Cooperation of Lactoplantibacillus plantarum and polyethylene microplastics facilitated the disappearance of tetracycline during anaerobic fermentation of whole plant maize.

In agricultural production systems, the harm of both antibiotics and microplastics (MPs) to human health has been an important and continuously concerned issue. A small bagged silage production system was designed to investigate the effects of Lactoplantibacillus plantarum, polyethylene (PE) -MPs and their mixture on the silage fermentation and chemical composition of Tetracycline (TET) -contaminated whole plant maize. In addition, the bacterial community of silage samples was analyzed by using next generation genome sequencing technology. The formation of an extremely acidic environment (pH < 3.8) by ensiling effectively promoted the degradation of tetracycline (about 12.36 ng/ml), with PE-MPs particles also cleaved from 100 μm to 10 μm (in diameter) after 60 days of anaerobic storage. The PE-MPs physically adsorbed TET through its special pore structure and interacted with silage fermentation-dominated microorganisms including Lacticaseibacillus with relative abundances of 33-95 %, where the combination of PE-MPs and L. plantarum degrades tetracycline to 7.05 ng/ml. The PE-MPs inclusion enhanced the fermentation function of Lacticaseibacillus and stabilized the pH, ammonia nitrogen and other chemical indices of silage mass. Importantly, the co-occurrence of PE-MPs sustained also the dominance of desirable Lacticaseibacillus at late stage of ensiling with TET-contaminated maize. Therefore, the combination of PE-MPs and L. plantarum counteracted undesirable silage fermentation from TET contamination, reduced hypothetically the risks to animal and even human health by unappreciated use of antibiotics in agricultural production system.