Metagenomic signature and total petroleum hydrocarbons distribution in a crude oil contaminated ultisol remediated with biochar-humus sediment slurry

Ultisols are peculiar soils generally known for their poor nutrient status. When contaminated, remediation of ultisols present the additional challenge of nutrient and ecological restoration. In this study, we report the distribution of total petroleum hydrocarbons (TPHs) in a simulated crude oil-contaminated ultisol amended with biochar (BC)/humus sediment (HS) slurry. We also investigated the microbial abundance, diversity, and enzyme expression in the treatment medium that gave the optimum remediation results. We recorded lowest TPH levels in remediant amendments with BC produced at 700 degrees C. Majority of the OTUs (27.96%) found in the remediated ultisol belonged to Firmicutes (27.96%), Proteobacteria (25.88%), and Gemmatimonadetes (23.32%) while enzymes (AlkM, alkB, AlmA, PRM, cP450, MMO/AMO subunits A, B, and C, and Genes ssuD, ssuC, dszC, dszA, and dszB) encountered in this study were expressed mainly by bacteria belonging to the order Actinomycetales and Bulkhoderiales.