To discuss the microbial structure that develops during the course of compost burials of polyvinyl alcohol (PVA)‐based material and analyze the effect of the degree of PVA alcoholysis on the PVA‐degrading ability of each strain. Two bacterial strains exhibiting a high level of PVA‐degrading ability and two mixed cultures were isolated from compost loaded with PVA‐based material. The rod‐shaped Gram‐positive bacterium DG22 was identified by 16S rDNA sequencing analysis as Bacillus sp. DG22, and the rod‐shaped Gram‐negative bacterium DG14 was identified as Paenibacillus sp. DG14. Biodegradation rates were determined by iodometric analysis within 8 days of culturing on selective media. The biodegradation rates for PVA1799 by DG22, DG14, T1 (mixed culture from a 36‐month burial), and T2 (mixed culture from a 24‐month burial) were 54.47, 46.59, 69.62, and 79.04%, respectively, and those of PVA1788 were 74.99, 67.27, 54.43, and 50.76%, respectively. DG22 and DG14 are the first known Bacillus sp. and Paenibacillus sp. able to utilize PVA solely. However, the higher degree of PVA alcoholysis (AD) had a negative effect on the biodegradation of PVA.

The aim of this work is to study the potential degradation of polyvinyl alcohol (PVA) by a novel fungus Eutypella sp. BJ isolated from soil compost. When it was cultured on a semi-synthetic medium containing PVA at 30 C and 160 rpm for 8 days, the removal rates of PVA 1788, 1799 and 2488 reached 87.40%, 86.31% and 44.80%, respectively. Gel permeation chromatography (GPC) analysis revealed significant reductions of the number average molecular weight and the weight average molecular weight of PVA 1788 from 47 358 to 13 345 and from 71 387 to 24 238, respectively, after 8 days. Fourier transform infrared spectroscopy (FTIR) indicated that some substances containing carbonyl groups (likely aldehydes or ketones) might have been produced during the biodegradation process. These results indicate that the isolate has potential for degrading PVA. This study provides the first demonstration that Eutypella has the ability to assimilate PVA.