43 results about "Streptomyces aureus" patented technology

The invention relates to a method for producing tetracycline by fermentation of streptomyces aureus. The method comprises the following steps: slant spore culture, seed culture and fermentation culture of the streptomyces aureus, and is characterized in that dextrin, sucrose, corn pulp, hydrolyzed soybean meal and other medium-effect carbon-nitrogen sources are adopted to replace original late-effect carbon-nitrogen sources; by reducing the contents of starch and bean flour in an original fermentation culture medium and combining with a formula of a mixture in the fermentation process and adjustment of a replenishing method and placing part of the nitrogen sources in the fermentation culture medium into material replenishment in the fermentation process, the concentration of the culture medium in the fermentation process is effectively controlled, the oxygen dissolution condition in the early stage of fermentation is improved, the final residue of the culture medium of fermentation is controlled by material replenishment, the material consumption is reduced, and the emission of solid wastes is reduced; the metabolism velocity in exponential growth phase in the fermentation process of the tetracycline is effectively controlled, the abnormal situations that a fermentation solution turns red and becomes sour and the like in the fermentation process are reduced, and the fermentation level is improved.

The invention discloses a preparation method for tetracycline. The preparation method comprises the following specific steps of preparing a streptomyces aureus strain and then performing seed shake-flask culture and seed tank culture; when culture is performed for 20-26 hours, converting the culture mode into fermentation culture; when the pH value reaches 5.6-7.6, the total titer is not smaller than 8,000U / ml, the total saccharides content is not greater than 2.0 percent, the quantity of amino nitrogen is greater than 50mg / 100mL, and the filtering velocity is not smaller than 5mL / 5min, ending the fermentation and discharging from a tank; finally, filtering with a plate frame, decoloring ion exchange resin, crystallizing and performing air current drying to obtain the tetracycline. According to the preparation method disclosed by the invention, a fermentation process is simple, the fermentation unit can be effectively improved, the yield is improved, and the production cost is reduced; meanwhile, the use of chemical organic solvent is avoided.

The invention discloses an organic microbial fertilizer for lettuces and a preparation method thereof. The organic microbial fertilizer for lettuces is prepared from the following components in parts by weight: 4-7 parts of streptomyces aureus, 0.6-0.9 part of bacillus thuringiensis, 3-5 parts of enzyme bacteria, 900-1100 parts of waste liquid precipitates, 240-380 parts of an inorganic fertilizer, 45-55 parts of trace elements, 25-32 parts of an adhesive, 0.5-0.7 part of a stabilizer and 0.1-0.3 part of an effect-stabilizer assistant. The organic microbial fertilizer prepared by the method is capable of increasing the yield of the lettuce, the content of vitamin C and the content of an iron element; and the content of nitrate is reduced, so that the quality of the lettuce is enhanced greatly. Compared with other fertilizers containing the same nutrients, the organic microbial fertilizer is capable of decreasing or lowering crop disease-pest damages which affect the crop quality. The using quantity of a chemical fertilizer is not decreased, and the organic microbial fertilizer is beneficial to environmental protection.

The invention belongs to the field of biopesticides, and mainly discloses a nuisanceless biological compound pesticide and a preparation method thereof. The biological compound pesticide is manufactured from the raw materials of Ailanthus altissima Swingle, Cyrtomium fortunei, geranium wilfordii, fructus forsythiae, Scutellaria baicalensis, gallnut, areca-nut, coconut shell, radix sophorae flavescentis, bacillus subtilis, bacillus licheniformis, Streptomyces rimosus and streptomyces aureus. The Chinese herbal medicine extracts of Ailanthus altissima Swingle, Cyrtomium fortunei and the like are added to the pesticide, so that the antibacterial effect of the biopesticide is greatly improved; and moreover, the Chinese herbal medicine extracts are free of toxic action for people and livestock, so that there is no need to worry about causing harmful effects on people and livestock when the pesticide is used. The biopesticide disclosed by the invention has the characteristics of being high in efficiency, environment-friendly, free of secondary toxicity, residues, pollution or public nuisance and unlikely to generate resistance to drugs and keeping ecological balance, is important guarantee for realizing green ecological agriculture and green enterprises, and has wide prospects.

