Phage-Resistant Streptococcus Thermophilus Strains for Texturizing Dairy
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Solution Overview
Problem
The dairy industry requires novel texturizing strains of Streptococcus thermophilus that are resistant to bacteriophages commonly found in the food industry, as existing strains do not adequately provide both phage resistance and texturizing properties.
Innovation Solution
A method is developed to create phage-resistant mutant strains of Streptococcus thermophilus and Lactobacillus bulgaricus by exposing them to bacteriophages and introducing mutations in the galK regulatory sequence, resulting in increased phage resistance and texturizing capabilities, such as higher shear stress and gel stiffness during milk fermentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Streptococcus thermophilus strains are used for texturizing food products, then texturizing properties are achieved, but the strains are susceptible to bacteriophage attack
Solution Approach 1:
The patent applies the 'blessing in disguise' principle by exposing S. thermophilus strains to bacteriophage infection and selecting survivors that have developed phage resistance. The harmful phage attack is converted into a beneficial selection pressure that identifies strains with both phage resistance and maintained texturizing capabilities through polysaccharide production. This process transforms the vulnerability to phages into an advantage by identifying robust strains that can withstand industrial phage challenges while maintaining functional properties.
Solution Approach 2:
The patent employs parameter changes by modifying the physiological and genetic parameters of S. thermophilus strains through phage exposure and selection. The selected strains exhibit altered resistance parameters against bacteriophages while maintaining or enhancing texturizing parameters through increased polysaccharide production. This dual parameter optimization resolves the contradiction between phage susceptibility and texturizing effectiveness.
2Adaptability or versatility
If novel texturizing strains are developed, then texturizing properties are improved, but resistance to bacteriophages is not adequately provided
Solution Approach 1:
The patent transforms the harmful effect of bacteriophages into a beneficial selection tool by using phage challenge as a screening method. Strains are exposed to phages, and those that survive and maintain texturizing capabilities are selected. This converts the phage threat into a quality assurance mechanism that simultaneously improves both phage resistance and texturizing reliability.
Solution Approach 2:
The patent applies self-service by allowing the bacterial strains to naturally develop and express phage resistance mechanisms through selection pressure. The strains themselves provide the solution by producing protective polysaccharides and other resistance factors in response to phage exposure, eliminating the need for external addition of protective agents while maintaining texturizing functions.
3Productivity
If existing Streptococcus thermophilus strains are used, then production requirements are met, but both phage resistance and texturizing properties are not adequately provided simultaneously
Solution Approach 1:
The patent optimizes multiple parameters simultaneously by selecting S. thermophilus strains that exhibit improved phage resistance parameters while maintaining or enhancing fermentation productivity parameters. The selected strains demonstrate both increased resistance to bacteriophage infection and maintained or improved texturizing and acidification capabilities, resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent creates a composite functional profile in the selected bacterial strains that combines multiple desirable properties: phage resistance, texturizing capability through polysaccharide production, and fermentation productivity. This composite strain profile eliminates the need to choose between conflicting properties and provides a comprehensive solution meeting all industrial requirements simultaneously.
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 resulting strains demonstrate enhanced phage resistance and improved texturizing properties, generating higher shear stress and gel stiffness in fermented milk products, addressing the industry's need for strains that combine these characteristics.
Implementation Method 1
lactic bacteria are used intensively in order to bring about the acidification of milk (by fermentation) but also in order to texturize the product into which they are incorporated
Implementation Method 2
Certain of them play a dominant role in the development of the texture of the fermented product. This characteristic is closely linked to the production of polysaccharides
Implementation Method 3
The present inventors have provided a novel group of lactic acid bacteria of the species Streptococcus thermophilus and Lactobacillus bulgaricus, which surprisingly is more resistant to phage attack than the (mother) strain from which it is obtained
Data Source
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AI summary
The present invention relates to a bacterial cell with texturizing property, starter cultures comprising the cell, and dairy products fermented with the starter culture.