Nowadays,there are many microplastic in our surrounding environment,and microplastic management poses a significant environmental challenge.Microplastic are generated in agriculture,fragmentating by Physical and Chemical Weathering,biological fragmentation and remobilization of plastic polluted sediments or soils.But it would be and extremely challenge to degrade these pollutants into an environmentally-benign form.Overall,this project represents how to recycling these plastic waste through PETase.
The first aims at reducing the plastic pollution by adding PETase enzyme to the gossamer. It can greatly alleviate the environmental damage caused by plastics. And then, we are going to establish a time-efficient platform to evaluate the efficiency of PET-degrading enzymes. We’re going to embed the enzyme in the fragments by gene editing, which can decompose the plastic and protect the environment.
About Spider Silk Protein
There have been 44,540 species of spiders.Spiders can produce a variety of silk fibers, each performing their own functions.The most thoroughly studied spider silk is Tusp,AcSp,Flag and Dragline.
The primary structure of spider silk protein is characterized by N-terminal(NT) non-repeating 130 amino acid segment and C-terminal(CT) non-repeating 110 amino acid segment.In addition,more than 90 percentage of sequences of spider silk proteins are repetitive regions which may affects the mechanical properties of silk fibres.
Within the repetitive regions,we determine the mechanical strength of the Tisp by the poly-Ala in the Tusp can spontaneously form an antiparallel β-sheet.And gave the Tusp good elasticity by GPGGX constitutes the crystal region that determines the thoughness of the filament.The 310-helix structure formed by Gly-Gly-X and β-spiral composed of Gly-Pro-Gly-Gln-Gln formed an amorphous region.
Figure 1:The structure of spider silk protein
Liquid crystal theory
One is a high concentration monomer;the other is to form a dimer with each other,which held together by a disulfide bond.In the process of spider drawing,the spinning fluid in the gland will move along the spinning duct,then spider silk proteins gradually seperate from each other,and finally transition to the liquid crystal state.
Micellee theory
As the spider continues to pull out the spinning fluid,formation of hydrophobic tail by dimerization.In this process,hydrogen bonds and other intermolecular interactions between spider silk proteins are gradually formed.Finally,the spider silk protein is transformed into spider filk fibre under the action.
Figure 2:Two mechanism of silk formation of spider silk protein
Spider silk is a natural material accessed by humans for millennia for various applications.A fatal fly trap, a firmly cross-winded nest, or even a vital safety rope from any surface, the most valuable characteristic of spider silk is nothing but its thinness and toughness. Therefore, why don't we also weave a fine and firm web with spider silk to catch those tiny malicious plastic particles in the environment? Inspired by the attributes of such natural material, we tend to synthesize a protein complex that consists of a plastic-degrading enzyme and spider silk, then apply it to capture and decompose floating microplastic in the ocean.
Also synthetic spider silk is of great significance in biological genetic engineering projects because it is a type of silk thread with good viscosity and toughness. In terms of good viscosity, it can help people collect small and unobservable particles, which undoubtedly greatly reduces pollution and optimizes the environment. Moreover, spider silk has good toughness, which can serve as a safety rope to reduce the occurrence of accidents.
PETase degradation is a new way to realize plastic waste recycling and the spider silk protein has excellent mechanical properties, good biocompatibility and degradability, and can also capture microplastics in the air. Using spider silk protein as a carrier and reacting with PETase, the microplastics can be decomposed efficiently and environmentally friendly, it can also reducing costs.
Tuo Yi,Prof. Qing Meng.Research on effects of repeat modules on properties of recombinant spidroins
Harry P. Austina,1, Mark D. Allena,1, Bryon S. Donohoeb,1, Nicholas A. Rorrerc,1, Fiona L. Kearnsd,1, Rodrigo L. Silveirab,e, Benjamin C. Pollardd, Graham Dominickc, Ramona Dumanf, Kamel El Omarif, Vitaliy Mykhaylykf, Armin Wagnerf, William E. Michenerc, Antonella Amoreb, Munir S. Skafe, Michael F. Crowleyb, Alan W. Thornea,Christopher W. Johnsonc, H. Lee Woodcockd,2, John E. McGeehana,2, and Gregg T. Beckhamc,2.Characterization and engineering of a plastic-degrading aromatic polyesterase
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