The invention relates to a seed culture medium and a culture method for streptomyces aureus. The seed culture medium comprises beer yeast dry residue, and particularly comprises the following raw materials: 8 to 10 ml / L oil, 20 to 22 g / L starch, 27 to 29 g / L beer yeast dry residue, 8 to 9 g / L yeast extract, 11 to 13 g / L low temperature soybean cake powder, 0.3 to 0.4 g / L dipotassium phosphate, 0.8 to 1 g / L light calcium carbonate, 0.04 to 0.06 g / L magnesium sulphate, 0.8 to 0.9 g / L sodium chloride, 0.2 to 0.3 g / L amylase, 0.05 to 0.07 g / L ammonium sulfate and 0.03 to 0.04 g / L polyether antifoaming agents. The seed culture medium and the culture method can effectively improve the bacterial cell consistence and bacterial cell culture quality of streptomyces aureus, reduce the inoculum dose in the initial stage of the seed culturing, shorten the seed culturing period, meanwhile reduce the raw auxiliary material dose in the seed culturing to the maximum extent, reduce the production cost, ensure the abundant supply, and realize the stability and high quality culturing of the streptomyces aureus.

The invention relates to the field of fermentation production processes, and discloses a chlortetracycline fermentation production method using refined protein powder. According to the present invention, Streptomyces aureus is adopted as a starting strain, and pure culture and two-stage fermentation are performed to produce chlortetracycline; with the application of the 100% refined protein powder to replace the soybean cake powder, the chemical titer is increased by 2.3% compared to the application of the soybean cake powder, and the yield is increased by 1.8% compared to the unimproved method, such that the yield is effectively increased; and the raw material cost input per tank can be reduced by about 540 yuan after the cost accounting, the effect is good, the fermentation production level is stably increased, and the theoretical and applied basis is provided for the industrial production of the antibiotics and the scientific research.

The invention discloses a method for lowering down the proportion of a by-product produced in fermentation of demethylchlortetracycline. The method comprises the following steps: inoculating the spore of a mutant strain of streptomyces aureus NRRL3203 to a seed medium for culture; and then inoculating a product of seed culture to a fermentation medium for fermentation culture, wherein 150 to 300 ppm of cupric chloride is added into the fermentation medium, and a PH value is controlled in the process of fermentation to allow the PH value to be 6.2 to 6.4 in the period from 0 h to 50 h, 6.0 to 6.2 in the period from 51 h to 100 h and 5.8 to 6.0 in the period from 101 h to time for releasing of fermentation broth from a tank. According to the invention, the spore of the mutant strain of streptomyces aureus NRRL3203 is inoculated into the seed medium for culture and then inoculated into the fermentation medium including cupric chloride for culture, the PH value is regulated and controlled according to the fermentation culture time, so the concentration of the by-product demethyltetracycline in a product is substantially decreased.

The invention relates to a method for increasing the biological value of kasugamycin. A small Streptomyces aureus ordinary culture medium is composed of soybean extraction powder, NaCl, corn steep liquor dry powder, maltose, fish oil, KH2PO4 and inositol, and an optimized culture medium is formed by adding growth factors and trace elements on the basis of the ordinary culture medium. Small Streptomyces aureus is cultured in the culture medium where the growth factors and the trace elements are added, the biological value of kasugamycin is increased by 19.7%, and the yield of single tank is improved by 10.8%. Small Streptomyces aureus cultured by utilizing the culture medium can obviously improve the biological value and the yield of single tank of kasugamycin.

