Biorefinery potential of Pseudomonas aeruginosa MB702 for crude oil degradation and poly-3-hydroxybutyrate (PHB) synthesis

Biodiversity and natural ecosystems are facing severe challenges as a result of plastic. Effective degradation of synthetic polymers and replacement with natural, environmentally acceptable biomaterials are urgently needed to help save the nature. Present study was focused on the potential of Pseudomonas aeruginosa MB702 to degrade crude oil and accumulate of poly-3-hydroxybutyrate (PHB) in their cell. Strain MB702 was isolated from the oil contaminated soil of Nashpa oil refinery Karak, Pakistan. Crude oil was selected to assess its suitability as an alternative low-cost carbon source that supports simultaneous hydrocarbon bioremediation and PHB biosynthesis, compared with glucose as a standard substrate. Pseudomonas aeruginosa MB702 exhibited 4.8% of dry cell weight accumulation of PHB using 2% crude oil and 16.9% PHB from 2% glucose as carbon source. The incubation period for crude oil degradation was seven days, while a shorter period of 24–48 h was employed for glucose. FTIR characterization of the biopolymer revealed distinctive bands of PHB at 1718 cm−1 to 1724 cm−1.GCMS analysis showed major peaks of polymer with carbon (C9-18). HPLC analysis depicted polymer at retention time of 2.6 min. Thermogravimetric analysis showed 80% degradation of the polymer at 384 °C and complete degradation (residual mass 0.12%) at 598 °C. Indigenous Pseudomonas aeruginosa MB702 isolated from an oil-contaminated site was used for simultaneous crude oil degradation and PHA production. This dual-purpose approach offers a novel strategy for sustainable biopolymer synthesis and environmental remediation.