275 results about "Staphylococcus lactis" patented technology

The invention belongs to the technical field of functional microorganism screening and application, and particularly relates to a strain with a purine reducing function and application thereof. The lactococcus lactis AMCC 11671 (Lactococcus lactis AMCC 11671) provided by the invention is preserved in the China Center for Type Culture Collection (CCTCC), and the preservation number of the lactococcus lactis AMCC 11671 is CCTCC NO: M 2024078. The lactococcus lactis AMCC 11671 provided by the invention has good crude enzyme activity, can effectively slow down the generation and accumulation of uric acid by reducing the purine content and degrading uric acid, has good tolerance to acid and cholate, has the ability to tolerate gastrointestinal tract environment, and has potential of colonization in human gastrointestinal tracts and play roles.

The invention belongs to the field of fermentation, and particularly relates to a complex microbial inoculant, original cheese, processed cheese with a blood sugar reducing function and preparation and application of the complex microbial inoculant. Wherein the processed cheese is prepared by the method comprising the following steps: mixing the components including raw cheese, sugarcane juice, corn oil, casein, concentrated milk protein, blueberry powder, mono / diglycerol fatty acid ester, sodium citrate, sodium tripolyphosphate, sodium hexametaphosphate, salt guar gum, potassium sorbate and water, and then emulsifying to obtain the processed cheese, the sugar cane juice, the corn oil, the casein, the concentrated milk protein, the blueberry powder, the mono / diglycerol fatty acid ester, the sodium citrate, the sodium tripolyphosphate, the sodium hexametaphosphate, the salt guar gum, the potassium sorbate and the water, the original cheese is prepared from a complex microbial inoculant, and the complex microbial inoculant comprises lactococcus lactis bacterial powder, lactococcus lactis subsp. Lactis bacterial powder, lactobacillus delbrueckii subsp. Lactis bacterial powder, lactobacillus plantarum bacterial powder and lactobacillus paracasei bacterial powder. The processed cheese provided by the invention has a better function of controlling blood sugar, and meanwhile, the processed cheese is fine and uniform in texture and has good smearing performance.

The invention relates to the technical field of microbial fermentation, in particular to a preparation method of a glucose fermentation product with bacteriostatic activity, which comprises the following steps: (1) inoculating a lactococcus lactis subsp. Lactis seed solution into a glucose-containing fermentation culture solution, and fermenting to obtain a first fermentation solution; (2) inoculating a pediococcus acidilactici seed solution into the first fermentation liquor, supplementing glucose, and fermenting to obtain second fermentation liquor; and (3) adjusting the pH value of the second fermentation liquor to be acidic, filtering, concentrating, and spray-drying to obtain the glucose fermentation product. According to the invention, the characteristic that organic acids and bacteriocin generated by lactococcus lactis subsp. Lactis and pediococcus acidilactici are different in types is fully utilized, metabolites of the two bacteria are obtained at the same time by adopting a sequential sequence type fermentation mode, and the metabolites of the lactococcus lactis subsp. Lactis are converted by pediococcus acidilactici, so that a new substance with bacteriostatic activity is obtained; the antibacterial activity is improved. Meanwhile, the problem of nutrition competition caused by mixed culture of the two bacteria is avoided, and the fermentation efficiency is improved.

The invention relates to the technical field of microorganisms, and particularly discloses a nitrogen-fixing and cadmium-reducing microbial agent as well as a preparation method and application thereof. The microbial agent consists of bacillus pseudomycoides, lactococcus lactis, azotobacter chroococcum and biochar, wherein the biochar is obtained by pyrolyzing and carbonizing rice straws. The bacillus pseudomycoides can reduce the bio-availability of soil cadmium; lactococcus lactis can secrete a large number of biological active substances such as exopolysaccharides and enzymes, and the activity of other microorganisms is stimulated and improved; azotobacter chroococcum converts nitrogen in air into ammonium, amino acid and peptide which can be utilized by plants and promotes plant growth, and released metallothionein contains free sulfydryl which is combined with Cd ions, so that a stable sulfide compound is formed. The biological carbon adsorbs and fixes the three bacteria, so that the microorganisms can continuously and effectively play a role and have a mutual synergistic effect, the fixation of Cd in the soil is further enhanced, the availability of nitrogen is improved, and the plant growth is effectively promoted.

