM) at room temperature . Both synthetic (SDS, Tween 20, Triton X 100 (at 1% concentration)) and commercially available surfactant (Lecithin (at 10% concentration)) were used for comparison. Thin layer chromatography was used as a primary tool to identify the degraded products. Followed by removal of the samples, the cell free supernatant was mixed with ethyl acetate and the ethyl acetate fraction was separated and subjected to TLC analysis using chloroform:ethyl acetate:acetic acid (5:5:0.1) (v/v) as a solvent system and exposed to 2% Gibbs reagent after drying. Followed by the extraction with ethyl acetate, the samples were filtered through 0.