Bioremediation of microplastics in freshwater environments: A systematic review of biofilm culture, degradation mechanisms, and analytical methods

Microplastics, defined as particles <5 mm in diameter, are emerging environmental pollutants that pose a threat to ecosystems and human health. Biofilm degradation of microplastics maybe an ecologically friendly approach. This review systematically summarises the factors affecting biofilm degradation of microplastics and proposes feasible methods to improve the efficiency of microplastic biofilm degradation. Environmentally insensitive microorganisms were screened, optimized, and commercially cultured to facilitate the practical application of this technology. For strain screening, technology should focus on microorganisms/strains that can modify the hydrophobicity of microplastics, degrade the crystalline zone of microplastics, and metabolise additives in microplastics. The biodegradation mechanism is also described; microorganisms secreting extracellular oxidases and hydrolases are key factors for degradation. Measuring the changes in molecular weight distribution (MWD) enables better analysis of the biodegradation behaviour of microplastics. Biofilm degradation of microplastics has relatively few applications because of its low efficiency; however, enrichment of microplastics in freshwater environments and wastewater treatment plant tailwater is currently the most effective method for treating microplastics with biofilms.

Automated summary

Microplastics are tiny particles with a diameter of less than 5 mm that pose a threat to ecosystems and human health. Biofilm degradation of microplastics is a potentially eco-friendly approach. This review summarizes the factors affecting biofilm degradation of microplastics and suggests methods to improve efficiency. Specifically, environmentally insensitive microorganisms are screened, optimized, and commercially cultured to facilitate practical application. The article also describes the biodegradation mechanism, with microorganisms secreting oxidases and hydrolases playing a key role. Measuring changes in molecular weight distribution allows for better analysis of microplastics biodegradation behavior. Currently, enriching microplastics in freshwater environments and wastewater treatment plant tailwater is the most effective method for treating microplastics with biofilms.