The invention relates to the technical field of microorganisms, in particular to lactococcus lactis subsp. Lactis JYLL-51 for improving sarcopenia obesity as well as a microbial agent and application of the lactococcus lactis subsp. Lactis JYLL-51. The Lactococcus lactis subsp. Lactis JYLL-51 is preserved in China General Microbiological Culture Collection Center (CGMCC) on March 13, 2024, the preservation address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the preservation number is CGMCC NO.30016. The Lactococcus lactis subsp. Lactis JYLL-51 has the advantages that the Lactococcus lactis subsp. Lactis JYLL-51 can be used for preparing the Lactococcus lactis subsp. Lactis JYLL-51; the invention provides a lactococcus lactis subsp. Lactis JYLL-51, and experiments show that the lactococcus lactis subsp. Lactis JYLL-51 microbial inoculum prepared from the strain can not only improve the weight and strength of skeletal muscle, but also reduce fat accumulation induced by high fat, and can significantly improve sarcopenia obesity.

The invention belongs to the technical field of microorganism mutation breeding, and particularly relates to a nisin high-yield mutant strain with enhanced production performance. The mutant strain is specifically lactococcus lactis 2686, and the preservation number of the mutant strain is CCTCC (China Center for Type Culture Collection) NO: M 2023219. The strain has relatively high osmotic pressure tolerance, can still normally grow and produce nisin when the osmotic pressure is higher than 0.66 osM / kg H2O, meanwhile, the strain has excellent nisin production capacity, the titer reaches 9834 IU / mL when the strain is fermented in a shake flask for 21 hours, and the titer reaches 21000 IU / mL when the strain is fermented in a fermentation tank for 22 hours. The method is high in yield, good in stability, low in production cost and suitable for further industrial application.

The invention relates to the field of microorganisms, and discloses a Lactococcus lactis subsp. Lactis VB346 which is preserved in the China Center for Type Culture Collection on September 20, 2024, and the preservation number is CCTCC NO: M 20242013. The invention further discloses a preparation method of the Lactococcus lactis subsp. Lactis VB346. The lactococcus lactis subsp. Lactis VB346 disclosed by the invention has the capability of efficiently degrading purine nucleoside, and can decompose purine nucleoside in ingested food in intestinal tracts, so that the absorption amount of purine nucleoside by small intestines is reduced. The polypeptide has the ability of degrading bilirubin, and can be used for treating or improving hyperbilirubinemia, or improving liver and gall injury caused by hyperbilirubin; meanwhile, the acid resistance required by survival in the stomach, the cholate tolerance required by survival in the intestinal tract and the stable survival ability in the intestinal tract are achieved, and the bacillus subtilis has huge application prospects in preparation of drugs, microbial agents, health care products or food.

The invention belongs to the technical field of biological medicine, and discloses lactococcus lactis HX21473 and application thereof, the lactococcus lactis HX21473 is preserved in China General Microbiological Culture Collection Center (CGMCC) on January 20, 2025, and the preservation number is CGMCC NO.33476. The invention further discloses a preparation method of the lactococcus lactis HX21473. The invention provides a strain of lactococcus lactis HX21473 capable of efficiently expressing a foreign protein. The lactococcus lactis HX21473 has strong acid resistance, can be used as an oral vaccine live carrier, and promotes research, development and application of oral vaccines.

