Peroxidase Enzyme Bleaching of Pulp
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Solution Overview
Problem
Current pulp bleaching methods using chlorine and oxygen-based oxidants are inefficient and environmentally harmful, requiring multi-stage applications and failing to effectively remove lipophilic extractives, which cause pitch deposits and reduce pulp quality.
Innovation Solution
A method involving contacting pulp with a peroxidase classified as EC 1.11.1.7, a source of hydrogen peroxide, and a mediator with a specific chemical structure, such as violuric acid, at pH levels between 2 and 7, to enhance bleaching and remove lipophilic extractives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chlorine and oxygen-based oxidants are used for pulp bleaching, then bleaching effect is achieved, but environmental harm increases and multiple stages are required
Solution Approach 1:
The patent changes the chemical parameters of the bleaching system by using peroxidase enzymes instead of traditional chlorine and oxygen-based oxidants. This enzymatic approach operates under milder conditions (pH 2-7, lower temperatures) and achieves effective bleaching with reduced environmental impact, eliminating the need for multiple harsh chemical stages
Solution Approach 2:
The patent introduces mediators (compounds with specific chemical structures containing U1, U2, U3, R1, R2 groups) as intermediaries that facilitate the enzymatic action of peroxidase on lignin. These mediators enhance the bleaching efficiency of the enzyme system, allowing effective lignin removal while maintaining environmentally friendly conditions
2Object-affected harmful factors
If traditional bleaching methods are used, then some brightness improvement is achieved, but lipophilic extractives are not effectively removed
Solution Approach 1:
The patent utilizes the specific catalytic properties of peroxidase enzymes operating at pH 2-7 to selectively target and remove lipophilic extractives and pitch deposits that are resistant to traditional bleaching chemicals. The enzymatic mechanism provides different selectivity compared to conventional oxidants
Solution Approach 2:
The mediators used in conjunction with peroxidase have specific chemical structures that enable them to interact with and remove lipophilic substances. The mediator molecules can associate with pitch deposits and lipophilic extractives, facilitating their removal during the enzymatic bleaching process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves pulp brightness and reduces lipophilic extractives, thereby enhancing pulp quality and reducing environmental impact by using a more efficient and environmentally friendly process.
Implementation Method 1
contacting the pulp in an aqueous solution at from about pH 2 to about pH 7 with a peroxidase classified in EC 1.11.1.7
Implementation Method 2
a source of hydrogen peroxide
Data Source
AI summary
The use of a peroxidase and violuric acid, or a derivative thereof in the bleaching of pulp, such as paper materials, such as paper, linerboard, corrugated paperboard, tissue, towels, corrugated containers and boxes. The peroxidases of the invention are classified as EC 1.11.1.7. The effect of peroxidase is bleaching and de-inking of the pulp, e.g. the paper pulp and the resulting paper material.