Paper pulp bleaching compound enzyme and preparation method thereof

Abstract

The invention discloses a paper pulp bleaching compound enzyme and a preparation method thereof. Through scientific compounding of high temperature-resistant alkaline xylanase as a main raw material and bacillus thermophilus culture, laccase and its medium, glucanase, EDTA, a protective agent, an activator, seminase, lipase, tannase, pectase, a whiteness stabilizing agent, a nonionic surfactant and an anti-oxidant, the paper pulp bleaching compound enzyme is prepared. The paper pulp bleaching compound enzyme completely retains paper pulp cellulose, maximally dissolves and degrades lignin, has the advantages of complete enzyme system, good bleaching effects, storage easiness and good storage stability, can substantially improve a yield and quality of paper pulp of broad leaf wood, needlebush and reed yellow waste slurry, respectively improves whiteness by 8.18%, 8.13% and 8.23%, respectively reduces a yellow index by 38.35%, 35.82% and 31.76%, saves a conventional chemical article use mount by 50-60%, reduces a cost and protects the environment.

Description

technical field [0001] The invention relates to a compound enzyme for papermaking, in particular to a pulp bleaching compound 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 delignification degree of raw materials and could also reduce the kappa number of pulping. . Xylanase has been widely and deeply re...

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 CN102978986A 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, 10% lignin degrading enzyme %, 20% amylase, 5% lipase, 20% pectinase and laccase; the cellulase in it will degrade the active ingredient cellulose in the pulp, which is difficult to control and seriously affects the physical and mechanical properties of the paper. At the same time, The above biological enzymes are suitable for the pulping process, not the bleaching process, and the single use of laccase, the enzyme activity is difficult to play, can not work well on lignin, and the possibility of pulp yellowing increases

Chinese patent CN103555701A discloses a production method of a composite enzyme liquid 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 liquid are single, the activity of ligninase is low, and the specific type of ligninase is not disclosed. Industrialization is difficult to achieve, and lignin cannot be 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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