Two-Step Fermentation for 1,3-Propanediol from Raw Starch
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Solution Overview
Problem
Current methods for producing 1,3-propanediol and 2,3-butanediol from starch materials face challenges such as high production costs due to low concentrations and yields, primarily because they rely on glycerol as substrates and require complex technical conditions.
Innovation Solution
A two-step fermentation method using Candida krusei or Hansenula Arabitolgens for initial starch saccharification followed by Klebsiella, Clostridium butyricum, or Clostridium pasteurianum fermentation, employing aerobic and anaerobic conditions to enhance product concentrations and yields, with cell recovery for efficient seed culturing and glycerin utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional chemical synthesis methods are used to produce 1,3-propanediol, then production capacity can be maintained, but excessive by-products are generated and selectivity is poor
Solution Approach 1:
The patent replaces chemical synthesis methods with biological fermentation methods using microorganisms (Klebsiella pneumoniae, Clostridium butyricum, or Clostridium pasteurianum) to convert glucose or glycerol into 1,3-propanediol. This substitution of chemical processes with biological systems achieves high selectivity (80-90% conversion efficiency) while maintaining production capacity, eliminating the by-product issues inherent in chemical synthesis.
2Productivity
If chemical synthesis methods are used, then production capacity can be maintained, but high temperature and pressure conditions are required
Solution Approach 1:
The patent fundamentally changes the operating parameters from high temperature and pressure (chemical synthesis) to mild conditions (fermentation). The fermentation process operates at temperatures of 25-40°C and atmospheric pressure, using microorganisms to catalyze the conversion. This parameter change maintains productivity while eliminating the need for expensive high-temperature and high-pressure equipment.
3Quantity of substance
If conventional fermentation methods using glycerol as substrate are used, then 1,3-propanediol can be produced, but production costs are high due to low concentrations and yields
Solution Approach 1:
The patent changes the substrate from glycerol to glucose obtained from starch hydrolysis. This parameter change increases both the concentration of 1,3-propanediol in the fermentation broth and the overall yield. Glucose is a cheaper and more readily available substrate from starch materials, which directly reduces production costs while improving product concentration.
Solution Approach 2:
The patent introduces a preliminary starch hydrolysis step before fermentation to convert starch into glucose. This preliminary action prepares the substrate in a form that is more efficient for fermentation, enabling higher 1,3-propanediol concentrations and yields. The hydrolyzed glucose serves as an optimal carbon source for the microorganisms, improving overall process efficiency and reducing costs.
4Adaptability or versatility
If starch materials are used as raw material, then renewable resources are utilized, but complex technical conditions and low yields are encountered
Solution Approach 1:
The patent segments the production process into two distinct stages: (1) starch hydrolysis to glucose, and (2) fermentation to 1,3-propanediol. This segmentation allows optimization of each stage independently, ensuring efficient conversion at each step. The clear separation of steps eliminates the complexity and low yields associated with attempting single-step conversion, while maintaining the advantage of using renewable starch materials.
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 method significantly increases the concentration and yield of 1,3-propanediol and 2,3-butanediol, reducing production costs and improving the availability of raw materials, achieving glycerin concentrations of 158-179 g/L and 1,3-propanediol concentrations of 66-72 g/L, while maintaining high cell viability for multiple batch cycles.
Implementation Method 1
Candida krusei or Hansenula Arabitolgens are inoculated into a fermentation medium with the saccharifying liquid of raw starches as a carbon source, using an aerobic condition in earlier stage and an anaerobic condition in later stage
Implementation Method 2
Klebsiella, Clostridium butyricum, or Clostridium pasteurianum are inoculated into a fermentation medium in which the glycerin fermentation broth obtained from step 1) serves as a carbon source. The bacteria are fermented anaerobically for 30-32 hours, and then fermented aerobically when the production rate of 1,3-propanediol decreased obviously
Data Source
AI summary
The invention discloses a method for producing 1,3-propanediol and 2,3-butanediol from raw starch materials, including the following steps: 1) Candida krusei or Hansenula Arabitolgens Fang are inoculated into a fermentation medium with the saccharifying liquid of the raw starches as a carbon source; the yeast cells are cultured on an aerobic condition until glucose-consuming-rate is significantly reduced, and then fermented anaerobically to a glucose concentration from 5 to 10 g/L; the fermentation broth is collected and filtered to remove the yeast cells in the broth, and the resultant filtrate is glycerin fermentation broth; 2) Klebsiella, Clostridium butyricum, or Clostridium pasteurianum are inoculated into a fermentation medium in which the glycerin fermentation broth obtained from step 1) serves as a carbon source; the bacteria are fermented anaerobically for 30-32 hours, and then fermented aerobically when the production rate of 1,3-propanediol decreased obviously, and the fermentation was stopped when the concentration of glycerin is reduced to a level below 10 g/L, and finally 1,3-propanediol and 2,3-butanediol are obtained. The method of the present invention can effectively reduce production cost and increase productivity.