Method and device for producing 1,3-propylene glycol by utilizing microbial conversion

Abstract

The invention relates to a method for producing 1,3-propylene glycol by utilizing microbial conversion. The method comprises the following steps: (1) performing micro-aerobic culture, thereby acquiring a fermented culture solution; (2) performing anaerobic fermentation, discharging 10%-20% of fermentation liquor into a microfiltration system when the conductivity is above 14mS / cm, guiding the microfiltration liquid into an electrodialysis system, and flowing back to a fermentation tank when the conductivity is 2-9mS / cm; (3) ending the microfiltration, backwashing a micro-filtration membrane with a culture medium of which the volume is 1%-3% of the volume of the fermentation liquor and then injecting into the fermentation tank; and (4) discharging the fermentation liquor of which the volume is 60%-80% of the volume of the fermenting tank into the microfiltration system when the concentration of 1,3-propylene glycol in the fermentation liquor is above 90g / L, guiding the microfiltration liquid into the electrodialysis system, reducing the conductivity to 0.1mS / cm, recovering the clear liquid, adding the culture medium of which the volume is 50%-80% of the volume of the original fermentation liquor and fermenting for the next time. The continuous fermentation system according to the invention can prolong the fermentation stable period and maintain higher production strength by reducing the inhibiting effect of the byproduct of the system.

Description

technical field [0001] The invention belongs to the technical field of bioengineering, and in particular relates to a method and a device for producing 1,3-propanediol by transforming microorganisms. Background technique [0002] 1,3-Propanediol is an important chemical raw material and pharmaceutical intermediate, which is widely used in the production of polyester fibers and the manufacture of polyurethane and cyclic compounds. In recent years, 1,3-propanediol, as an important raw material and intermediate in organic synthesis, has become a research hotspot because of its unique properties and wide application. [0003] There are three main production methods of 1,3-propanediol: acrolein hydration hydrogenation method, ethylene oxide carbonylation method and microbial transformation method. Although the microbial transformation method started earlier, it did not gradually attract people's attention until the 1980s. Although the current main method is still the chemical m...

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Problems solved by technology

It can be seen from the examples that although this method can improve the utilization rate of the bacteria to glycerin, increase the concentration of 1,3-propanediol and the production intensity, the by-products also increase significantly

CN1955304A discloses a method for microorganisms to produce 1,3-propanediol by anaerobic fermentation of glycerol. In this method, an appropriate amount of polyacid is added to the fermentation medium or in the exponential phase of bacterial growth, and the polyacid can strengthen the metabolic process. Metabolic process after pyruvate is generated, but this method cannot effectively reduce the generation of by-products, because the added polybasic acid cannot regulate the generation of pyruvate, and pyruvate is the source of various by-products, the metabolism of Pyruvate breaks down completely

Although adding a reducing agent to the medium theoretically helps the conversion of glycerol to 1,3-propanediol, but in the entire metabolic pathway, the intervention of a large number of reducing equivalents will promote many side reactions, such as the conversion of pyruvate to lactic acid, phosphoric acid The conversion of enolpyruvate to succinic acid, the conversion of acetyl CoA to ethanol, etc., so the addition of reducing agent will lead to the formation of a large number of by-products

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