The invention relates to a method for breeding high-yielding strain of tetracycline. The method is characterized by comprising the steps of: adding water into cultured Streptomyces aureus strains to prepare a spore suspension; shaking the flask for cultivation; filtrating; diluting; filling the suspension in four test tubes; adding a same amount of an EDTA solution and acting for respectively 3, 4, 5 and 7min; adding lysozyme and acting for 3 min; conducting gradient dilution to 10<-5>; and coating 0.1, 0.3 and 0.5ml spore liquid from each dilution on plates for cultivation; calculating a forward-mutation rate and a mortality rate; selecting an acting time with high forward-mutation rate; conducting further flask shaking screening; and selecting strains with high increase rate. The invention adopts a method, which first uses lysozyme to remove cell wall and then conducts EDTA treatment, thus breeding high-quality and high-yielding strain of tetracycline; and compared with an ultraviolet method and an ion implantation method, the method provided by the invention has advantages of simple operation, low cost, high safety, little environmental pollution, high mutation rate of strains, and high shake flask titer of the produced strain.

The invention discloses a method for improving aureomycin yield as well as a recombinant expression vector and a genetic engineering bacterium of the aureomycin. The recombinant expression vector is constructed by utilizing an FADH2(Flavin Adenine Dinucleotide) dependent chloride enzyme gene ctcP and an FAD reductase gene ctcQ; the recombinant expression vector is transferred to streptomycesaureofaciens to obtain the genetic engineering bacterium of the high-yield aureomycin; and the bottleneck of chlorination in an aureomycin synthetic route is broken by over-expression of the FADH2 dependent chloride enzyme gene ctcP and the FAD reductase gene ctcQ of the obtained engineering strain, so that the yield of the aureomycin in streptomyces aureus is improved. The strain is obtained for laying a foundation for improving the aureomycin yield and reducing the production cost of the aureomycin.

The invention discloses a preparation method of tetracycline based on fermentation effect improvement. The preparation method includes the following steps that 1, fermentation liquor is prepared: golden streptomyces aureus spores are inoculated to a spore culture medium for culture for 5 days, then the prepared spores are transferred to a seeding tank for culture, and the prepared spores undergo fermentation culture after seed culture is completed; 2, the fermentation liquor is acidified; 3, the separation and purification of the fermentation liquor is are performed: filtration treatment is conducted on the acidified filtrate by using a plate frame, the filtrate obtained after filtration is decolored by using 122 ion exchange resin till the light transmittance of the filtrate is up to 90% or above, the filtrate is fed into a crystallizing tank for crystallization, then centrifugal separation is performed till the water content of wet crystals obtained after separation is up to 20% by mass percentage concentration, the wet crystals obtained through centrifugation are dried, and finally dried powder with the water content of 10% or below by mass percentage concentration is obtained. The preparation method includes few steps, reaction conditions are mild, industrialized production of tetracycline hydrochloride is easy to achieved, and a new thought is provided for production of the tetracycline hydrochloride.

The invention discloses a method for producing aureomycin by using streptomyces aureus. According to the method, a culture medium and a culture method are combined and optimized, so that the synthesis and accumulation of aureomycin are promoted, and the proportion of impurity tetracycline and demethyl aureomycin is further reduced. A high-yield strain breeding model is constructed based on multiple composite mutagenesis and precursor / product tolerance, so that the diversity of a mutation library is higher, the method is simple, convenient and rapid, the screening efficiency is improved, the screening workload is reduced, and the method has certain application value and guiding significance for the reduction of the production cost and the improvement of the productivity of aureomycin andother streptomyces-derived antibiotics. The mutant strain can efficiently synthesize and accumulate aureomycin, the content of the impurity tetracycline and demethyl aureomycin is remarkably reduced, the genetic stability is good, the form, color, aureomycin production level and the content of main impurities are basically stable after continuous passage for five generations, and the mutant strain can be applied to industrial fermentation production and can be used as a production strain for further research and development.

The invention discloses a streptomyces aureus mutant strain, a breeding method thereof and an optimized culture medium. The mutant strain can efficiently synthesize and accumulate aureomycin, the content of impurity tetracycline and demeclocycline is remarkably reduced, the genetic stability is good, the form, color, aureomycin production level and main impurity content of the mutant strain are basically stable after five generations of continuous passage, and the mutant strain can be applied to industrial fermentation production and can be used as a production strain for further research and development. The optimized culture medium is beneficial to promoting synthesis and accumulation of the aureomycin, and the proportion of the impurity tetracycline and demeclocycline is further reduced. A high-yield strain breeding model is constructed based on multiple compound mutagenesis and precursor / product tolerance, the diversity of a mutation library is higher, simpleness, convenience and quickness are achieved, the screening efficiency is improved, the screening workload is reduced, and certain application value and guiding significance for reducing the production cost and improving the productivity of the aureomycin and other streptomycete source antibiotics are achieved.

