Biodegradation of polyvinyl chloride by Tenebrio molitor and its intestinal microorganisms

Abstract:

[Background] The accumulation of plastic wastes is an increasingly serious environmental pollution problem, and PVC, as common plastic, has a large number of production and consumption. [Objective] Based on the phenomenon that Tenebrio molitor feeds on plastics naturally, in this paper, the biodegradation of polyvinyl chloride (PVC) plastics by Tenebrio molitor larvae and its intestinal microbes was researched. [Methods] The weight increase of Tenebrio molitor larvae was observed after feeded polyvinyl chloride only, and fourier transform infrared spectroscopy (FTIR), screening of intestinal microbes and high-throughput sequencing methods were used to research biodegradation of PVC. [Results] The results showed that when PVC was used as the only carbon source of Tenebrio molitor larvae, after 32 d, PVC was consumed at the weight of 0.499±0.023 g per 200 Tenebrio molitor larvae, and the average weight of 200 Tenebrio molitor larvae was increased by 0.015±0.002 g. FTIR was used to detect the significant increase of carbonyl and hydroxyl content in PVC from excrement components, which indicates PVC degraded obviously. The results of high-throughput sequencing showed that Hafnia, Morganella, Escherichia coli and uncultured Enterobacteria were the dominant microflora. Compared with conventional feeding control, the abundance of Hafnia and Morganella increased by 35.20% and 16.42% respectively. [Conclusion] This article proved the biodegradation of PVC by Tenebrio molitor larvae and its intestinal microbes, and Hafnia and Morganella strains had the highest utilization of PVC. The results of the study have enriched scientific evidence for the biodegradation of “white pollution”.