The present disclosure relates to a Lactococcus lactis subsp. lactis CAB701 strain having both anti-obesity and immune-promoting activities, an anti-obesity or immune-enhancing food composition containing the same, and an anti-obesity or immune-enhancing vegan fermented milk containing the same. The CAB701 strain of the present disclosure has pancreatic lipase inhibitory activity and can be widely utilized for preventing, ameliorating or treating obesity and for enhancing immunity. Furthermore, it can be used as a starter for fermentation. In addition, since a vegan fermented milk prepared with the CAB701 strain of the present disclosure exhibits a significantly slower decrease in the viable Lactobacillus cell count during the storage period as compared to vegan fermented milks prepared with conventional strains, it can be seen that the CAB701 strain of the present disclosure is useful in the preparation of a vegan fermented milk.

Provided are methods, prokaryotic host cells, expression vectors, and kits for the production of psilocybin derivatives produced using at least one psilocybin production gene. The methods enable production of psilocybin derivatives and related compounds including non-naturally occurring species. In certain embodiments, a prokaryotic host cell is selected from the group consisting of from the group consisting of Escherichia coli, Corynebacterium glutamicum, Vibrio natriegens, Bacillus subtilis, Bacillus megaterium, Escherichia coli Nissle 1917, Clostridium acetobutlyicum, Streptomyces coelicolor, Lactococcus lactis, Pseudomonas putida, Streptomyces clavuligerus, and Streptomyces venezuelae.

The invention belongs to the technical field of new energy materials, and particularly relates to a preparation method of a bamboo-based hard carbon sodium ion battery negative electrode material, which specifically comprises the following steps: (1) slicing, crushing, screening, sieving, drying and treating fresh bamboo under steam pressure to obtain bamboo powder; (2) bamboo powder and lactococcus lactis liquid are mixed and fermented, and after fermentation is completed, the bamboo powder and the lactococcus lactis liquid are washed to be neutral and dried; (3) placing the bamboo powder subjected to fermentation treatment in an inert atmosphere, heating, keeping constant temperature, and cooling to obtain a pre-carbonized sample; (4) soaking the pre-carbonized sample in a hydrochloric acid solution, continuously reacting, washing to be neutral, and drying; and (5) continuously heating the acid-washed and dried material in the step (4) in the inert atmosphere, carbonizing at a constant temperature, and cooling to obtain the final sodium-ion battery negative electrode material. The method disclosed by the invention has the advantages of remarkable environmental friendliness, low cost, simplicity and convenience in operation and the like; and the battery negative electrode material prepared by the method disclosed by the invention has excellent electrochemical performance.

The invention belongs to the technical field of aquaculture, and particularly relates to a pearl grouper fry rearing method. According to the method, firstly, after the roes are hatched, the fries are soaked with a bactericide, harmful bacteria on the surfaces of the roes and in a hatching pond can be effectively killed, and a bacteria solution of lactobacillus brevis serves as the bactericide, so that the use of antibiotics is reduced while the growth of pathogenic bacteria is inhibited; the culture pond is divided into 1m * 1m spaces by the partition plates, so that the phenomenon that the fries kill each other or snatch for food due to insufficient spaces is avoided, and uniform growth of the fries is facilitated; culture is carried out in stages according to nutritional requirements of different growth stages, and the Weissella microbial inoculum and the lactococcus lactis microbial inoculum are added to the feed in each stage, so that the intestinal microecological balance of the fry is adjusted, the growth and reproduction of harmful bacteria are inhibited, the intestinal digestion and absorption functions of the fry are enhanced, and the utilization rate of the feed is increased.

