Greater Biofilm Formation and Increased Biodegradation of Polyethylene Film by a Microbial Consortium of Arthrobacter sp. and Streptomyces sp.

Abstract

The widespread use of polyethylene (PE) mulch films has led to a significant accumulation of plastic waste in agricultural soils. The biodegradation of plastic waste by microorganisms promises to provide a cost-effective and environmentally-friendly alternative for mitigating soil plastic pollution. A large number of microorganisms capable of degrading PE have been reported, but degradation may be further enhanced by the cooperative activity of multiple microbial species. Here, two novel strains of Arthrobacter sp. and Streptomyces sp. were isolated from agricultural soils and shown to grow with PE film as a sole carbon source. Arthrobacter sp. mainly grew in the suspension phase of the culture, and Streptomyces sp. formed substantial biofilms on the surface of the PE film, indicating that these strains were of different metabolic types and occupied different microenvironments with contrasting nutritional access. Individual strains were able to degrade the PE film to some extent in a 90-day inoculation experiment, as indicated by decreased hydrophobicity, increased carbonyl index and CO2 evolution, and the formation of biofilms on the film surface. However, a consortium of both strains had a much greater effect on these degradation properties. Together, these results provide new insights into the mechanisms of PE biodegradation by a microbial consortium composed of different types of microbes with possible metabolic complementarities.

Effects of mulching film on soil microbial diversity and community of cotton

“…Further, Streptomyces may be critically involved in plastics’ degradation. Recently, Han et al ( 2020 ) found that a Streptomyces strain, isolated from agricultural soils, was able to grow with mulching film as carbon source and to thereby degrade the mulching film over time Therefore, we posit that Streptomyces is to some extent associated with PBAT’s degradation in the DPBOS treatment soil.…”

Microbial biodegradation of plastics: Challenges, opportunities, and a critical perspective

“…Consequently, the biofilm formation alters the polymer properties such as changes in functional groups, hydrophobicity/hydrophilicity, surface morphology, molecular weight, and crystallinity. Biofilm initiation enhances the carbon source utilization from immiscible substrates (Han et al, 2020). A recent study provided insights into the basis of biofilm formation on plastics (i.e., PLA, PET) surfaces and the role of conditioning films.…”

Aquatic Biofilms—Sink or Source of Microplastics? A Critical Reflection on Current Knowledge

“…It is therefore plausible that pristine microplastics practically do not exist in the aquatic environment. In addition, the biofilm on microplastics has been shown to harbor microorganisms capable of degrading plastics at a rather high abundance (McCormick et al, 2014), potentially contributing to their degradation in the environment (Han et al, 2020).…”