Chitosan oligosaccharide-modified Pleurotus ostreatus mycelium for microplastic removal based on the green design concept

Microplastic particles are new pollutants that are difficult to recycle or biodegrade. Therefore, the development of an efficient and sustainable removal method is an urgent societal need. Recently, fungi was used for preparation of various of biomaterials due to their properties: biocompatibility, biodegradability, and bioactivity. Pleurotus ostreatus mycelium (PM), which is green, edible, cost-effective, and readily available, was firstly selected to construct good framework structure to remove microplastics. The PM was modified with the natural substances chitosan oligosaccharide and citric acid. Modified PM (M-PM) was shown to effectively remove microplastics, through a process known as adsorption, with 412.42 ± 9.14 mg of microplastics being removed by 1 g of modified mycelium. At room temperature, as high as 68.8 % of microplastics were removed by M-PM from tap water samples, and in other water samples the removal efficiency could reach 60.1 %-67.4 %. This remarkable removal ability was attributed to the cross-linked structure and surface cationization of the M-PM. Zeta potential and kinetic analyses showed that there was a substantial enhancement of electrostatic interactions. The biocompatibility and degradation experiments also showed that M-PM has good degradation ability and environmental compatibility. In summary, the M-PM has the advantage of being green and sustainable and may be a new material for removing microplastics. • Modified Pleurotus ostreatus mycelium (M-PM) increased microplastic adsorption. • About 70 % of the microplastics in real water samples was removed by M-PM. • M-PM has excellent biocompatibility and degradability. • This method is low-cost, sustainably produced and biodegradable.