Cell surface hydrophobicity and petroleum hydrocarbon degradation by biofilm-forming marine bacterium Pseudomonas furukawaii PPS-19 under different physicochemical stressors

Biofilm-forming marine bacterium Pseudomonas furukawaii PPS-19 showed strong hydrophobicity under different physicochemical stressors, such as pH and salinity. Strong aggregation of P. furukawaii PPS-19 was observed at hydrophobic interfaces of n-dodecane and crude oil, while uptake of pyrene resulted in blue fluorescence of the bacterium. Changes in biofilm microcolonies were observed under different physicochemical stressors with maximum biofilm thickness of 15.15 µm and 15.77 µm at pH 7% and 1% salinity, respectively. Relative expression analysis of alkB2 gene revealed the maximum expression in n-dodecane (10.5 fold) at pH 7 (1 fold) and 1% salinity (8.3 fold). During the degradation process, a significant drop in surface tension resulted in increased emulsification activity. P. furukawaii PPS-19 showed the respective n-dodecane and pyrene degradation of 94.3% and 81.5% at pH 7% and 94.5% and 83% at 1% salinity. A significant positive correlation was obtained between cell surface hydrophobicity (CSH), biofilm formation, and PHs degradation (P < 0.05) under all the physicochemical stressors, with the highest value at pH 7% and 1% salinity. Analysis of metabolites indicated that mono-terminal oxidation and multiple pathways were followed for n-dodecane and pyrene biodegradation, respectively. Thus, P. furukawaii PPS-19 is an efficient hydrocarbonoclastic bacterium that may be exploited for large-scale oil pollution abatement.