Polyurethane Foam Residue Biodegradation through the Tenebrio molitor Digestive Tract: Microbial Communities and Enzymatic Activity

Abstract

Polyurethane (PU) is a widely used polymer with a highly complex recycling process due to its chemical structure. Eliminating polyurethane is limited to incineration or accumulation in landfills. Biodegradation by enzymes and microorganisms has been studied for decades as an effective method of biological decomposition. In this study, Tenebrio molitor larvae (T. molitor) were fed polyurethane foam. They degraded the polymer by 35% in 17 days, resulting in a 14% weight loss in the mealworms. Changes in the T. molitor gut bacterial community and diversity were observed, which may be due to the colonization of the species associated with PU degradation. The physical and structural biodegradation of the PU, as achieved by T. molitor, was observed and compared to the characteristics of the original PU (PU-virgin) using Fourier Transform InfraRed spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), and Scanning Electron Microphotography (SEM).

Biodegradation of Typical Plastics: From Microbial Diversity to Metabolic Mechanisms

“…The global PU market is expected to grow at a compound annual growth rate of 3.8% from 2021 to 2028 [ 187 ]. Polyurethanes are highly resistant to high temperature and hydrophobic, resulting in a long service life [ 188 ]. The hardness and elasticity of polyurethanes can be tailored by controlling the ratio of each, causing them to be widely used [ 189 ].…”

Recent trends in insect gut immunity

“…Similarly, for polyurethane degradation by T. molitor’ s different gut microbiota, such as Paraclostridium , Chryseobacterium, Kosakonia , and Pseudomonas , were found to be responsible. During the degradation process, they can degrade the polymer by 35% within 17 days, but it experiences a weight loss of 14% ( 82 ). On the other hand, T. molitor’s gut microbiota breakdown long-chain and branched polymers by diffusing extracellular depolymerase, producing shorter chains containing 16 carbon atoms.…”

Reduction of polystyrene/polyurethane plastic wastes from the environment into binders for water-resistant emulsion paints

“…Polystyrene (PS) and polyurethane (PU) are among the plastic materials that significantly constitute solid waste [ 9 ]. Expanded polystyrene (EPS) is a low-additive grade of polystyrene materials that are majorly used in packaging and other structural applications [ 10 ].…”

“…), and many domestic and industrial structures and cushions [ 20 , 21 ]. PU materials are relatively biodegradable compared to PS [ 9 ]. However the process can be considered too slow for efficient PU waste management, while it may also generate another category of waste from the inorganic residue [ 21 ].…”