Acenaphthene biodegradation and structural and functional metagenomics of the microbial community of an acenaphthene-enriched animal charcoal polluted soil

Abstract Animal charcoal from skin and hides cottage industries indiscriminately disposed in run offs and drainage channels harbors hazardous constituents that are mutagenic and toxic, and thus require bio-based eco-friendly depuration strategies. A microbial consortium (FN7) from an animal charcoal polluted site enriched with acenaphthene was structurally and functionally characterized via illumina next generation sequencing and annotation of their putative ORFs, and also studied for ability to degrade acenaphthene. Structurally, FN7 metagenome consists of 7 phyla, 13 classes, 38 orders, 49 families, 67 genera, 68 species, and 45 strains, respectively. The dominant phylum, class, order, family, genus, species, and strain in the metagenome are Proteobacteria (48.9%), Actinobacteria (31.8%), Actinomycetales (28.0%), Enterobacteriaceae (18.9%), Paracoccus (12.9%), Bacillus cereus group (13.5%), and Methylobacterium radiotolerans JCM 2831 (22.4%). The microbial consortium in the metagenome degraded 59.68% (29.84 mg l-1) and 89.16% (44.58 mg l-1) of the initial concentration of acenaphthene (50 mg l-1) in 14 and 21 days. Functional annotation of the putative ORFs of the metagenome using KEGG KofamKOALA, NCBI’s conserved domain database, BacMet, and Antibiotic Resistance Gene-ANNOTation (ARG-ANNOT) revealed the detection of hydrocarbon-degradation genes including salicylaldehyde dehydrogenase and catechol 1,2 dioxygenase involved in acenaphthene degradation, resistance genes for mercury, arsenic, cadmium, nickel, and several others, and antibiotic resistance genes for 15 antibiotic classes such as β-lactam, colistin, aminoglycoside, among others. This study revealed that members of FN7 metagenome are equipped with requisite gene batteries and could be veritable bioresources for in vitro biodegradation as well as on-site bioremediation of animal charcoal polluted sites.