Model Periphyton Biofilms: Biological System of Bioremediation of Synthetic Plastics

Abstract Humans have developed many materials with benefits which are unnatural. One such was the introduction of plastics in the early 20th century, which reaches its peak within the next 100 yr. Plastics are highly versatile and inexpensive materials, which are ubiquitous in modern life. Recycling plastics or reducing their use does not resolve the growing problem. Globally, the accumulation of plastics in water bodies has become a serious problem. Therefore, there is a need to degrade them in an environmentally-friendly manner. Despite having plenty of information on the degradation of plastics, only a few studies have reported the bioremediation of plastics. The present study aimed at microbial degradation of the five plastic films including polyamide (PA), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), and polypropylene (PP) using biofilm formation. The plastic films were exposed to waste water for 30 days. Microbial biofilms developed rapidly on the plastic samples within 3–4 weeks. PA and PVC films were covered with biofilms indicating the colonization process. Biodegradation was estimated in terms of weight loss and reduction rate. It was observed that PA mass decreased by 28.42%, followed by PVC (25.6%). The uptake rate of the PA by the biofilm was 0.0111 day–1 and the shortest half-life was observed for PA (62.44 days). The surface changes were visualized by scanning electron microscopy (SEM). SEM images revealed the attachment of the rod-shaped bacteria and the accumulation of different types of salts. Thus, the experiments provide an inventive bioremediation of plastics like PA followed by PVC using the environment–friendly biofilms.