Production of biomodified bleached kraft pulp by catalytic conversion using Penicillium verruculosum enzymes: composition, properties, structure, and application

摘要: The global development of the bioeconomy is impossible without technologies for comprehensive processing of plant renewable resources. The use of proven pretreatment technologies raises the possibility of the industrial implementation of the enzymatic conversion of polysaccharides from lignocellulose considering the process’s complexity. For instance, a well-tuned kraft pulping produces a substrate easily degraded by cellulases and hemicelulases. Enzymatic hydrolysis of bleached hardwood kraft pulp was carried out using an enzyme complex of endoglucanases, cellobiohydrolases, β-glucosidases, and xylanases produced by recombinant strains of Penicillium verruculosum at a 10 FPU/g mixture rate and a 10% substrate concentration. As a result of biocatalysis, the following products were obtained: sugar solution, mainly glucose, xylobiose, xylose, as well as other minor reducing sugars; a modified complex based on cellulose and xylan. The composition of the biomodified kraft pulp was determined by HPLC. The method for determining the crystallinity on an X-ray diffractometer was used to characterize the properties. The article shows the possibility of producing biomodified cellulose cryogels by amorphization with concentrated 85% H3PO4 followed by precipitation with water and supercritical drying. The analysis of the enzymatic hydrolysate composition revealed the predominance of glucose (55–67%) among the reducing sugars with a maximum content in the solution up to 6% after 72 h. The properties and structure of the modified kraft pulp were shown to change during biocatalysis; in particular, the crystallinity increased by 5 …