Production of Polyhydroxyalkanoates (PHAs) from Oil Palm Waste Using Paraburkholderia sp. PFN29

Abstract

The increasing accumulation of plastic waste has intensified efforts to identify sustainable biodegradable alternatives. Polyhydroxyalkanoates (PHAs) are microbial polyesters with properties similar to conventional plastics; however, their commercial feasibility is limited by high production costs. This study investigated the use of oil palm waste, specifically palm kernel meal (PKM) and empty fruit bunch (EFB), as feedstocks for PHA production by Paraburkholderia sp. PFN29. Biomass pretreatment used sodium hydroxide (1-5% w/v) followed by hydrogen peroxide (3% v/v), and enzymatic hydrolysis with pectinase, xylanase, and cellulase. Reducing sugars were quantified using the dinitrosalicylic acid (DNS) method, and morphological changes were examined via scanning electron microscopy (SEM). Optimal saccharification with 3% (w/v) NaOH at 50°C for 48 h yielded 10.53±0.33 and 21.02±0.38 mg/mL reducing sugars from PKM and EFB, respectively. Glucose was the predominant sugar in both hydrolysates. PHA biosynthesis was assessed under various carbon- and nitrogen-supplementation conditions. The EFB hydrolysate at 100 ml supplemented with 0.1 g NH₄Cl produced the highest PHA concentration (1.12±0.02 g/L), PHA content (59.02%), and productivity (0.01 g/L/h), which was comparable to that of the mineral medium control. The PKM hydrolysate supported optimal PHA production without supplementation (PHA content, 39.02%). Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) analyses confirmed PHB-type PHA production. These findings indicate that palm oil residues, particularly EFB hydrolysates under optimized nitrogen conditions, are promising substrates for sustainable PHA production.