The invention discloses a microorganism fertilizer for preventing and treating valsa mali of lettuce and a preparation method thereof. The microorganism fertilizer for preventing and treating the valsa mali of lettuce comprises the following components in parts by weight: 4-7 parts of streptomyces aureus, 0.6-0.9 part of bacillus thuringiensis, 3-5 parts of enzyme microorganism, 900-1,100 parts of waste liquid precipitate, 240-380 parts of inorganic fertilizer, 45-55 parts of trace element, 25-32 parts of adhesive, 0.5-0.7 part of stabilizing agent, 0.1-0.3 part of stabilizing effect additive and 24-36 parts of insecticide. According to the method, the waste liquid precipitates produced in an amino acid production process are fully used and are fermented by yeast fungus; the prepared microorganism fertilizer for preventing and treating the valsa mali of the lettuce can greatly reduce the valsa mali morbidity of the lettuce, and the yield of gingers is increased; plants vigorously grow; the quality is also improved; the insecticide component is also added, so that the aphid disease in the growth process is also greatly reduced.

The invention discloses a purification process of tetracycline. The purification process comprises the following steps: 1) preparing a tetracycline crude product: conducting fermentation cultivation of streptomyces aureus spores in a fermentation tank, adding oxalic acid and conducting acidifying treatment; conducting filtration so as to obtain a filtrate, adding calcium salt to the filtrate under an alkaline condition, conducting precipitation, and conducting acid pickling on a precipitate so as to obtain the tetracycline crude product; 2) drying the tetracycline crude product; 3) preparing a tetracycline-inorganic salt dissolved solution, namely, dissolving the dried tetracycline crude product by virtue of a saturated inorganic salt solution, so that the tetracycline-inorganic salt dissolved solution is obtained; and 4) precipitating the tetracycline-inorganic salt dissolved solution, namely, dropping ammonia water to the tetracycline-inorganic salt dissolved solution to regulate pH value to 3-5, decreasing temperature to 0-10 DEG C, keeping the dissolved solution for 1-2h until a tetracycline-inorganic salt precipitate is separated out, and then sequentially conducting vacuum filtration and vacuum drying treatment, so that a finished tetracycline product is obtained. The purification process provided by the invention has fewer steps, so that the loss of the tetracycline in a purifying process is reduced.

The invention discloses application of streptomyces aureus Tu117 as a marker for detecting and diagnosing hypertension to preparation of a corresponding detection tool. A detection object of the detection tool is excrement, intestinal tissues or intestinal contents collected from a subject. The streptomyces aureus Tu117 of the invention is relatively high in content in bodies of hypertension model mice and hypertension patients, can be used for establishing a detection method or preparing a detection and diagnosis kit, and is used for auxiliary diagnosis and risk assessment of hypertension and prehypertension.

The invention relates to a bevel solid culture medium and culture method for producing tetracycline through fermentation of streptomyces aureus. The culture medium is prepared from, by weight, 2.0-2.5% of bran, 0.005-0.008% of dipotassium phosphate, 0.008-0.013% of diammonium hydrogen phosphate, 0.003-0.006% of magnesium sulfate, 0.5-1.0% of corn steep liquor, 0.003% of calcium carbonate, 1.8-2.5%of agar and the balance water. By changing the raw material composition in the streptomyces aureus bevel solid culture medium, the defect that culture quality fluctuation is caused by raw material quality fluctuation in the original formula is overcome, it is ensured that the prepared bevel spores are stable in both appearance and culture activity, and the fermentation level is also stably improved.

