Recombinant Lactobacillus rhamnosus for High Purity L-Lactic Acid
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Solution Overview
Problem
Current microbial fermentation methods for producing L-lactic acid face challenges with low yield and optical purity, high production costs, and environmental concerns, limiting the efficiency and effectiveness of industrial applications.
Innovation Solution
A recombinant strain of Lactobacillus rhamnosus is genetically modified to weaken D-lactate dehydrogenase activity and enhance L-lactate dehydrogenase activity, resulting in improved L-lactic acid yield and optical purity, reduced fermentation costs, and enhanced environmental friendliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chemical synthesis method is used to produce L-lactic acid, then production cost is reduced, but optical purity decreases and environmental pollution increases
Solution Approach 1:
The patent changes the biological parameters of the producing organism by modifying enzyme activities (reducing D-lactate dehydrogenase activity to below 10 U/mL and increasing L-lactate dehydrogenase activity to above 50 U/mL), which transforms the fermentation process to achieve high optical purity (above 98%) while maintaining cost-effectiveness through efficient metabolic pathways
2Manufacturing precision
If conventional microbial fermentation is used to produce L-lactic acid, then optical purity is improved, but yield and productivity remain low
Solution Approach 1:
The patent optimizes key metabolic parameters by controlling enzyme activities: reducing D-lactate dehydrogenase activity to below 10 U/mL and increasing L-lactate dehydrogenase activity to above 50 U/mL. This parameter optimization redirects metabolic flux toward L-lactic acid production, achieving both high optical purity (above 98%) and high yield (above 90% conversion rate)
Solution Approach 2:
The patent implements metabolic feedback control by monitoring and adjusting enzyme activities in the fermentation process. The modified strain exhibits enhanced L-lactate dehydrogenase activity that provides positive feedback for L-lactic acid production, while suppressed D-lactate dehydrogenase activity prevents formation of competing D-lactic acid, thereby simultaneously improving yield and optical purity
3Device complexity
If existing lactic acid bacteria strains are used, then production process is simple, but L-lactic acid yield and optical purity cannot meet practical demands
Solution Approach 1:
The patent modifies specific biochemical parameters of Lactobacillus rhamnosus by controlling enzyme activities: D-lactate dehydrogenase activity is reduced to below 10 U/mL and L-lactate dehydrogenase activity is increased to above 50 U/mL. This targeted parameter modification achieves high optical purity (above 98%) without complicating the overall production process, maintaining microbial fermentation simplicity
4Device complexity
If existing lactic acid bacteria strains are used, then production process is simple, but yield and biomass are insufficient
Solution Approach 1:
The patent optimizes metabolic parameters by adjusting enzyme activities: reducing D-lactate dehydrogenase to below 10 U/mL and enhancing L-lactate dehydrogenase to above 50 U/mL. This parameter optimization improves L-lactic acid yield to above 90% conversion rate while maintaining simple microbial fermentation processes without requiring complex production systems
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 strain achieves high L-lactic acid yield and optical purity, shortening production time, reducing energy consumption, and minimizing contamination, while being environmentally friendly.
Implementation Method 1
the microbial fermentation method for producing L-lactic acid by using renewable resources (e.g., glucose) as raw materials
Implementation Method 2
the activity of L-lactate dehydrogenase is enhanced
Data Source
AI summary
The present disclosure relates to the technical fields of genetic engineering and microbial fermentation, and discloses a recombinant strain for producing L-lactic acid, wherein the recombinant strain is obtained by genetically modifying a starting strain, the activity of D-lactate dehydrogenase of the recombinant strain is weakened or inactivated, and the activity of L-lactate dehydrogenase is enhanced, as compared with the starting strain. The present invention can significantly improve the fermentation effect, the yield of the L-lactic acid and the optical purity of the product L-lactic acid.