Fermentation Broth Formulation Using Composite Acidification
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Solution Overview
Problem
Conventional methods for killing microorganisms in fermentation broths are harsh and can damage enzyme products, requiring costly containment procedures and using high concentrations of chemical agents, which are detrimental to enzyme stability and downstream applications.
Innovation Solution
A method involving a combination of a 1-5 carbon organic acid and a 6 or more carbon organic acid, in specific concentrations and under controlled pH and temperature conditions, to achieve a significant decrease in viable cells without interfering with enzyme activity, thereby preserving the stability and functionality of enzymes in the fermentation broth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods (heat, high concentration of single organic acid) are used to kill microorganisms, then cell inactivation is achieved, but enzyme product stability and activity are destroyed or altered
Solution Approach 1:
The patent uses a composite acidification approach combining mineral acid (e.g., sulfuric acid) with organic acid (e.g., acetic acid, propionic acid, or butyric acid) to achieve cell inactivation. This composite approach allows the mineral acid to provide strong initial acidification while the organic acid maintains lower overall acidity levels, thereby killing cells effectively while preserving enzyme stability and activity in the fermentation broth.
Solution Approach 2:
The patent changes the pH parameter gradually through two-stage acidification: first using mineral acid to lower pH to a moderate level (e.g., pH 3-4), then using organic acid to achieve final pH (e.g., pH 2-3). This controlled parameter change achieves cell inactivation while avoiding the extreme pH conditions that would destroy enzyme products, thus resolving the contradiction between killing cells and preserving enzymes.
2Reliability
If high concentration of single organic acid is used to kill cells, then cell inactivation is achieved, but downstream applications are inhibited and product cost increases
Solution Approach 1:
The patent employs a composite acid system combining mineral acid and organic acid, where the mineral acid provides the primary acidification effect and the organic acid provides supplementary acidification. This composite approach achieves effective cell inactivation while maintaining lower overall organic acid concentrations, thus avoiding inhibition of downstream enzymatic processes and reducing product cost.
Solution Approach 2:
The mineral acid acts as an intermediary that performs the bulk of the acidification work, allowing the organic acid to be used at lower concentrations. This intermediary approach enables effective cell killing while minimizing the concentration of organic acid that would otherwise inhibit downstream applications and increase product cost.
3Reliability
If low pH condition is used to kill microorganisms, then cell inactivation is achieved, but enzyme product stability is compromised
Solution Approach 1:
The patent implements a two-stage pH reduction strategy: first using mineral acid to lower pH to a moderate level (pH 3-4) where enzymes remain stable, then using organic acid to achieve the final lower pH (pH 2-3) required for cell inactivation. This controlled, staged parameter change achieves effective cell killing while minimizing exposure of enzymes to extreme pH conditions, thereby preserving enzyme stability.
Solution Approach 2:
The patent performs preliminary acidification using mineral acid to reach an intermediate pH level before adding organic acid. This preliminary action creates a buffer zone where the enzyme environment is already partially acidified but not yet at the extreme levels that would cause denaturation, allowing the subsequent organic acid addition to complete cell inactivation with minimal additional stress on enzyme stability.
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 approach effectively inactivates cells with a lower overall organic acid concentration, allowing for milder conditions that maintain enzyme activity, achieving at least a 4 log decrease in viable cells and retaining over 75% of the starting enzymatic activity.
Implementation Method 1
lowering the pH of the fermentation mixture using a mineral acid, followed by addition of a compatible organic acid and/or organic acid salt
Implementation Method 2
a high level of organic acid and a low pH is optimal... The low pH condition is often detrimental to the stability of many enzyme products
Data Source
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AI summary
The present disclosure relates to fermentation broth formulations containing organic acids and/or organic acid salts, and methods of making and using such formulations.