Schizosaccharomyces pombe Flocculating Mutant for Beta-Glucosidase Recovery
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Solution Overview
Problem
Current methods for enzymatic saccharification of cellulose face challenges due to glucose inhibition of β-glucosidase and cellobiose inhibition of endoglucanase and cellobiohydrolase, and require complex separation steps for recovering β-glucosidase from yeast cultures, especially as production scales increase.
Innovation Solution
A Schizosaccharomyces pombe mutant transformant is developed that exhibits non-sexual flocculation and increased β-glucosidase activity, using a cloning vector with the ihc1 or hsp9 promoter for efficient expression of β-glucosidase, allowing for easier protein recovery without complex separation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If filamentous fungi are used to produce cellulases, then various cellulases and hemicellulases can be produced and secreted in large amounts, but the genetic analysis is less advanced and gene transfer is more difficult compared to yeast
Solution Approach 1:
The patent uses yeast as an intermediary host organism to express fungal cellulase genes. The yeast system provides advanced genetic analysis tools and easy gene transfer capabilities while maintaining the ability to produce and secrete functional cellulases, thus mediating between the genetic ease of yeast and the enzymatic capability of filamentous fungi
2Ease of manufacture
If yeast is used as a host for β-glucosidase expression, then gene transfer is easier and genetic analysis is more advanced, but the yeast lacks endogenous β-glucosidase gene and cannot utilize cellobiose
Solution Approach 1:
The patent segments the cellulase system into multiple functional components expressed by different organisms: yeast expresses β-glucosidase to handle cellobiose conversion, while filamentous fungi provide the endoglucanase and cellobiohydrolase activities. This segmentation allows each organism to perform its specialized function without requiring the yeast to have all cellulase capabilities endogenously
3Quantity of substance
If conventional separation methods are used to recover β-glucosidase from yeast culture, then the enzyme can be obtained, but complex separation steps requiring tremendous labor and time are needed
Solution Approach 1:
The patent extracts the β-glucosidase production function from the yeast cell system and expresses it in a flocculating yeast strain that naturally aggregates and sediments. This allows the enzyme to be easily separated from the culture medium through simple sedimentation or filtration of the flocculated cells, extracting the separation complexity from the recovery process
4Productivity
If non-flocculating yeast is used for β-glucosidase production, then the yeast can grow and produce enzyme, but aggregated yeast cells are not easily separated from culture broth
Solution Approach 1:
The patent changes the physical parameter of yeast cell aggregation by using flocculating yeast strains that form large aggregates under specific cultural conditions. This parameter change from dispersed to aggregated cell states maintains enzyme production capability while dramatically improving the ease of separation through sedimentation or filtration
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
The mutant transformant enables efficient production and collection of β-glucosidase with reduced inhibition issues and simplified separation processes, enhancing the enzymatic saccharification of cellulose.
Implementation Method 1
using a cloning vector with the ihc1 or hsp9 promoter for efficient expression of β-glucosidase
Implementation Method 2
A Schizosaccharomyces pombe mutant transformant is developed that exhibits non-sexual flocculation and increased β-glucosidase activity
Implementation Method 3
the released cellobiose is degraded by β-glucosidase (BGL) to release glucose
Data Source
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AI summary
Provided is a transformant of S. pombe mutant which can produce and collect β-glucosidase without requiring complicated separation steps, and a vector which is useful for transforming a yeast of the genus Schizosaccharomyces. The transformant of a S. pombe mutant of the present invention is a transformant of a Schizosaccharomyces pombe mutant which exhibits an increased Gsf activity and decreased or no pyruvyl transferase Pvg1 enzymatic activity, and is comprised of a structural gene sequence encoding a β-glucosidase derived from a filamentous fungus, and a promoter sequence and a terminator sequence for expressing the structural gene in a chromosome or as an extrachromosomal gene. Further, the present invention relates to a cloning vector which is characterized by comprising a hsp9 gene promoter or an ihc1 gene promoter of a yeast of the genus Schizosaccharomyces, and is useful for transforming a yeast of the genus Schizosaccharomyces, an expression vector, a transformant, etc.