Screening and degradation characteristics of plastic-degrading microorganisms in film-mulched vegetable soil

In recent years, the incomplete recycle of residual mulch film (RMF) leads to the increasing richness of plastic fragment in soil, which poses a serious threat to the soil ecological environment. Therefore, the degradation of RMF in soil has aroused the interest of researchers. In this study, the degradation microorganisms were screened from film-mulched vegetable field, the results showed that seven potential plastic-degradation microorganisms were screened and identified, including four bacteria (Burkholderia cepacia, Burkholderia diffusa, Burkholderia aenigmatica, Chrysebacterium nepalense) and three fungi (Geotrichum candidum, Fusarium oxysporum and Tricho-derma sp.). The results of degradation ability experiments showed that the weight loss rate of single strains ranges from 1.58 to 2.44% after 90 d. The loss rate of weight-average molecular weight (Mw) and number-average molecular weight (Mn) for single strains after 30 d were 2.61-22.40% and 17.92-39.18%, respectively. In addition, the weight loss rate of the mixed strains ranges from 1.34 to 1.62% after 90 d. The loss rate of Mw and Mn for mixed strains after 30 d were 8.04-10.06% and 20.06-39.25%, respectively. The comparing results showed that there may be inhibitory interactions between microorganisms in mixed strains are culture. This research can provide theoretical basis and data support for the control and disposal measures of RMF pollution.