Study On Intestinal Multi-omics Of Tenebrio Molitor Larvae Feeding On Expanded Polystyrene

Polystyrene is one of the main types of synthetic plastics,which causes great pollution and extremely difficult to degrade in the natural environment.Studies have shown that Tenebrio Molitor larvae can feed on and degrade polystyrene plastics.In order to explore the functional genes,metabolic pathways,intestinal bacteria and the degradation and metabolism mechanism of expanded polystyrene in Tenebrio Molitor larvae,intestinal multi-omics,including the transcriptome and the metabolome,and the intestinal bacterial flora structure will be analyzed in this paper,which are from Tenebrio Molitor larvae fed on expanded polystyrene 0 days,10days,20 days and fed on bran 20 days,respectively.All these studies will lay theoretical foundation for the biodegradation mechanism of polystyrene.The main conclusions of this study are as follows:(1)Compared the results of eukaryotic transcriptome and untargeted metabolome in the intestines of Tenebrio Molitor larvae fed on expanded polystyrene for 0,10 and 20 days and fed on bran for 20 days,it showed that the effects of expanded polystyrene on Tenebrio Molitor larvae themselves were significant.Tenebrio Molitor larvae fed on Styrofoam for 20 days compared to those fed on bran for 20 days,the expressions of genes such as hydrolase activity and oxidoreductase activity in the intestines were significantly increased,and some pathways such as metabolism of xenobiotics by cytochrome P450,drug metabolism-cytochrome P450,drug metabolism-other enzymes related to the xenobiotics biodegradation and metabolism were Up-regulated expression.Through comprehensive analysis and q RT-PCR verification,it was confirmed that the related genes of cytochrome P450,microsomal epoxide hydrolase,dihydrodiol dehydrogenase and carboxy lyase were up-regulated in the intestines of Tenebrio Molitor larvae feeding on EPS,which may be related to the metabolism of expanded polystyrene.(2)Compared the results of high-throughput sequencing of full-length 16s r RNA amplifiers in the intestines of Tenebrio Molitor larvae fed on expanded polystyrene for 0,10 and 20 days and fed on bran for 20 days.It was found that compared with the Tenebrio Molitor larvae that ate bran for 20 days,the bacteria of Enterobacteriaceae,Erwiniaceae,Streptococcaceaeand Enterococcaceae were significantly increased in the intestinal bacteria of Tenebrio Molitor larvae fed on expanded polystyrene for20 days,which may be related to the metabolism of expanded polystyrene.(3)It is speculated that the metabolism of expanded polystyrene in the larvae of Tenebrio Molitor is as follows:after being chewed by the mouth parts and treated with stomach acid of Tenebrio Molitor larvae,the expanded polystyrene is randomly broken into long polystyrene chains of variable length.Under the action of cytochrome P450,the 2,3-sites of phenyl on the long chain are epoxidated to form ester intermediates.Then microsomal epoxide hydrolase hydrolyzes the ester intermediate to form hydroxyl groups at position 2,3-to form cis dihydrodiols.Then the H⁺on the 2,3-position is removed by dihydrodiol dehydrogenase to form cis diol with polystyrene as side chain.Then the benzene ring is broken from the 1,2-position by 2,3-dihydroxy dioxygenase to produce a meso-ring-opening compound.Then in the action of hydrolase,long chain acids and 2-hydroxy-2,4-dienopentanoic acid are generated.Carboxyl lyase removes the carboxyl group on the long-chain acid to form long-chain alkanes,which enter the degradation process of straight-chain alkanes.Straight-chain alkanes finally form short-chain fatty acids and acetyl-Co A;2-hydroxy-2,4-dienopentanoic acid forms pyruvate and acetic acid.Finally,these small molecules enter the tricarboxylic acid cycle and other processes,which provide the matter and energy for the normal life activities of the Tenebrio Molitor larvae,which feeds on the expanded polystyrene,and emits CO₂.