Methyl Mercaptan Solubility in Enzymatic Methionine Synthesis
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Solution Overview
Problem
The existing chemical synthesis methods for L-methionine produce a mixture of L- and D-forms, leading to inefficiencies and by-products, while the biological two-step process faces challenges with sulfide toxicity and low solubility of methyl mercaptan, limiting productivity.
Innovation Solution
A method involving a mixture of methyl mercaptan and dimethyl sulfide in an enzymatic conversion reaction is used to improve the solubility and reactivity of methyl mercaptan, enhancing the conversion rate of L-methionine from its precursor, O-acetyl or O-succinyl homoserine, with specific enzymes like cystathionine gamma synthase and sulfhydrylase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If methyl mercaptan is used as a gas in the enzymatic conversion reaction, then the reaction can proceed, but its low solubility in aqueous solution limits productivity
Solution Approach 1:
Dimethyl sulfide is introduced as an intermediary substance that forms a soluble complex with methyl mercaptan in the aqueous reaction medium. This intermediary complex allows methyl mercaptan to remain dissolved and reactive without evaporating, thereby resolving the contradiction between maintaining reaction productivity and ensuring adequate solubility of the gaseous substrate.
Solution Approach 2:
The physical state and solubility parameters of methyl mercaptan are changed by combining it with dimethyl sulfide. This parameter change transforms methyl mercaptan from a poorly soluble gas into a soluble reactive complex within the aqueous solution, enabling sustained enzymatic conversion without loss of substrate to evaporation.
2Productivity
If conventional chemical synthesis methods are used, then methionine can be produced, but the product contains unwanted D-form impurities
Solution Approach 1:
The conventional chemical synthesis method is replaced with a biological enzymatic conversion system. This substitution replaces non-selective chemical reactions with highly specific enzymatic catalysis, where the enzyme cystathionine gamma synthase selectively converts O-acetyl homoserine to L-methionine without producing D-form impurities, thereby achieving both productivity and manufacturing precision.
3Productivity
If sulfide compounds are used in the enzymatic conversion, then methionine production is enhanced, but sulfide toxicity becomes a problem
Solution Approach 1:
Instead of using highly toxic hydrogen sulfide, the patent uses dimethyl sulfide as a safer alternative that copies the essential sulfide function needed for methionine synthesis. Dimethyl sulfide provides the necessary sulfur donor capability while being less toxic and more manageable in the reaction system, thereby maintaining productivity while reducing 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
This approach increases the production rate and purity of L-methionine and organic acids, offering economic benefits through improved productivity and yield, while avoiding the limitations of conventional methods.
Implementation Method 1
enzymatic conversion reaction for L-methionine production occurs in an aqueous solution
Implementation Method 2
a mixture of methyl mercaptan and dimethyl sulfide mixed at a appropriate ratio can improve the conversion rate
Data Source
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AI summary
The present invention relates to a method for increasing L-methionine productivity and organic acid productivity. More particularly, the present invention relates to a method which involves adding a mixture containing methyl mercaptan and dimethyl sulfide at a appropriate appropriateratioto O-acetyl homoserine or O-succinyl homoserine and to an enzyme having an activity of converting methionine precursor into L-methionine, so as to perform an enzyme reaction, to thereby improve the conversion rate of L-methionine and organic acid from the L-methionine precursor, and thus increasing L-methionine yield as compared to conventional method..