Polystyrene Biodegradation by Tenebrio molitor Larvae: Identification of Generated Substances Using a GC-MS Untargeted Screening Method

A GC-MS method has been applied to screen and evaluate the generation of chemical compounds during the biodegradation of polystyrene (PS) with Tenebrio molitor larvae. Several resulting compounds have been identified, including trimers 2,4,6-triphenyl-1-hexene and 1,3,5-triphenylcyclohexane, the volatiles acetophenone and cumyl alcohol, and 2,4-di-tert butylphenol, a non-intentionally added substance (NIAS) present in the plastic material. The PS monomers styrene and α-methyl styrene were also identified in the extracts. Bioactive molecules present in the biomass of the studied insects were identified, such as the free fatty acids myristic, palmitic, and oleic acid. Undecanoic acid was also found, but in lower mass fractions. Finally, biochemically formatted amides resulting from their respective fatty acids were identified, namely tetradecanamide, hexadecanamide and oleamide. The formation of all these substances seems to suggest enzymatic and biochemical activity occurring during the biodegradation of PS, and their amounts varied throughout the experience. The overall degradation rate of PS resulted in a 13% rate, which highlights the potential of biorecycling using these insects.