Bacillus Purine Production via Fructose Bisphosphatase Disruption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing purine-derived substances like inosine and guanosine through fermentation using Bacillus bacteria are limited by the relationship between fructose bisphosphatase activity and biosynthetic pathways, with no reports on reducing fructose bisphosphatase activity to enhance production.
Innovation Solution
A Bacillus bacterium is modified to decrease fructose bisphosphatase activity, increase phosphoribosyl pyrophosphate synthetase activity, and alter purine operon expression by disrupting specific genes, such as fructose bisphosphatase and purR genes, to improve the production of purine nucleosides and nucleotides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fructose bisphosphatase activity is maintained at normal levels in Bacillus bacteria, then the bacteria can perform normal glyconeogenesis, but the production of purine-derived substances is limited
Solution Approach 1:
The patent extracts and removes the fructose bisphosphatase enzyme from the bacterial metabolic system by disrupting the fbp gene. This extraction eliminates the enzyme's function of converting fructose-1,6-bisphosphate to fructose-6-phosphate, thereby redirecting metabolic flux toward purine nucleoside production without the need for complex regulatory systems
Solution Approach 2:
The patent changes the key parameter of fructose bisphosphatase activity from normal levels to decreased levels through genetic modification. By disrupting the fbp gene, the enzyme activity parameter is reduced, which fundamentally alters the metabolic pathway distribution and enhances purine-derived substance production
2Productivity
If multiple gene disruptions are performed to optimize purine production, then production efficiency increases, but the difficulty of strain development increases
Solution Approach 1:
The patent segments the strain development process into distinct genetic modification steps: first disrupting the fbp gene to reduce fructose bisphosphatase activity, then disrupting the purR gene to enhance purine operon expression, and optionally disrupting the deoD gene to prevent inosine degradation. This segmentation allows systematic optimization while maintaining clear tracking of each modification's contribution to final yield
Solution Approach 2:
The patent performs preliminary genetic modifications to establish the metabolic foundation before final strain selection. By pre-disrupting the fbp and purR genes, the patent creates a metabolic framework that naturally favors purine nucleoside accumulation, simplifying subsequent strain development and selection processes
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 modified bacterium effectively increases the production of purine nucleosides and nucleotides, such as inosine, xanthosine, and guanosine, by optimizing enzymatic activities and gene expression, leading to enhanced fermentation yields.
Implementation Method 1
Methods for producing inosine and guanosine by fermentation using adenine auxotrophic strains of Bacillus bacteria have been reported
Data Source
AI summary
A purine-derived substance is produced by culturing a bacterium belonging to the genus Bacillus which is able to produce purine-derived substance and has been modified so that enzymatic activity of fructose bisphosphatase is decreased, and collecting the purine-derived substance from the medium or cells.