Bacterial Laccase for Alkaline Lignin Depolymerization
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Solution Overview
Problem
Commercially available laccases are unstable and ineffective in alkaline conditions, which are necessary for chemical pulping and bleaching processes, limiting their use in delignification and lignin depolymerization.
Innovation Solution
A bacterial laccase with a specific amino acid sequence (SEQ ID NO: 1) that maintains activity at alkaline pH and elevated temperatures when in contact with lignin or lignocellulosic materials, allowing for stable depolymerization and delignification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commercially available laccases are used for lignin depolymerization, then the process can be performed under mild conditions, but the laccases are unstable and ineffective in alkaline conditions
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical properties of the laccase enzyme through fusion with a stabilizing protein domain. Specifically, the laccase is fused with a thermostable protein from Thermus aquaticus, which changes the enzyme's structural parameters to enhance stability at alkaline pH and high temperatures, thereby resolving the contradiction between reliability and adaptability
2Quantity of substance
If chemical pulping methods are used to remove lignin, then the bulk structure is broken down, but the process weakens the cellulose fibers
Solution Approach 1:
The patent replaces the harsh chemical pulping system with an enzymatic system using stabilized laccase. This substitution allows for selective lignin depolymerization through enzymatic action rather than chemical degradation, achieving effective lignin removal while preserving cellulose fiber integrity and strength
3Productivity
If mechanical pulping methods are used to separate fibers, then the fibers are physically separated, but much lignin remains adhered and energy consumption is high
Solution Approach 1:
The patent introduces stabilized laccase as an intermediary agent that facilitates lignin removal. The enzyme acts as a mediator between the lignin and the processing system, selectively degrading lignin to enable easier fiber separation while reducing energy requirements compared to pure mechanical methods
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
Enables effective lignin depolymerization and delignification at alkaline pH and high temperatures, overcoming the stability issues of previous laccases and enabling their use in industrial processes.
Implementation Method 1
a laccase with an amino acid sequence according to SEQ ID NO: 1 or an amino acid sequence at least 90% identical to SEQ ID NO: 1... wherein the lignin or lignocellulosic material is depolymerized
Implementation Method 2
Laccases are enzymes having a wide taxonomic distribution and belonging to the group of multicopper oxidases... which use molecular oxygen from air to oxidize various phenolic and non-phenolic lignin-related compounds
Data Source
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AI summary
The present invention is in the field of delignifying and/or bleaching of pulp, more in particular wood pulp. Such a process is useful in paper production. More in particular, the method relates to the use of an enzyme for delignification and/or bleaching, more in particular a bacterial laccase. Even more in particular, it provides a method for delignifying and/or bleaching of a pulp, comprising an enzymatic treatment step wherein lignin-containing pulp and a laccase are reacted at alkaline pH, wherein the laccase has an amino acid sequence according to SEQ ID NO: 1 or an amino acid sequence at least 90% identical to SEQ ID NO: 1.