Bleaching compound enzyme for papermaking and preparation method of bleaching compound enzyme

Abstract

The invention discloses a bleaching compound enzyme for papermaking and a preparation method of the bleaching compound enzyme. The bleaching compound enzyme for papermaking, which has the advantages of complete enzyme system, good bleaching effect, easiness in preservation and good storage stability, is prepared by taking high temperature-resistant alkaline xylanase as main raw material, scientifically compounding a thermophilic bacillus culture, laccase and a medium thereof, dextranase, EDTA (ethylenediaminetetraacetic acid), a protecting agent, an activator, mannose, lipase, tannase, pectase, a whiteness stabilizer, a nonionic surfactant, an antioxidant and the like, completely retaining paper pulp cellulose and simultaneously dissolving out and degrading lignin to the greatest extent. The bleaching compound enzyme disclosed by the invention can significantly improve yield and quality of paper pulp against broad-leaf wood, coniferous wood and reed yellow slurry, and the whiteness is improved by 10.94%, 11.97% and 11.10% respectively; the yellow index is reduced by 39.84%, 37.31% and 24.32% respectively; the amount of conventional chemical products can be saved by 50-60%; and the purposes of reducing cost and protecting an environment are finally achieved.

Description

technical field [0001] The invention relates to a composite enzyme for papermaking, in particular to a bleaching composite enzyme for papermaking and a preparation method thereof. Background technique [0002] In industrial production, the pulping process is to remove lignin by high-temperature cooking under alkaline conditions. In order to make the purity of dissolved pulping cellulose reach 98%, this requires a large amount of sodium hydroxide to treat the pulp, resulting in Due to serious environmental pollution, many scholars have turned to biological treatment for pulping, and the xylanase used for pulping and bleaching should be heat-resistant and alkali-resistant. Feng Jianliang et al. (Kimura et al.2000) conducted a comparative experiment with xylanase pretreatment of wheat straw and conventional chemical pulping. Xylanase pretreatment improved the degree of delignification of raw materials and could also reduce the jam of pulping. primary value. Xylanase has been ...

AI Technical Summary

Problems solved by technology

Ligninase can directly act on lignin to degrade lignin, mainly lignin peroxidase, manganese peroxidase, laccase and cellobiose dehydrogenase secreted by white rot fungi. Research hotspots mainly focus on the biological bleaching of laccase, a multi-copper oxidase, also known as polyphenol oxidase, which mainly oxidizes phenolic lignin structural units, but only less than 20% of natural wood lignin In addition, fungal laccase has a large molecular weight (about 70,000 Da) and it is difficult to penetrate into wood to act on lignin molecules. To fully exert its enzyme activity, a laccase medium must be added, usually violuric acid (VA) and 1-hydroxybenzotriazole (HBT), depending on different bleaching processes, and the yield of laccase is small and the stability is poor

[0005] Chinese patent CN 102978986 A discloses a method for preparing pulp by biological enzyme method. The mass percentage content of biological enzyme components in the biological enzyme preparation liquid is: 20% cellulase, 10% hemicellulase, lignin degradation 10% enzyme, 20% amylase, 5% lipase, 20% pectinase and laccase; the cellulase in it will degrade the active ingredient cellulose in pulp, which is difficult to control and seriously affects the physical and mechanical properties of paper. At the same time, the above-mentioned biological enzymes are suitable for the pulping process, not the bleaching process, and the single use of laccase is difficult to exert its enzyme activity, and it cannot act on lignin well, and the possibility of pulp yellowing increases

Chinese patent CN 103555701 A discloses a production method of a compound enzyme solution for pulp bleaching, which is characterized in that the enzymes of each component are weighed, mixed and prepared in a compound tank, preserved, inspected, packaged, and then stored in a warehouse at 5°C. The enzymes of each component are alkaline pectinase, xylanase, mannanase and ligninase; the enzyme types and characteristics of the above-mentioned composite enzyme solution are single, the activity of ligninase is low, and the specific details of ligninase are not disclosed. species, industrialization is difficult to achieve, and lignin cannot be completely eliminated fundamentally, the bleaching effect is still unsatisfactory, and it is not easy to preserve, the storage stability is poor, and the commercial application is limited

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