Biosynthesis of Pseudomonas aeruginosa mediated silver nanoparticles for remediation of crude oil contaminated water

Abstract

This study was aimed at biosynthesizing silver nanoparticle (AgNP) for remediation of total petroleum hydrocarbon (TPH) from crude oil-contaminated water samples from Nigeria's Niger-Delta ecosystem. The physicochemical and bacteriological analyses of the water samples were ascertained by standard techniques. Screening for hydrocarbon utilization was done for all isolates and the highest degrader was selected for biosynthesis of AgNP and characterized. TPH were adsorbed using the AgNP. The TPH response was designed and optimized using response surface methodology (RSM). The TPH in some of the water samples were above permissible limits in surface water given by Department of Petroleum Resources (DPR) and ranged from 6.55 ± 0.91 to 2324.36 ± 4.23 mg L⁻¹. The Total hydrocarbon utilizing bacterial counts ranged from 0.33 ± 0.01 × 10³ cfu mL⁻¹ to 13.67 ± 1.20 × 10³ cfu mL⁻¹. The isolate that recorded highest hydrocarbon degradation of 97.80% was identified as Pseudomonas aeruginosa strain AgA (PAE). The AgNP showed a peak at 425 nm, spherical, particle size distribution of 34.60 ± 13.04 nm, and a significant signal in the silver region, crystalline structure with an average mean crystallite size of 18.01504 ± 4.03 nm. The coefficient of determination (R²) had a value of 0.9190, the RSM for design and optimization demonstrated a satisfactory match for the 2FI regression model for the AgNP. At optimal contact time (22.5 min/100 mL), stirring speed (1620 rpm/100 mL), dosage (0.3206 g) and temperature (67.5 °C), the maximum expected TPH removal for PAE was 99.98%, demonstrating that the bacterial was helpful in synthesizing AgNPs to improve effective removal of pollutants from water.