The present invention relates to a method for increasing the fermentation level of tetracycline. The method is characterized in that during a fermentation process of tetracycline production using Streptomyces aureus as a fermentation strain, the carbon source and the nitrogen source of a material supplementation culture medium and other substances are subjected to separated sterilization, and the separated material supplementation is performed according to the requirements of the strain on the carbon source and the nitrogen source. According to the present invention, the carbon source and the nitrogen source in the material supplementation culture medium during the fermentation production process using the Streptomyces aureus as the fermentation strain are respectively subjected to the sterilization treatment, the quality of the material obtained through the method is good, the adverse effect of the toxic substance produced from the sugar and nitrogen mixed sterilization on the bacteria is reduced, the utilization efficiency of the sugar water is increased, and the fermentation level is increased; and during the material supplementation process, the material supplementation amount is flexibly controlled according to the requirements of the strain on the carbon source and the nitrogen source, such that the requirements of the bacterial growth reproduction and synthesis at the growth stage can be completely met, the high degree utilization of the carbon source and the nitrogen source can be ensured, the supplementation amount during the process can be reduced, the fermentation unit can be increased, and the material consumption can be reduced.

The invention provides a bio-organic fertilizer and a preparation method thereof. The bio-organic fertilizer is mainly prepared from streptomyces aureus and humus, wherein the humus is mainly formed by humic acid, straw and soybean cake through fermentation; in the bio-organic fertilizer, the content of the streptomyces aureus is greater than or equal to 20 million / g. The streptomyces aureus and the humus in the organic fertilizer have the effects of functional complementation and synergistic interaction; the growth of harmful microbes can be inhibited; the disease resistance of plants is promoted; poor environment is resisted; meanwhile, the vigorous growth of various plants is promoted; the yield and the quality of crops are obviously improved. The preparation method has the advantages that the streptomyces aureus and the humus are mixed according to a weight ratio to obtain the bio-organic fertilizer; the method is simple; the implementation is easy; the operation is convenient; the mass production of the bio-organic fertilizer is facilitated.

The invention discloses a keratin producing bacterial strain as well as culture conditions and crude enzyme property thereof and belongs to the technical field of microorganisms. Through identification, the bacterial strain is Streptomyces aureofaciens, named as K13 and preserved in CGMCC (China General Microbiological Culture Collection Center) with the preservation number of CGMCC NO.8047. Through preliminary optimization, the culture medium of the bacterial strain comprises 0.5-1% of wool, 4-8% of glucose, 3-5% of peptone, 0.3% of sodium nitrate, 0.04% of dipotassium phosphate and 0.05% of sodium chloride; the shake culture conditions are that the initial pH (potential of Hydrogen) value is 10.0, the inoculation quantity is 10%, the culture temperature is 30 DEG C, the rotating speed is 220 revolutions per minute, the liquid loading volume is 30ml / 250ml, the fermentation period is 64 hours and the keratinase producing activity is up to 44.2U / ml. The keratinase is mesophilic alkaline keratinase, the optimum operation temperature is 50-60 DEG C and the optimum pH is 8.5; the enzyme activity of the keratinase is stable in an alkaline environment (pH 7.0-10.0).

The invention relates to a seed culture medium and a culture method of Streptomyces aureus. The seed culture medium contains brewer's yeast dry residue, which is composed of 8-10ml / L of oil, 20-22g / L of starch, and 27-29g / L of brewer's yeast dry residue. L. Yeast extract 8-9g / L, low-temperature soybean cake powder 11-13g / L, dipotassium hydrogen phosphate 0.3-0.4g / L, light calcium carbonate 0.8-1g / L, magnesium sulfate 0.04-0.06g / L, Sodium chloride 0.8-0.9g / L, amylase 0.2-0.3g / L, ammonium sulfate 0.05-0.07g / L and polyether defoamer 0.03-0.04g / L. The present invention can effectively improve the concentration of Streptomyces aureus cells and the quality of cell culture, reduce the inoculum amount at the initial stage of seed culture, shorten the seed culture period, and at the same time reduce the amount of raw and auxiliary materials in seed culture to the greatest extent, reduce production costs, and ensure sufficient supply. Achieve stable and high-quality cultivation of Streptomyces aureus.

