3results about How to "Improve acid production efficiency" patented technology

The present invention discloses an efficient immobilized propionic acid continuous fermentation system, and relates to the technical field of microbial fermentation, the system comprises: a fermentation tank main body, in which propionibacterium immobilization units containing porous ceramic carriers and chitosan alginic acid composite anchoring layers are detachably and circumferentially distributed; the material supplementing unit is connected with the tank top and comprises a raw material storage tank, a pretreatment cavity, a filter screen, a buffer cavity and a flow metering pump; the circulating pipeline is connected with two ends of the tank, is provided with a circulating pump and is internally provided with a membrane separation unit of an ultrafiltration membrane assembly; the temperature control unit consists of a jacket outside the tank and a temperature sensor inside the tank; the pH adjusting unit comprises an acid-base storage tank, a metering pump and an in-tank pH sensor; the tank is internally connected with an aeration unit of an external air source, and the bottom of the tank is provided with a blow-off unit of a blow-off pipeline with a stop valve; by constructing the propionibacterium immobilization unit combining the porous ceramic carrier and the chitosan alginic acid composite anchoring layer, the problems of low cell density and easy loss of strains in traditional propionic acid fermentation are effectively solved.

The application discloses a sludge anaerobic acid production strengthening method based on synergistic degradation of melanoid-like substances by thermal hydrolysis and potassium permanganate, which comprises the following steps: (1) screening and removing impurities from sludge, and then performing gravity sedimentation and concentration; (2) thermal hydrolysis treatment: high-temperature and high-pressure treatment, pressure relief and cooling; (3) adding potassium permanganate for oxidation, and combining with ultrasonic dispersion; (4) anaerobic fermentation: inoculating active sludge, and controlling fermentation conditions; and (5) separating and extracting short-chain fatty acids. The application realizes the synergistic effect of thermal hydrolysis and potassium permanganate, targets the degradation of melanoid-like substances generated in the thermal hydrolysis process, eliminates the inhibition of the melanoid-like substances on anaerobic microorganisms, and promotes the efficient dissolution of organic matters in sludge. The nano manganese dioxide generated by potassium permanganate oxidation serves as an electron transfer medium, further strengthens the metabolic activity of acid-producing bacteria, and the pickling recovery rate is greater than or equal to 90%. The method makes the yield of short-chain fatty acids increase by 65% (up to 456 mg / g VS), has high efficiency and environmental protection, and provides an innovative solution for sludge resource treatment.

This invention provides an L-homoserine-producing strain, its construction method, and its applications. The strain does not contain plasmids. E.coli W3110, as a chassis strain, had the relA and thrB genes knocked out, and heterologously expressed genes derived from... Clostridium acetobutylicum The gapC gene and the aspB gene derived from Bacillus subtilis were overexpressed, along with ppc, asd, and thrA. fbr ,rhtA,pntAB,spoT fbr Genes; the strain described above can effectively improve the L-homoserine synthesis efficiency by knocking out genes of the L-homoserine degradation pathway, enhancing the expression of key enzymes in the pathway, optimizing the L-homoserine transport system, increasing the reducing power NADPH content, and enhancing the ability to withstand amino acid starvation. It is genetically stable, requires no addition of resistance substances, has high acid production efficiency, and has good L-homoserine synthesis capacity.