Water Soluble Fraction of Crude Oil Uncouples Protease Biosynthesis and Activity in Hydrocarbonoclastic Bacteria; Implications for Natural Attenuation

Abstract

Three hydrocarbonoclastic bacteria isolated from crude oil-impacted mesotidal waters of the Niger Delta area of Nigeria, and identified, by 16S rRNA sequencing, as Vibrio fluvialis OWPB63, Serratia sp. MWPB18 and Pseudomonas fluorescens OWPB17 demonstrated commendable protease production ability in skimmed milk-minimal medium. Protease biosynthesis commenced in all three bacteria before the first 2 h of fermentation with peak productivities of 4.12, 0.73 and 1.12 μg/mL/h reached at 12, 36 and 48 h for Vibrio fluvialis, Serratia sp. and Pseudomonas fluorescens respectively. Activities of the enzymes assessed with azocasein as standard substrate were respectively 116.61, 174.56 and 145.84μg/mL/min. Median inhibition concentration (IC50) for Vibrio fluvialis enzyme biosynthesis, significantly (P