Bacterial carriage and consortium development from artisanal refinery contaminated soil for effective degradation of petroleum hydrocarbons

Abstract

The bacterial carriage and consortium development from indigenous bacterial flora in crude oil-contaminated soil from artisanal refineries was studied. Surface soil samples were collected from four different communities in Emohua LGA, Rivers State, Niger Delta, Nigeria. Total culturable heterotrophic bacterial counts (TCHBC) and total culturable hydrocarbon-utilizing bacterial counts (TCHUBC) were monitored using the spread plate technique on nutrient medium and Bushnell Haas medium (supplemented with 1% v/v Bonny light crude oil) respectively. Nutrient enrichment process, hydrocarbon degradation screening and biosurfactant production analysis were used to detect bacterial isolates with hydrocarbon-degrading abilities to develop bacterial consortium. The 16S Illumina amplicon metagenomic analysis was used to identify the bacterial community diversity present in the consortium. TCHBC ranged from 2.3 x 10⁵ ± 0.28 CFU/g - 4.7 x 10⁷ ± 0.32 CFU/g, while TCHUBC ranged from 1.92 x 10⁴ ± 1.01 CFU/g - 3.7 x 10⁶ ± 0.04 CFU/g. Members of the phylum Proteobacteria (96.12%) were dominant in the consortium, while members of the phylum Verrucomicrobia (0.02%) had the least dominance. The genera Acinetobacter (19.6%) and Morganella (10.97%) were dominant in the bacterial consortium, while Akkermansia (0.02%) showed the least dominance. This study has demonstrated the successful development of bacterial consortiums using indigenous bacterial communities, which can serve as a bioresource for the recovery of hydrocarboncontaminated soils.