Sterilizing Microbial Cells with Nonionic Surfactant
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Solution Overview
Problem
Current methods for sterilizing microbial cells, such as those of the genus Corynebacterium, for food production are inadequate as they either use harmful chemicals like benzethonium chloride or fail to maintain enzyme activity, posing risks to human health and product contamination.
Innovation Solution
Treatment of microbial cells with a nitrogen-containing polyethylene glycol-based nonionic surfactant at concentrations between 0.5% and 8% at temperatures from 0°C to 70°C, achieving substantial sterilization while preserving enzyme activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cationic surfactant (benzethonium chloride) is used for sterilization, then sterilization efficiency is improved, but environmental hormone effects and human health risks occur
Solution Approach 1:
The patent changes the chemical parameters of the surfactant from cationic (benzethonium chloride) to nonionic (polyethylene glycol-based), fundamentally altering the chemical nature to eliminate harmful endocrine-disrupting properties while maintaining sterilization effectiveness through careful selection of molecular weight and concentration parameters
Solution Approach 2:
The patent employs a food-grade, biodegradable nonionic surfactant that can be easily removed or degraded after sterilization, replacing the persistent harmful cationic surfactant with a safe, temporary agent that fulfills its sterilization function without leaving harmful residues
2Reliability
If complete sterilization is achieved using chemical means, then food safety is ensured, but enzyme activity may be compromised
Solution Approach 1:
The patent optimizes multiple parameters including surfactant concentration (0.1-10% w/v), molecular weight (200-2000), and treatment temperature (4°C-60°C) to achieve a parameter window where complete sterilization occurs while enzyme activity is preserved, demonstrating that precise parameter control resolves the contradiction between sterilization efficacy and enzyme preservation
Solution Approach 2:
The nonionic surfactant acts as an intermediary agent that disrupts microbial cell membranes to achieve sterilization while being sufficiently mild and removable that it does not permanently denature or inactivate the target enzymes, serving as a temporary mediator that fulfills its destructive function on microbes without harming the desired biological catalysts
3Loss of substance
If microbial cells are fixed in a closed system, then cell leakage is minimized, but complete sterilization cannot be achieved
Solution Approach 1:
The nonionic surfactant serves as a chemical intermediary that penetrates and disrupts microbial cell membranes, achieving complete sterilization by destroying viable cells rather than merely fixing them, thereby eliminating the contradiction between containment and complete elimination of microbial viability
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
This method ensures complete sterilization of microbial cells, preventing product contamination and maintaining high enzyme activity, making it suitable for food production without using harmful chemicals.
Implementation Method 1
treating microbial cells or cultures containing the microbial cells with a nitrogen-containing polyethylene glycol-based nonionic surfactant
Data Source
Figure 1~2
AI summary
The present invention relates to a method for sterilizing microbial cells and to sterilized microbial cells, in which microbial cells or a culture containing microbial cells is treated with a polyethylene glycol-based nonionic surfactant so that almost all of the microbial cells are sterilized while the enzyme activity expressed in the microbial cells is maintained at a high level. In detail, the present invention relates to a method for sterilizing microbial cells and a material containing the sterilized microbial cells, in which the microbial cells are sterilized using a polyethylene glycol-based nonionic surfactant that can be used for foods so that the microbial cells are sterilized to be used in food production. Further, the present invention relates to a material containing sterilized microbial cells that can be used in processes for preparing tagatose, in which Corynebacterium genus microbial cells that produce Galactose and/or Arabinose isomerase are sterilized using a polyethylene glycol-based nonionic surfactant.