The invention belongs to the field of microorganisms, and particularly relates to lactococcus lactis Jlus 880314 and application thereof. The strain is classified and named as Lactococcus lactis, and is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing; the preservation number of the strain is CGMCC No. 33961. Time-of-flight mass spectrometry analysis shows that nisin exists in a metabolite of the strain, and the strain can be used for producing nisin. The compound shows an excellent and wide antibacterial function in antibacterial experiments, can be used for preparing antibacterial drugs, particularly has a remarkable inhibiting effect on growth of gram-negative bacteria and fungi, can be used for preparing drugs for relieving or treating enteritis, or preparing drugs, nourishment or health care products for regulating gastrointestinal tract micro-ecological balance of people or animals, and can be used for preparing medicines for relieving or treating enteritis. The compound can also be used for preparing antibacterial food additives and / or animal feed additives. A hemolysis experiment result shows that hemolysis is avoided, toxic and side effects are small, and wide development prospects and application values are achieved.

The invention discloses yoghurt oil with fruity flavor and a preparation method of the yoghurt oil, and belongs to the technical field of yoghurt oil processing. The Lactococcus lactis SITRS-0011 provided by the invention can be independently used as a leavening agent, when the Lactococcus lactis SITRS-0011 is used for fermenting yoghurt oil, the titration acidity can reach 83.21 DEG T, the yoghurt oil contains 2, 3-butanedione (1180 [mu] g / kg), acetoin (2092 [mu] g / kg), lactones (623 [mu] g / kg), 3-methylbutyraldehyde (117 [mu] g / kg), phenethyl alcohol (1863 [mu] g / kg), phenylacetaldehyde (336 [mu] g / kg) and other substances, and the Lactococcus lactis SITRS-0011 is rich in milk flavor, has flower fragrance and nut flavor, is unique in flavor, and can be used for preparing the and the overall sensory score is high.

The invention discloses a lactococcus lactis strain with high nisin yield and application, and belongs to the technical field of industrial microorganisms. According to the invention, a nisin-tolerant nisin high-producing strain (Lactococcus lactis MN6) is successfully bred on the basis of compound mutation of ethyl methane sulfonate and heavy ion beam and in combination with nisin resistance screening, the strain can tolerate a fermentation environment with the nisin concentration of 6000 IU. ML <-1 >, the nisin yield through shake flask horizontal fermentation can reach 10776 IU. ML <-1 >, which is 9.76 times of the shake flask fermentation yield of original bacteria, the strain has good passage stability, and the strain can be used for producing a high-yield strain of nisin. The method is more suitable for industrial production.

The invention relates to a polygonatum sibiricum probiotic compound preparation with an aging delaying effect and application thereof. The compound preparation comprises a polygonatum sibiricum extract and a probiotic composition, the bacterial strains in the probiotic composition comprise a combination of a bifidobacterium animalis subsp. Lactis BLa36 bacterial strain, a bifidobacterium longum BL21 bacterial strain, a bifidobacterium adolescentis BAC30 bacterial strain, a lactobacillus plantarum Lp90 bacterial strain, a lactobacillus casei LC89 bacterial strain, a bifidobacterium breve BBr60 bacterial strain and a pediococcus acidilactici CCFM7902 bacterial strain. After the rhizoma polygonati component and the probiotic component are combined for use, the rhizoma polygonati component and the probiotic component have potential synergistic effects in the aspects of improving the intestinal flora structure, regulating the intestinal environment, delaying senescence, reducing inflammation-related symptoms and the like. Moreover, further, various probiotic strains are compounded and combined for use, so that the capability of a related compound preparation in the aspect of delaying various symptoms of senescence can also be improved in a combined manner.

The invention discloses a lactococcus lactis recombinant bacterium for expressing cyclic diadenylate and application of the lactococcus lactis recombinant bacterium. Homologous DAC is introduced into lactococcus lactis NZ9000, PDE is knocked out to improve expression of cyclic diadenylate in lactic acid bacteria, and meanwhile, the yield of a cyclic diadenylate precursor ATP is increased by increasing the expression quantity of glycolysis key enzyme PFK; and the ldh gene is knocked out to reduce the accumulation of byproducts, so that the yield of the inner ring diadenylate of the lactic acid bacteria is further improved.

