Screening and community succession of high effective poly(butyleneadipate-co-terephthalate) plastic mulch degrading bacteria

Abstract:

[Background] Although poly(butyleneadipate-co-terephthalate)/PBAT plastic mulch is biodegradable, little is studied on its microbial degradation. [Objective] This study was to screen bacteria from different environmental samples for degrading PBAT plastic mulch. Through the analysis of community succession structure at multiple enrichment, the core microbe group of degrading PBAT plastic mulch bacteria was studied. [Methods] The modified SM inorganic salt medium was used to screen microorganisms that can degrade PBAT plastic mulch from different environmental samples. The efficiency of microbial degradation community was determined by weight-loss method. By using 16S rRNA gene high-throughput sequencing technology, the community structure from the fifth (G5) to ninth (G9) enrichment was studied. The relative abundance of different bacterial community and the PBAT plastic mulch degradation time were analyzed by Pearson correlation analysis. [Results] The biodegradable bacterial community capable of completely degrading PBAT plastic mulch was selected from the compost samples of Guangzhou Composting Plant and named SX. Through continuous transfer and enrichment, the degradation time of PBAT plastic mulch by bacteria SX decreased from 28 days (fifth, G5) to 13 days (9th, G9), indicating that the degradation rate of PBAT plastic mulch significantly increased. The high-throughput sequencing of the 16S rRNA gene showed that the relative abundance of Firmicutes gradually decreased in the fifth (G5) to ninth (G9) of PBAT plastic mulch degrading community, and the relative abundance of Actinobacteria gradually increased. The relative abundances of Arthrobacter sulfureus, Rhodospirillaceae, and Chitinophagaceae were gradually increased, however the relative abundance of Bacillus sp. was significantly decreased. Statistical analysis revealed that the relative abundance of Arthrobacter sulfureus was significantly associated with the reduction of PBAT plastic mulch degradation time (r=–0.927, p<0.05). [Conclusion] This study provided a green, highly efficient and environmental friendly new pathway and strain resource for the degradation of PBAT plastic mulch.

Key words:PBAT plastic mulch, Screening, Biodegradation, Community structure, Succession characteristics