Bleached compound enzyme and preparation method thereof

Abstract

The invention discloses a bleached compound enzyme and a preparation method thereof. The preparation method comprises the following steps: by taking high-temperature-resistant alkaline xylanase as a main raw material, scientifically compounding a bacillus thermophilus culture, laccase and media thereof, dextranase, EDTA, a protective agent, an activating agent, mannose, lipase, tannase, pectinase, a whiteness stabilizer, a nonionic surfactant and an antioxidant, dissolving the lignin to the greatest degree when the pulp cellulose is completely remained, degrading the lignin, thereby obtaining the bleached compound enzyme with the advantages of complete enzyme system, good bleaching effect, simplicity in preservation and good storage stability. According to the broadleaf wood, needlebush and reed yellow pulp, the pulp yield and quality can be obviously improved, and the whiteness is respectively improved by 10.94 percent, 11.97 percent and 11.10 percent; the yellowing value is respectively reduced by 39.84 percent, 37.31 percent and 24.32 percent; the amount of conventional chemicals can be saved by 50-60 percent; and finally, the aims of reducing the cost and protecting the environment are achieved.

Description

technical field [0001] The invention relates to a composite enzyme for papermaking, in particular to a bleaching composite enzyme 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 widely and deepl...

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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