Encapsulation of bio-wasted derived persimmon peel extract in loaded polyvinyl alcohol/gelatin aerogel for enhanced inactivation of pathogenic bacteria in domestic sewage treatment

This study investigates the loading of bio-waste-derived persimmon peel extract (PPE) using polyvinyl alcohol/gelatin (PVA/GEL) aerogel prepared using freeze drying technique to enhance the inactivation of pathogenic bacteria in domestic sewage The bioactive compounds in PPE were identified using GC-MS. Antioxidant tests showed that PPE had high phenolic content (95.16 ± 1.20 mg GAE/g), with strong free radical scavenging activity (IC50 % = 58.43 ± 0.95 µg/mL) and ferric reducing antioxidant power (FRAP value = 235.41 ± 3.45 µmol Fe²⁺ equivalents/mg). Antibacterial assays demonstrated dose-dependent efficacy, with inhibition zones up to 27 mm for Escherichia coli at 100 µg/mL. Antibacterial efficacy tests showed also a significant reduction in bacterial loads, with E. coli and Salmonella enterica exhibiting complete inactivation within 60 min of exposure. The utilization of PPE (3, 5 and 7 mL) blended with aerogel solutions (PVA and GEL) leads to the formation of PVA/GEL, PPE3@PVA/GEL, PPE5@PVA/GEL and PPE7@PVA/GEL aerogels. The PPE7@PVA/GEL aerogel achieved a 100 % reduction in biofilm formation for E. coli and over 90 % for other tested pathogens such as Klebsiella pneumoniae and Enterococcus faecalis. Toxicological assessments indicated minimal toxicity, with EC50 % values consistently over 100, highlighting the aerogel's safety for environmental applications. This study provides a sustainable approach to utilizing agricultural waste for environmental remediation and public health protection. Since, the aerogel was prepared from relatively cost effective and abundant polymers and containing a natural extract (PPE) exhibited a high efficiency in wastewater treatment.