Presentation Information
[P02-234]Isolation and Characterization of a Polyvinyl Chloride-Degrading Bacterium
○Nelly Wira Nurhadi1, Miyuki Nagamine2, Hiroyuki Hamasaki3, Nobuaki Takahashi3, Kengo Inoue1,2 (1. Interdisciplinary Graduate School of Agriculture and Engineering, Department of Materials and Informatics, Course of Advanced Materials and Energy, University of Miyazaki (Japan), 2. Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki (Japan), 3. SHOWA GLOVE Co. (Japan))
Keywords:
Polyvinyl chloride,Biodegradation,Microbial community,Pseudoxanthomonas sp. strain VC007
[Purpose] The accumulation of polyvinyl chloride (PVC) waste has become a serious environmental concern due to its high chlorine content, chemical resistance, and the potential formation of hazardous chlorinated by-products during the conventional disposal processes. Therefore, the development of biological approaches for PVC degradation is of considerable interest.
[Method] In this study, aerobic microorganisms were enriched in a minimal medium supplemented with PVC (10 x 10 cm) as the sole carbon and energy source at 30°C and 180 rpm for 1—6 months. Soil and sediment samples were used as environmental inocula to selectively obtain PVC-degrading microorganisms.
[Results] After 112 days of incubation and three serial transfers, visible surface deterioration of PVC was observed. Scanning electron microscopy (SEM) revealed cracks and surface damage. Fourier-transform infrared (FT-IR) spectroscopy detected the emergence of new functional groups, particularly hydroxyl and carbonyl groups, suggesting oxidative modification of the PVC polymer. Microbial community analysis demonstrated that members of the families Bradyrhizobiaceae, Xanthomonadaceae, and Oxalobacteraceae were predominant in the enriched cultures. Bacterial isolation on tryptone-soya agar yielded two isolates. One isolate exhibited 100% 16S rRNA gene sequence similarity to Pseudoxanthomonas sp. which corresponded to the most abundant amplicon sequence variant detected in the community analysis. This isolate was designated Pseudoxanthomonas sp. strain VC007. To further assess the PVC-degrading potential of the strain VC007, degradation experiments were performed using a pure-culture system. The bacterial cells of strain VC007 were transferred into nitrogen supplemented mineral medium containing PVC (10 x 10 cm). After 60 days of incubation, no significant changes were observed on the PVC surface. However, visible discoloration of the PVC surface was detected after 99 days, indicating polymer deterioration. FT-IR analysis revealed a prominent absorption peak in the hydroxyl region, further supporting oxidative modification of the PVC polymer chain. SEM imaging showed widespread microbial colonization and bacterial attachment across the PVC surface.
[Conclusion] Although these results suggest the potential involvement of strain VC007 in PVC degradation, the underlying molecular mechanisms remain unclear. We are currently conducting genome analysis to identify enzymes and genes potentially involved in PVC degradation. Furthermore, we aim to elucidate the bacterial PVC degradation mechanism through subsequent transcriptomic analysis and intermediate metabolite profiling.
[Method] In this study, aerobic microorganisms were enriched in a minimal medium supplemented with PVC (10 x 10 cm) as the sole carbon and energy source at 30°C and 180 rpm for 1—6 months. Soil and sediment samples were used as environmental inocula to selectively obtain PVC-degrading microorganisms.
[Results] After 112 days of incubation and three serial transfers, visible surface deterioration of PVC was observed. Scanning electron microscopy (SEM) revealed cracks and surface damage. Fourier-transform infrared (FT-IR) spectroscopy detected the emergence of new functional groups, particularly hydroxyl and carbonyl groups, suggesting oxidative modification of the PVC polymer. Microbial community analysis demonstrated that members of the families Bradyrhizobiaceae, Xanthomonadaceae, and Oxalobacteraceae were predominant in the enriched cultures. Bacterial isolation on tryptone-soya agar yielded two isolates. One isolate exhibited 100% 16S rRNA gene sequence similarity to Pseudoxanthomonas sp. which corresponded to the most abundant amplicon sequence variant detected in the community analysis. This isolate was designated Pseudoxanthomonas sp. strain VC007. To further assess the PVC-degrading potential of the strain VC007, degradation experiments were performed using a pure-culture system. The bacterial cells of strain VC007 were transferred into nitrogen supplemented mineral medium containing PVC (10 x 10 cm). After 60 days of incubation, no significant changes were observed on the PVC surface. However, visible discoloration of the PVC surface was detected after 99 days, indicating polymer deterioration. FT-IR analysis revealed a prominent absorption peak in the hydroxyl region, further supporting oxidative modification of the PVC polymer chain. SEM imaging showed widespread microbial colonization and bacterial attachment across the PVC surface.
[Conclusion] Although these results suggest the potential involvement of strain VC007 in PVC degradation, the underlying molecular mechanisms remain unclear. We are currently conducting genome analysis to identify enzymes and genes potentially involved in PVC degradation. Furthermore, we aim to elucidate the bacterial PVC degradation mechanism through subsequent transcriptomic analysis and intermediate metabolite profiling.
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