Research And Development Of Low Cost Liquid Fermentation Technology For Agricultural Polyglutamic Acid

The 19 th Party Congress pointed out that we must build modernization in which people and nature live in harmony,create more material and spiritual wealth,provide more quality ecological products,and create a more beautiful ecological environment to meet the people's growing good life.Bio-fertilizers with micro-organisms as the main component have the effects of improving soil fertility,improving soil environment,and rehabilitating soil structure,and are effective ways to achieve green,harmonious,healthy and sustainable development of agriculture.In this paper,polyglutamic acid produced by Bacillus licheniformis was used as the research object.Firstly,the ability of polyglutamic acid synthesis in the laboratory for the current activation,purification and shake flask fermentation of Bacillus licheniformis and five commercial Bacillus were compared.The strain with the highest potential for growth was selected and subjected to ecological observation and molecular identification.The strain was named Bacillus licheniformis A2-10.We then optimized the A2-10 shake flask level fermentation conditions and determined the best fermentation medium by single factor and orthogonal experiments.The experimental results showed that when the liquid volume was 30mL/300 mL,the medium formulation was 4.37% monosodium glutamate,2% glucose,8% maltodextrin,8% peptone,1.5% potassium sulfate,1.45% sodium chloride,0.15% chlorination Calcium,0.15% magnesium sulfate,inoculum size 5%,pH controlled between 6.5-7.5,polyglutamic acid production reached 30 g/L or more.After the optimization was completed,the fermentation process was optimized and controlled through a 20 L fermenter.The optimization was mainly focused on pH and DO control,and the feeding strategy was optimized.During the experiment,the pH of the fermentation broth was controlled between 6.5-7.5,and the maximum ventilation ratio was controlled to be 0.8 V/Vm.The best feed material was determined to be an aqueous glucose solution,and the reducing sugar concentration of the fermentation broth was maintained at 0.3%.Polyglutamic acid the content reached 35 g/L,and the viscosity of the fermentation broth reached 4800 mPa.s.After the optimization in the 20 L fermenter was completed,a pilot test was conducted on a 500 L fermenter for a total of 5 experiments.The average polyglutamate content was about 34 g/L,and the viscosity of the fermentation broth averaged 4700 mPa.s.The production process of this process is simple and easy to operate,low in cost,low in equipment requirements,and has the conditions for industrial production.Finally,the evaluation and analysis of the application effect of polyglutamic acid preparation in the production of balsam pear greenhouse.The results showed that when the application rate was 500 g/mu,the traits of bitter gourd were significantly improved,and the melon length,melon diameter,fruit shape index,average melon weight,melon shank length,VC content,and soluble sugar content were all significantly improved.It increased by 9.63%,28.64%,16.68%,2.21%,14.79% and 26.72%,respectively,indicating that the inoculant could significantly promote the growth of bitter gourd seedlings and promote bitter melon expansion.