The present invention relates to the technical field of raw materials for toiletries, and specifically discloses a composite extract for preventing hair loss and controlling oil, a preparation method thereof, and an application thereof. The preparation method of the composite extract for preventing hair loss and controlling oil comprises the following steps: step 1), putting the composite plant raw material into a solvent, heating and extracting, and obtaining a pre-extract solution; step 2), cooling the pre-extract solution to ≤36°C, and then inoculating the composite bacteria into the pre-extract solution for fermentation to obtain a fermentation solution; step 3), sterilizing and concentrating to obtain a composite extract for preventing hair loss and controlling oil; the composite plant raw material is a compound of ginseng root, Platycladus orientalis, Polygonum multiflorum, Ligustrum lucidum, Morinda officinalis, Eucommia ulmoides, Milk thistle, and Taxus cuspidatus; the composite bacteria is a compound of Jardine Seberlindner's yeast, Phanerochaete chrysosporium, Hansen's yeast with grape juice, and Lactococcus lactis subspecies creamy. The present invention has the advantage of further improving the anti-hair loss effect.

The invention provides a preparation method of a novel PEDV (porcine epidemic diarrhea virus) subunit vaccine, and belongs to the technical field of biology. The novel PEDV subunit vaccine is prepared by adopting a method comprising the following steps: (1) treating lactococcus lactis by using a high-pressure damp-heat method to obtain peptidoglycan particles; (2) treating the peptidoglycan particles by adopting an ultrahigh-pressure microjet technology to obtain a peptidoglycan carrier with the particle size of 280-850nm; and (3) mixing the peptidoglycan carrier with a PEDV subunit antigen of which the amino acid sequence is SEQ ID NO: 1 to obtain the novel PEDV subunit vaccine. The novel PEDV subunit vaccine comprises a peptidoglycan carrier with a specific size, can improve the in-vivo presentation efficiency of an antigen and rapidly induce efficient body fluid and mucous membrane immune response, and is of great significance to research and development of vaccines for porcine epidemic diarrhea diseases and the like.

The invention belongs to the technical field of biomedical treatment and biological fermentation, discloses a metagen composition for effectively inhibiting oral dental caries and application thereof, and aims to solve the problems of great side effect, weak effect and unknown mechanism of the existing dental caries prevention and treatment means. The composition is prepared by mixing a metagen 1 which is prepared by fermenting lactobacillus salivarius Postbio-YY with a metagen 2 which is prepared by fermenting lactococcus lactis Postbio-F3 and lactobacillus paracasei Postbio-P6 step by step. In the preparation process, the active ingredients are reserved by accurately controlling the fermentation pH, time and pasteurization parameters. The composition can be prepared into multiple dosage forms such as toothpaste and the like, can remarkably inhibit the growth of streptococcus mutans and destroy the thallus structure, inhibits biofilm and exopolysaccharide synthesis by down-regulating fimI, wcaJ and wcae genes, is safe and free of side effects, and provides an efficient scheme for decayed tooth prevention and treatment.

The invention discloses a method for reducing biogenic amine in an air-dried goose product by combining a pulsed electric field with inoculation fermentation, which is characterized by comprising the following steps: treating fresh goose meat at 0.5-1kv / cm for 50-180s, pickling the goose meat in a 8wt% sodium chloride solution for 24h, hanging the pickled goose meat in an air dryer for 1h, draining off water, and drying the goose meat in the air dryer to obtain dried goose meat; the method comprises the following steps: uniformly spraying a compound bacterial solution consisting of lactobacillus plantarum pdd-1 and lactococcus lactis according to the inoculation amount of 1 * 10 < 5 >-1 * 10 < 7 > CFU / mL, and air-drying for 3-5 days at 10-20 DEG C to obtain the air-dried goose product with low biogenic amine, which has the advantages of obviously reducing the content and variety of biogenic amine, inhibiting the degradation of protein in the air-dried goose and obviously increasing flavor substances.

