Effects of polylactide/polybutylene adipate-co-terephthalate on bacterial community structure of soil and isolation of degrading bacteria

Abstract:

[Background] In recent years, the polylactide/polybutylene adipate-co-terephthalate (PLA/PBAT) mulch films has been widely used. However, the effects of PLA/PBAT mulch films on bacterial community structureits has rarely been reported. [Objective] The effects of PLA/PBAT mulch films on bacterial community structure was studied. And we isolated the PLA/PBAT degrading bacteria to provide technical support for in situ remediation. [Methods] The high-throughput sequencing method was used to compare the structural changes of bacterial communities in the Xinjiang soil before and after using the PLA/PBAT mulch films. The PLA/PBAT degrading bacteria were isolated by screening medium, and the degradation effects of the strains were studied by different culture conditions. [Results] After using PLA/PBAT mulch films, the abundance of Acidophilus and Bacillus were increased, and the abundance of Proteobacteria and Actinomycetes were decreased. This might be due to the inhibitory effect of intermediate products on pH and microorganisms during the degradation process of the PLA/PBAT mulch films. Moreover, a degrading strain XJ11 was isolated from the soil, which was initially identified as Delftia tsuruhatensis. In the screening medium, 1.5% tryptone was added, 1 mL of seed solution was inoculated, the pH of the medium was adjusted to 7.2, and shaker conditions was adjusted to 37 °C and 130 r/min. The degradation rate of PLA/PBAT mulch films (specification: 1 cm×1 cm×0.05 cm) can reach 6.87%. [Conclusion] The PLA/PBAT mulch films could change the bacterial community structure of soil. Screening the PLA/PBAT degrading bacteria from the environment was an effective measure to solve the pollution of mulch films.