Assessment of the dibenzothiophene desulfurization potential of indigenously isolated bacterial consortium IQMJ-5: A different approach to safeguard the environment

Abstract

Abstract Biodesulfurization is emerging as a valuable technology for the desulfurization of dibenzothiophene (DBT) and its alkylated substitutes, which are otherwise regarded as refractory to other physical and chemical desulfurizing techniques. However, the technique is currently facing the issue of the nonavailability of an effective microbial isolate with the capability of increased desulfurizing rate and the ability to tackle the problem of product inhibition. Pure cultures belonging to different genera have been used at a large scale for the desulfurization of fossil fuels while studies on the desulfurization of fossil fuels employing microbial consortia are entirely missing. Herein, we isolated several kinds of dibenzothiophene desulfurizing bacterial consortia from hydrocarbon-contaminated soil samples by conventional enrichment technique. The outcomes of Gibb’s assay analysis showed that six isolates followed the “4S” pathway and converted DBT to 2-hydroxybiphenyl (2-HBP). Among the isolates, I5 showed maximum growth rate (0.0064 g dry cell weight L-1h-1) and desulfurization activity (about 77% as indicated by HPLC analysis) and was considered for further in-depth experimentation. The analysis of 16S rRNA by high throughput sequencing approach of the I5 isolate revealed five types of bacterial phyla including Proteobacteria, Bacteroidetes, Firmicutes, Patascibacteria, and Actinobacteria (in order of abundance). The isolate showed significant tolerance to the inhibitory effect of both 2-HBP and sulfate and maintained growth in the presence of even about 1.0 mM initial concentration of both products. This clearly suggests that the isolate can be an efficient candidate for improving the quality of the coal.