Assessment of enhanced p-cresol biodegradation by encapsulating pre-immobilised Serratia marcescens strain HL 1 on tea waste biochar into polyvinyl alcohol/sodium alginate matrix

Abstract

In this study, the potential microorganism was isolated from activated sludge to degrade the p-cresol from wastewater. The isolated species (i.e., Serratia marcescens strain ΗL 1) was identified using a 16 S rRNA gene sequencing technique. Microorganism was immobilized into 1% (w/v) tea waste biochar and encapsulated into polyvinyl alcohol (PVA)/sodium alginate (SA) matrix to save the pure species from contaminant and able to sustain under high loading concentration. The maximum biodegradation efficiency was found to be 86.1 ± 2.0% of p-cresol by using PVA/SA (pre-immobilized (PI) (1%) biochar into PVA/SA) matrix which is much higher than the free cell (42.4 ± 0.7%) and immobilized system (73.8 ± 1.0). The % biodegradation of p-cresol was reduced from 86.1 ± 2.0–80.2 ± 1.4% after the fourth cycle. The matrix's surface morphology and the functional group were analysed by SEМ and FTIR, respectively. Monod and Andrew-Haldane model was used to identify biokinetic parameters. This research work revealed that an innovative PI(1%)biochar@PVA/SA matrix would be useful for the bioremediation of p-cresol. The main metabolic by-product obtained were 4-hydroxybenzoylalcohal (m/z = 124), 4-hydroxybenzoic acid (m/z = 138), maleic acid (m/z = 116) and acetaldehyde (m/z = 29)