Methanosarcina acetivorans HdrABC Mutation for Methane Production
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Solution Overview
Problem
Current methods for industrial-scale biological methane production are limited by slow rates and the genetic intractability of methanogenic microbes, making it difficult to genetically engineer strains suitable for commercial-scale biogas production.
Innovation Solution
Development of a genetically engineered Methanosarcina acetivorans strain with a mutated HdrABC nucleic acid molecule, specifically a M249V substitution, which increases methane production rates when cultured under appropriate conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional methanogenic microbes are used for methane production, then the process is simple, but the production rate is slow
Solution Approach 1:
The patent applies parameter changes by mutating specific amino acid residues in the HdrABC enzyme (positions 249, 250, and 251 in HdrB) to alter its catalytic efficiency. The M249V substitution and other mutations in the HdrABC complex change the enzyme's kinetic parameters, resulting in a 28.9% increase in methane production rate from methanol while maintaining the biological system's fundamental structure
Solution Approach 2:
The patent segments the HdrABC enzyme complex into individual subunits (HdrA, HdrB, HdrC) and targets specific mutations to the HdrB subunit. This segmentation allows precise modification of the catalytic center without disrupting the entire complex, enabling targeted improvement of methane production while maintaining overall enzyme functionality
2Productivity
If genetically engineered strains are developed to increase production rate, then productivity improves, but the genetic tractability remains a limitation
Solution Approach 1:
The patent overcomes genetic tractability limitations by making precise parameter changes to the HdrABC gene sequence. By introducing specific point mutations (M249V, and mutations at positions 250-251 in HdrB) into the hdrABC operon, the patent achieves enhanced methane production without requiring complex genetic restructuring, thereby improving ease of manufacture through targeted sequence modification
Solution Approach 2:
The patent uses copying by introducing the mutated hdrABC operon into the Methanosarcina acetivorans genome. The engineered gene copy replaces or supplements the wild-type copy, allowing the beneficial mutations to be propagated through the organism's reproduction while maintaining the original genomic context and reducing engineering complexity
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 engineered strain, NB105, demonstrates a 28.9% increase in methane production rate compared to the parent strain, overcoming the limitations of slow production rates and genetic tractability in methanogenic microbes.
Implementation Method 1
The HdrABC enzyme complex is essential for growth of M. acetivorans on methanol or acetate and for production of methane from these substrates
Data Source
AI summary
Microbial strains are provided, as are methods of making and using such microbial strains.