The invention relates to the field of microorganisms, and discloses application of lactococcus lactis in a product for improving sleep. The lactococcus lactis is named as WHH2078, is separated from yoghurt butter collected from a country in Sankarst city in Tibet Autonomous Region in China, is preserved in China General Microbiological Culture Collection Center on February 25, 2021, has a preservation number of CGMCCNO.21831, and is classified and named as Lactococcus lactis. The Lactococcus lactis is named as Lactococcus lactis, and the Lactococcus lactis is named as Lactococcus lactis. The lactococcus lactis has the effects of shortening the sleep latency, prolonging the total sleep time, improving 5-hydroxytryptamine and gamma-aminobutyric acid of the brain, serum and colon, lowering the corticosterone level, regulating back the diversity of intestinal microorganisms alpha, regulating up the abundance of intestinal acidobacilli and lowering the abundance of actinomycetes, desulfurization bacilli and verruca microflora. The sleep disorder can be effectively improved.

The invention discloses lactococcus lactis M6 and application thereof, and belongs to the technical field of microorganisms. The lactococcus lactis M6 provided by the invention is obtained by separating and purifying a kiwi fruit sample picked in Sichuan of China, has multiple functions of high yield of gamma-aminobutyric acid (GABA), high yield of butyric acid, oxidation resistance, antibacterial performance and the like, and has great industrial application value.

The invention relates to the technical field of functional microbial preparations, in particular to a biological preparation for relieving intestinal discomfort caused by alcohol and a preparation method and application thereof.The main technical scheme is that the biological preparation is prepared from, by weight, 5-20 parts of bacillus coagulans, 10-30 parts of pediococcus pentosaceus, 5-10 parts of lactobacillus rhamnosus and 0-20 parts of saccharomycetes. 0-5 parts of bifidobacterium longum and 0-5 parts of lactococcus lactis. By constructing an alcohol metabolism-intestinal protection dual-function synergistic system, specific florae such as bacillus coagulans, pediococcus pentosaceus and lactobacillus rhamnosus are scientifically compatible with functional components such as inulin and L-cysteine, alcohol is efficiently metabolized, and a carbon source is generated; the technical problems of low metabolic efficiency, weak intestinal protection and serious gastric acid inactivation of a traditional product are comprehensively solved.

The invention belongs to the technical field of biological genetic engineering, and discloses a lactococcus lactis carrier oral vaccine for enterotoxigenic escherichia coli F18 fimbriae and application. Four lactococcus lactis antigen surface display strains are prepared and are mixed for oral immunization. The oral immunization mode is convenient to operate, the stress reaction of injection immunization to animals is avoided, meanwhile, the immunization effect is greatly improved, and diarrhea of enterotoxigenic escherichia coli to piglets can be effectively prevented. The escherichia coli vaccine is an oral escherichia coli vaccine, a mouse immune challenge experiment shows that the vaccine can be completely survived under the challenge dosage of LD50, a piglet immune challenge experiment shows that the diarrhea condition of piglets can be completely protected, and it is indicated that an immune group generates effective mucosal immune protection capacity.

The invention relates to the technical field of health-care food, and discloses a health-care composition containing microbial beneficial bacteria and a preparation method of the health-care composition. Comprising the following components in parts by weight: 30-40 parts of gelatinized starch, 8-15 parts of plant enzyme powder, 2-10 parts of microcapsule compound beneficial bacteria, 3-5 parts of selenium-enriched yeast powder, 0.5-2 parts of an American ginseng extract, 12-20 parts of fructo-oligosaccharide, 1-2.5 parts of curcumin, 7-9 parts of ovalbumin and 5-8 parts of sodium carboxymethyl cellulose. Microcapsule composite beneficial bacteria are prepared by compounding bifidobacterium longum, lactobacillus acidophilus, lactobacillus rhamnosus and lactococcus lactis, bridging with carboxymethylated beta-glucan and a Fe < 3 + >-polyphenol network structure and embedding with a protein-polysaccharide system, and can stably exist in an environment with strong acid and high-concentration bile salt to gastrointestinal tracts; through the synergistic effect of different nutrient substances, the intestinal microbe balance can be improved, and the immunity can be remarkably improved.

