Recombinant Bacillus subtilis ribozyme regulation acetylglucosamine
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Solution Overview
Problem
Current methods for producing acetylglucosamine (GlcNAc) in Bacillus subtilis result in low titers due to metabolic imbalances and toxic intermediates, limiting industrial application.
Innovation Solution
The use of the glmS ribozyme and its mutant to dynamically regulate the expression of glmM, pfkA, and pgi genes in recombinant Bacillus subtilis, enhancing GlcNAc production by integrating these genes into the genome and employing feedback regulation to fine-tune expression based on GlcN6P concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If static control of gene expression is used in metabolic engineering, then the system is simple to construct, but GlcNAc titer is limited due to toxic intermediates and metabolic imbalances
Solution Approach 1:
The patent applies dynamics by replacing static gene expression control with a dynamic ribozyme-based system. The glmS ribozyme dynamically responds to intracellular GlcN6P concentrations, automatically adjusting the expression levels of pfkA, glmM, and pgi genes in real-time according to metabolic needs, thereby resolving the contradiction between system simplicity and high GlcNAc titer production
Solution Approach 2:
The patent implements feedback control through the glmS ribozyme, which senses intracellular GlcN6P levels and uses this information to regulate its own cleavage activity and consequently control the expression of target genes. This feedback mechanism prevents toxic intermediate accumulation and maintains metabolic balance while maximizing GlcNAc production
2Productivity
If GlcNAc production is increased through metabolic engineering, then yield improves, but toxic intermediates accumulate causing metabolic imbalances
Solution Approach 1:
The glmS ribozyme provides real-time feedback on intracellular GlcN6P concentrations, automatically adjusting gene expression to prevent toxic intermediate accumulation while maintaining high GlcNAc production rates
Solution Approach 2:
The patent changes the regulatory parameter from static constitutive expression to dynamic ribozyme-mediated expression that responds to metabolic parameters (GlcN6P concentration), enabling the system to adapt and prevent toxic intermediate buildup
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 GlcNAc titer by 63.9% to 20.05 g/L, improving metabolic flux and reducing toxic intermediates, and can be applied to other industrial microbes for chemical production.
Implementation Method 1
The glmS ribozyme can cleave the messenger RNA of the glmS gene in Gram-positive bacteria. It is activated by glucosamine-6-phosphate (GlcN6P) which is the metabolic product of the GlmS enzyme to stimulate autocatalytic site-specific cleavage.
Data Source
AI summary
The invention discloses a method for improving the yield of Bacillus subtilis acetylglucosamine, which belongs to the technical field of genetic engineering. In the invention, the recombinant Bacillus subtilis S5 (S5-PxylA-glmS-P43-GNA1) is taken as a starting strain, and the glmS ribozyme is integrated into the mid of rbs and the promoter sequence of the glmM and pfkA gene, respectively. The ribozyme mutant has the advantage of prolonging the stability of the mRNA and integrated into the mid of rbs and the promoter sequence of the pgi gene. The yield of GlcNAc of the recombinant strain reaches 11.79-20.05 g/L. This laid the foundation for the further metabolic engineering of Bacillus subtilis to produce GlcNAc.