Study On Enzymatic Hydrolysis Of Bagasse Treated With Phosphoric Acid-hydrogen Peroxide And Its Mechanism

In the context of energy,environmental crisis and "double carbon" goal,obtaining sustainable energy and materials from biomass has become very important,especially the urgency of obtaining fermentable sugars and "replacing plastic with paper".However,due to the multi-level winding of plant cell wall and the structural characteristics of hemicellulose shell,the accessibility of enzyme to cellulose is limited,resulting in low enzyme efficiency.In addition,the residue after enzymatic hydrolysis lacks effective utilization ways,which weakens the resource utilization efficiency.Using bagasse as raw material and phosphoric acid hydrogen peroxide pretreatment,this paper focuses on the effects of pretreatment on bagasse enzymatic hydrolysis,hemicellulose on bagasse enzymatic hydrolysis and residue on paper strength.The main results are as follows:(1)In order to remove the biological barrier of lignin carbohydrate complex to enzyme approaching cellulose,bagasse was pretreated with phosphoric acid hydrogen peroxide.In the process of treatment,～ 100 % hemicellulose and ～98 % lignin were removed,and the cellulose was partially dissolved.The treated bagasse has a porous and fluffy structure,the pore volume suitable for enzyme entry is increased by 11 times,and the surface area available for cellulase loading is increased by 5 times.This greatly improved the accessibility of enzyme to cellulose,and the recovery of glucose was as high as 98.60 %.The phosphate reagent can be reused and has little effect on the enzyme efficiency.(2)Hemicellulose had a significant effect on the enzymatic hydrolysis efficiency of bagasse.With the decrease of hemicellulose content from 18 % to0 % and the increase of glucose yield from 54.54 % to 95.36 %,the enzymatic hydrolysis efficiency increased by 20 times.This is explained by the sugar shell structure formed by hemicellulose wrapping cellulose,which prevents cellulase from approaching cellulose.(3)The major challenge of using traditional paper to replace plastics is the insufficient wet strength of paper.Inspired by the enhancement effect of lignin in natural plants on the water stability of cellulose,bagasse residue rich in lignin after enzymatic hydrolysis is used as the enhancement matrix to regulate the water stability of straw paper.Through the ability of nano cellulose in the residue to form hydrogen bond with fiber,lignin is successfully introduced into the fiber surface and the gap between fiber and fiber network,reducing the gap between fiber and fiber.As a "binder" and "hydrophobic agent",lignin inhibits the water absorption and swelling of cellulose,so as to maintain the stability of straw paper fiber network.Compared with traditional paper,the dry strength and wet strength of lignin reinforced straw paper were increased by 218 % and2233 % respectively.