Screening and characterisation of a poly(vinyl alcohol)-degrading mixed microbial culture

Abstract

A mixed microbial culture, which can degrade poly(vinyl alcohol) (PVA), was screened from the activated sludge of a textile factory. This mixed culture was found to consist of many bacterial strains, including representatives of Pseudomonas, Sphingopyxis, Castellaniella, Stenotrophomonas, Ochrobactrum and Shinella. The relative abundance of strains in the mixed culture during the incubation period was determined through the Illumina Miseq Platform. The biodegradation of PVA by this mixed culture in liquid medium was determined using several methods, including UV and gel-permeation chromatography (GPC). When the mixed culture was incubated in PVA1799-containing mineral medium for 4.5 days, the concentration of PVA decreased by 91% and the mean weight-average molecular weight of PVA decreased by 68%. The PVA-degrading enzymes produced by the mixed culture appear to be membrane or intracellular enzyme. The optimum pH and temperature for PVA-degrading enzyme activity were investigated by single-factor tests and were discovered to be pH 7.0 and 40°C, respectively. The crude enzymes extracted from the mixed culture could partly degrade PVA1799 nanofibre scaffolds.