Recombinant Host Cells for D-Lactic Acid Production
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Solution Overview
Problem
Current methods for producing high-purity D-lactic acid through microbial fermentation are inefficient at commercial scales due to low yields, high costs, and byproduct formation, limiting its application in biodegradable plastics and other industries.
Innovation Solution
Development of recombinant cells with heterologous nucleic acids encoding D-lactate dehydrogenase and other proteins, along with genetic disruptions in genes like pyruvate decarboxylase and NAD(P)H dehydrogenase, to enhance D-lactic acid production and reduce byproduct formation, using a biosynthetic process that utilizes renewable carbon sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing bacterial fermentation methods are used to produce D-lactic acid, then D-lactic acid can be manufactured, but the yields are low and production costs are high
Solution Approach 1:
The patent applies parameter changes by modifying fermentation conditions including pH control (maintaining pH 4.0-6.0), temperature optimization (30-37°C), and dissolved oxygen control (20-80% saturation) to maximize D-lactic acid yield while reducing production costs through efficient process parameters
2Manufacturing precision
If existing microbial fermentation methods are used, then D-lactic acid production is possible, but byproduct formation occurs and purity is reduced
Solution Approach 1:
The patent applies the extraction principle by removing harmful byproducts through specific purification steps including centrifugation, filtration, and ion exchange chromatography to isolate high-purity D-lactic acid from the fermentation broth, eliminating contaminants and byproducts
Solution Approach 2:
The patent converts the harmful effect of byproduct formation into a benefit by using the byproducts as indicators to optimize fermentation conditions, and by utilizing waste heat from the fermentation process for preheating incoming media, thereby improving overall process efficiency
3Productivity
If complex and expensive nutrients are used in fermentation media, then microbial growth is supported, but production costs increase and commercial scale application is prohibited
Solution Approach 1:
The patent applies this principle by using inexpensive, readily available nutrients in the fermentation media such as yeast extract, peptone, and glucose, replacing complex and expensive defined media components while maintaining high fermentation efficiency and enabling commercial scale production
4Manufacturing precision
If engineered host cells are used in Saccharomyces cerevisiae, then D-lactic acid production is attempted, but the cells cannot grow leading to low yields
Solution Approach 1:
The patent resolves the contradiction by optimizing fermentation parameters including maintaining pH 4.0-6.0, temperature 30-37°C, and dissolved oxygen 20-80% saturation, which allows engineered S. cerevisiae cells to both grow and produce D-lactic acid at high yields
Solution Approach 2:
The patent applies dynamics by using a two-stage fermentation process where the first stage optimizes for cell growth and the second stage optimizes for D-lactic acid production, allowing the system to adapt to different operational requirements and achieve both high cell density and high product yield
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 approach enables high-yield, high-purity D-lactic acid production with reduced byproduct formation, making it suitable for commercial applications in biodegradable plastics and other industries, and aligns with the need for sustainable, renewable chemical alternatives to petrochemicals.
Implementation Method 1
recombinant cells with heterologous nucleic acids encoding D-lactate dehydrogenase
Implementation Method 2
production of D-lactic acid by direct fermentation from carbon sources
Data Source
AI summary
Methods and materials related to producing D-lactic acid are disclosed. Specifically, isolated synthetic or natural nucleic acids, synthetic or natural polypeptides, host cells, and methods and materials for producing D-lactic acid by direct fermentation from carbon sources are disclosed, along with methods of preparing D-lactic acid polymers.