Bio-fabrication of biodegradable polyhydroxybutyrate/polycaprolactone based sorbent: a net zero-waste approach for sustainable management of intricate hydrophobic pollutants.

Generation of secondary contaminants, insufficient sorption and recovery, and degradability issues associated with the existing solutions render the management of hydrophobic pollutants very challenging. Hereby, a cost-effective, energy-efficient, non-cytotoxic, biocompatible, and biodegradable sorbent is fabricated employing a blend of PHB and PCL biopolymers using a facile salt leaching technique. The sorbent demonstrated remarkable water repellence, achieving a saturated oil sorption capacity of 6.02 g/g for waste cooking oil (WCO) and 5.09 g/g for diesel oil, with recovery rates of 86.5 % for WCO and 85.7 % for diesel. Subsequent to the sorption of oils, the oil-saturated sorbents were further valorised through the production of biosurfactant utilizing the strain Pseudomonas aeruginosa AMS1a. The strain effectively produced biosurfactant with concentrations of 1040 mg/l and 546 mg/l utilizing WCO and diesel as carbon sources, respectively. Notably, 46.5 % of diesel-loaded sorbent and 23.72 % of WCO-loaded sorbent exhibited partial degradation during the valorisation process. The residual sorbents were buried in compost soil for further degradation, and were entirely decomposed within 28 days. The findings demonstrated an efficient biomaterial for addressing oil spill disasters while minimizing secondary contamination. Additionally, the sorbent also fulfilled the zero-waste notion of the Sustainable Development Goals (SDGs) defined by the United Nations.