The invention discloses a streptomyces aureus mutant strain, a breeding method thereof and an optimized culture medium. The mutant strain can efficiently synthesize and accumulate aureomycin, the content of impurity tetracycline and demeclocycline is remarkably reduced, the genetic stability is good, the form, color, aureomycin production level and main impurity content of the mutant strain are basically stable after five generations of continuous passage, and the mutant strain can be applied to industrial fermentation production and can be used as a production strain for further research and development. The optimized culture medium is beneficial to promoting synthesis and accumulation of the aureomycin, and the proportion of the impurity tetracycline and demeclocycline is further reduced. A high-yield strain breeding model is constructed based on multiple compound mutagenesis and precursor / product tolerance, the diversity of a mutation library is higher, simpleness, convenience and quickness are achieved, the screening efficiency is improved, the screening workload is reduced, and certain application value and guiding significance for reducing the production cost and improving the productivity of the aureomycin and other streptomycete source antibiotics are achieved.

The invention discloses a synthesis method of tetracycline HCl convenient for seed tank cleaning. The synthesis method comprises the following steps: 1) preparing a fermentation broth: inoculating a spore medium with streptomyces aureus spores and conducting cultivation for 5 days, then transferring the prepared spores to a seed tank and cultivating the spores, and after conducting cultivation in the seed tank, conducting fermentation cultivation; 2) acidifying the fermentation broth; 3) preparing tetracycline coarse alkali: adding calcium chloride to the fermentation broth and conducting precipitation so as to obtain a calcium salt precipitate, and regulating the pH value of the calcium salt precipitate to 4.6-4.8; 4) preparing a finished tetracycline alkali product; 5) preparing the tetracycline hydrochloride: adding the finished tetracycline alkali product to a butanol solution, adding hydrochloric acid and conducting filtration, and conducting heating crystallization so as to obtain the tetracycline hydrochloride; and 6) preparing the tetracycline HCl: processing the tetracycline hydrochloride by virtue of carbonate so as to obtain the tetracycline HCl. The synthesis process provided by the invention has fewer steps and is mild in reaction conditions, and the synthesis process can easily implement the industrial production of the tetracycline HCl; therefore, a new thinking is provided for the production of the tetracycline HCl.

The invention relates to a construction method of tetracycline anoxia-tolerance strains. The construction method comprises the following steps: constructing a plasmid pSET152 capable of expressing a vitreoscilla hemoglobin gene; transforming the constructed plasmid pSET152 into escherichia coli PUZ8002; and carrying out conjugational transfer on the transformed escherichia coli PUZ8002 and streptomyces aureus, so that the tetracycline anoxia-tolerance strain is obtained. The tetracycline anoxia-tolerance strain constructed by using the method disclosed by the invention can improve the protein expression level of recombinant tetracycline under low oxygen conditions, thereby finally achieving the purpose of energy saving and cost reducing.

The invention discloses a preparation method for tetracycline. The preparation method comprises the following specific steps of preparing a streptomyces aureus strain and then performing seed shake-flask culture and seed tank culture; when culture is performed for 20-26 hours, converting the culture mode into fermentation culture; when the pH value reaches 5.6-7.6, the total titer is not smaller than 8,000U / ml, the total saccharides content is not greater than 2.0 percent, the quantity of amino nitrogen is greater than 50mg / 100mL, and the filtering velocity is not smaller than 5mL / 5min, ending the fermentation and discharging from a tank; finally, filtering with a plate frame, decoloring ion exchange resin, crystallizing and performing air current drying to obtain the tetracycline. According to the preparation method disclosed by the invention, a fermentation process is simple, the fermentation unit can be effectively improved, the yield is improved, and the production cost is reduced; meanwhile, the use of chemical organic solvent is avoided.

