Biodegradation analysis of polyvinyl alcohol during the compost burial course

Abstract

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.

Keywords: 16S rDNA; biodegradation; degree of alcoholysis; polyvinyl alcohol.