Streptococcus thermophilus GlcK Mutation for Fermented Milk Sweetness
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Solution Overview
Problem
The food industry faces challenges in developing fermented milk products with high natural sweetness without adding extra calories, as existing methods often rely on artificial sweeteners or genetically modified organisms that are not commercially viable, and natural sweetening strains like Streptococcus thermophilus struggle to maintain stability and growth rates when modified for enhanced sweetening and texturizing properties.
Innovation Solution
Introducing Streptococcus thermophilus strains with mutations in the glcK gene to inhibit glucose metabolism and the GalK gene promoter region to enhance galactose fermentation, allowing for increased production of exopolysaccharides, which improves texturizing properties without adverse effects on sweetening, resulting in strains that are stable and suitable for commercial production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Streptococcus thermophilus strains are modified to enhance natural sweetening properties by increasing glucose production from lactose degradation, then the sweetness of fermented milk products is improved, but the stability and growth rates of the bacterial strains deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the promoter region of the galK gene to alter gene expression levels. Specifically, the wild-type promoter is replaced with a mutated promoter that has enhanced activity, thereby increasing glucose production from lactose degradation while maintaining strain stability and growth rates suitable for commercial fermentation.
2Strength
If Streptococcus thermophilus strains are modified to enhance texturizing properties by increasing exopolysaccharide production, then the texture of fermented milk products is improved, but the stability and growth rates of the bacterial strains deteriorate
Solution Approach 1:
The patent applies parameter changes by mutating the promoter region of the galK gene to enhance its activity. This promoter modification simultaneously increases both glucose production (sweetening) and exopolysaccharide production (texturizing), thereby improving both sweetness and texture while maintaining strain stability and growth rates.
3Quantity of substance
If artificial sweeteners are added to fermented milk products to increase sweetness, then the sweetness is improved, but harmful factors are introduced
Solution Approach 1:
The patent applies self-service by enabling the Streptococcus thermophilus strain to produce its own sweetening compounds (glucose and exopolysaccharides) through modified lactose metabolism. The bacteria naturally convert lactose into sweet-tasting substances during fermentation, eliminating the need for external artificial sweeteners and their associated harmful effects.
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 modified Streptococcus thermophilus strains achieve enhanced natural sweetening and texturizing properties while maintaining sufficient stability and growth rates, enabling the production of fermented milk products with increased sweetness and texture without the need for artificial additives or genetic modification.
Implementation Method 1
Fermentation of the disaccharide lactose is very much studied in lactic acid bacteria because it is the major carbon source in milk. In many species, lactose is cleaved by β-galactosidase into glucose and galactose after uptake.
Implementation Method 2
lactose is cleaved by β-galactosidase into glucose and galactose after uptake. The glucose is phosphorylated by glucokinase to glucose-6-phosphate
Data Source
AI summary
The present invention relates to a Streptococcus thermophilus strain, wherein the strain is galactose-fermenting, wherein the strain carries a mutation in the DNA sequence of the glcK gene encoding a glucokinase protein, wherein the mutation inactivates the glucokinase protein or has a negative effect on expression of the gene, and wherein the strain carries a mutation in the promoter region of the GalK gene encoding a galactokinase protein.