The invention relates to the technical field of flavor agents, in particular to a butter type bacterium-enzyme co-promoted cheese flavor agent with good sensory characteristics and a preparation method. The flavor agent is composed of hydrolase and active lactic acid bacteria, the hydrolase is prepared from Protease M 'Amano' SD protease, the active lactic acid bacteria are prepared from lactococcus lactis BL-19 (preserved in the China General Microbiological Culture Collection Center, the preservation number is CGMCC 16242), and the fermentation substrate is butter.

The invention relates to selenium-enriched pediococcus acidilactici Se34 with anti-oxidation, cholesterol-lowering and anti-tumor effects and application of the selenium-enriched pediococcus acidilactici Se34. The pediococcus acidilactici Se34 is preserved in the China General Microbiological Culture Collection Center (CGMCC), the preservation number of the pediococcus acidilactici Se34 is CGMCC No.33933, and the preservation date of the pediococcus acidilactici Se34 is March 24, 2025. The pediococcus acidilactici Se34 provided by the invention integrates excellent probiotic characteristics (acid-resistant bile salt, safe and colonizable), efficient selenium enrichment capacity and remarkably enhanced activity of resisting oxidation, reducing cholesterol and inhibiting specific cancer cell proliferation and metastasis after selenium enrichment. The strain and the selenium-rich product thereof have important application value in the fields of developing functional foods (selenium-rich probiotic products), antioxidant / cholesterol-reducing health-care foods, potential auxiliary anticancer biological preparations or prodrugs and the like.

The invention provides lactococcus lactis, a composite dairy leavening agent and application of the lactococcus lactis, the lactococcus lactis has the effects of increasing sweetness and aroma, the classification name of the lactococcus lactis is lactococcus lactis, the preservation number of the lactococcus lactis is CGMCC No.18950, and the preservation date of the lactococcus lactis is November 13, 2019. The strain has the remarkable sweetness increasing and aroma increasing characteristics, and in the fermentation process, the content of the lactococcus lactis in the fermentation process is increased, and the content of the composite dairy leavening agent is increased. Strong FOS (fructo-oligosaccharide) and acetaldehyde generating capacity is shown, endogenous sweet and fragrant flavor substances can be provided for the fermented milk, and the taste and flavor of the fermented milk are remarkably improved. The lactococcus lactis C15, the lactobacillus casei AU9077 and the lactobacillus rhamnosus AU9260 are compounded to obtain the composite dairy leavening agent, the composite dairy leavening agent has a remarkable synergistic effect in the aspect of releasing fructo-oligosaccharide, a stable endogenous sweetening effect is continuously provided for fermented milk, and the requirements of consumers for healthy and flavored dairy products are met while the quality of dairy products is improved.

The invention discloses a streptomyces Targetron gene targeting vector as well as a construction method and application of the streptomyces Targetron gene targeting vector. According to the invention, an II-type intron Ll.LtrB from lactococcus lactis is cloned to an escherichia coli-streptomyces shuttle plasmid to construct a streptomyces genetic manipulation tool-vector pSC30 based on targeting of the II-type intron, and gene targeting in streptomyces coelicolor is successfully realized by using the tool. Screening a biosynthetic gene cluster of red pigment in streptomyces roseosporus; and activating a biosynthetic gene cluster of janus doxorubicin in streptomyces spinosus. According to the invention, the conversion rate and the gene targeting efficiency of the Ll.LtrB intron in streptomyces with high GC content are effectively improved, and a new tool is provided for construction of a gene mutation library.