We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Biodegradation of polyethylene with polyethylene-group-degrading enzyme delivered by the engineered Bacillus velezensis
Summary
Researchers engineered a strain of the soil bacterium Bacillus velezensis to produce enzymes that break down polyethylene, the most common type of microplastic found in vegetable-growing soils. The engineered bacteria degraded about 23 percent of polyethylene microplastics over 20 days in laboratory tests. The study introduces a promising bioengineering approach to tackling the widespread problem of plastic pollution in agricultural soils.
Microplastics (MPs) pose an emerging threat to vegetable growing soils in Harbin, which have a relatively high abundance (11,065 n/kg) with 17.26 of potential ecological risk of single polymer hazard (EI) and 33.92 of potential ecological risk index (PERI). Polyethylene (PE) is the main type of microplastic pollution in vegetable growing soils in Harbin. In this study, the engineered Bacillus velezensis with polyethylene-group-degrading enzyme pathway (BCAv-PEase) was constructed to enhance the degradation of MPs of PE (PE-MPs). BCAv-PEase increased the biodegradation of PE-MPs, promoted weight loss of PE films, elevated surface tension, and decreased the surface hydrophobicity of PE through upregulating activities of depolymerases, dehydrogenase, and catalase. Mechanism analysis showed that BCAv-PEase degraded PE-MPs by promoting the secretion of PEase, thereby leading to the generation of new oxygenated functional groups within the PE-MPs substrate, which further accelerated the metabolic pathway of PE-MPs. The analysis of the microbial community during the PE-MPs degradation processes revealed that BCAv-PEase emerged as the principal bacterial player and stimulated the abundance of microbes and functional genes associated with the biodegradation of PE. In conclusion, this study provides a potential mechanism for biodegradation of PE-MPs mediated by BCAv-PEase via modulating substrate selectivity and optimizing biocatalytic pathways.