Aspergillus sojae Mutant Strain for High Protease Activity
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Solution Overview
Problem
Current methods for producing protease and glutaminase enzymes used in soy sauce and Doenjang have low activity levels, limiting their effectiveness in flavoring, and are prone to contamination during solid-state fermentation, requiring high salt concentrations.
Innovation Solution
A mutant strain of Aspergillus sojae with enhanced protease activity is developed through N-methyl-N'-Nitroso-N-nitrosoguanidine treatment and irradiation, resulting in a strain with significantly higher protease activity, which is used to create a natural taste enhancer by hydrolyzing proteins, thereby increasing glutamic acid content and flavor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protease strains are used for protein hydrolysis, then the process is simple, but the protease activity level is low limiting flavor enhancement effectiveness
Solution Approach 1:
The patent applies mutagenesis treatment (UV irradiation and chemical mutagens) to induce genetic mutations in Aspergillus sojae, thereby changing the biological parameters of the strain to achieve enhanced protease activity. The mutant strain exhibits 5-8 fold higher protease activity compared to the parent strain, directly resolving the contradiction between reliability of flavor enhancement and productivity of enzyme activity.
2Ease of manufacture
If solid state fermentation is used for producing enzymes, then traditional methods are maintained, but contamination by various germs occurs requiring high salt concentrations
Solution Approach 1:
The patent transitions from solid state fermentation to liquid state fermentation, changing the physical state parameter of the fermentation medium. This parameter change eliminates germ contamination issues while maintaining traditional enzyme production capabilities, as the liquid culture system allows for better control and reduced contamination risk compared to solid state methods.
3Object-affected harmful factors
If liquid culture is used to exclude contamination, then germ contamination is reduced, but the enzyme activity level remains low
Solution Approach 1:
The patent combines liquid culture methodology with mutagenesis-induced strain improvement. By treating Aspergillus sojae with mutagens and selecting mutant strains with enhanced protease activity, the patent achieves both the contamination control benefits of liquid culture and the high enzyme activity needed for effective flavor enhancement, resolving the contradiction between these two requirements.
4Object-affected harmful factors
If high salt concentration is added to prevent contamination, then germ contamination is prevented, but the natural taste enhancer requires salt addition
Solution Approach 1:
The patent changes the fermentation state from solid to liquid, which fundamentally alters the contamination control mechanism. Liquid culture allows for sterile technique and controlled environments, eliminating the need for high salt concentrations used in traditional solid state fermentation. This enables production of natural taste enhancers without requiring subsequent salt addition for contamination prevention.
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 strain achieves a 5-8 fold increase in protease activity, producing a protein hydrolysate with high glutamic acid content, providing a rich, savory taste without the need for high salt concentrations, effectively addressing the limitations of existing enzyme activities and contamination issues.
Implementation Method 1
treating with N-methyl-N'-Nitroso-N-nitrosoguanidine (NTG) and inducing a mutation
Implementation Method 2
inducing a mutation through irradiation
Implementation Method 3
Protease degrades protein into peptides and amino acids
Implementation Method 4
glutaminase plays an important role in flavoring soy sauce, Doenjang, and the like, by converting free glutamine into tasty glutamic acid
Data Source
AI summary
The present invention relates to a mutant strain of Aspergillus sojae with an enhanced protease activity and a preparation method of a natural taste enhancer using the same. More specifically, the present invention relates to the mutant strain of Aspergillus sojae with an enhanced protease activity obtained by selecting a strain with high protease activity and treating it with N-methyl-N'-Nitroso-N-nitrosoguanidine (NTG) and inducing a mutation through irradiation, and a preparation method of a natural taste enhancer using protein hydrolysate obtained by