The invention discloses a strain of Streptomyces albus Z9 for preventing and treating sclerotinia in sunflower seedling stage. The preservation number of the strain is CGMCC 13115, which belongs to the technical field of microorganisms. Through the implementation of experiments such as the isolation, activation and identification of the pathogenic sclerotinia of sunflower sclerotinia, the primary screening and re-screening experiments of antagonistic bacteria, and the identification and analysis of antagonistic bacteria, it was shown that the strain Z9 has a strong ability to inhibit the hyphae of Sclerotinia sclerotiorum ability to grow. The infection rate of sunflower seed husks treated by the strain Z9 fermented original bacterial liquid of the present invention is reduced by 70%, the germination promotion rate of the bacterial strain Z9 fermentation filtrate is 33.3%, and the control effect of the isolated leaves of the bacterial strain Z9 fermented original bacterial liquid 69.6%, and the pot experiment control effect of bacterial strain Z9 fermented original bacterium solution is 66.7%, which can effectively inhibit the growth and reproduction of Sclerotinia sclerotiorum. The bacterial strain of the invention has simple culture conditions, is easy to preserve, is environmentally friendly, and has good development and application value.

The invention belongs to the technical field of aureomycin fermentation, and particularly discloses an aureomycin seed production method capable of adjusting pH of a culture medium by using ammonia water. Streptomyces aureus is used as an original strain, and aureomycin is obtained by pure culture and three-stage fermentation. The aureomycin seed production method comprises the specific process steps of: a sandy soil spore preparation procedure, a mother bottle inclined plane spore preparation procedure, a child bottle inclined plane spore preparation procedure, a first-stage seed preparation procedure, a second-stage seed preparation procedure and a fermentation preparation procedure. In the first-stage seed preparation procedure, the pH value of an inactivated seed culture medium is adjusted by the ammonia water, and the pH is adjusted by the ammonia water after the culture medium is disinfected, and by controlling the dropping speed of the ammonia water and adding the ammonia water at a proper time, in one aspect, the pH can be buffered, and in the other aspect, a quick-acting nitrogen source can be provided for spore growth, thereby achieving high quality and low price.

The invention relates to a method for producing tetracycline by fermentation of streptomyces aureus. The method comprises the following steps: slant spore culture, seed culture and fermentation culture of the streptomyces aureus, and is characterized in that dextrin, sucrose, corn pulp, hydrolyzed soybean meal and other medium-effect carbon-nitrogen sources are adopted to replace original late-effect carbon-nitrogen sources; by reducing the contents of starch and bean flour in an original fermentation culture medium and combining with a formula of a mixture in the fermentation process and adjustment of a replenishing method and placing part of the nitrogen sources in the fermentation culture medium into material replenishment in the fermentation process, the concentration of the culture medium in the fermentation process is effectively controlled, the oxygen dissolution condition in the early stage of fermentation is improved, the final residue of the culture medium of fermentation is controlled by material replenishment, the material consumption is reduced, and the emission of solid wastes is reduced; the metabolism velocity in exponential growth phase in the fermentation process of the tetracycline is effectively controlled, the abnormal situations that a fermentation solution turns red and becomes sour and the like in the fermentation process are reduced, and the fermentation level is improved.

The invention discloses an organic microbial fertilizer for lettuces and a preparation method thereof. The organic microbial fertilizer for lettuces is prepared from the following components in parts by weight: 4-7 parts of streptomyces aureus, 0.6-0.9 part of bacillus thuringiensis, 3-5 parts of enzyme bacteria, 900-1100 parts of waste liquid precipitates, 240-380 parts of an inorganic fertilizer, 45-55 parts of trace elements, 25-32 parts of an adhesive, 0.5-0.7 part of a stabilizer and 0.1-0.3 part of an effect-stabilizer assistant. The organic microbial fertilizer prepared by the method is capable of increasing the yield of the lettuce, the content of vitamin C and the content of an iron element; and the content of nitrate is reduced, so that the quality of the lettuce is enhanced greatly. Compared with other fertilizers containing the same nutrients, the organic microbial fertilizer is capable of decreasing or lowering crop disease-pest damages which affect the crop quality. The using quantity of a chemical fertilizer is not decreased, and the organic microbial fertilizer is beneficial to environmental protection.