Optimization Of Fermentation Process And Evaluation Of Fertilizer Efficiency For Producing Amino Acid Water-soluble Fertilizer By Mixing Rapeseed Meal And Soybean Meal

Amino acid water-soluble fertilizer is a kind of water-soluble fertilizer with amino acid as the main part.It can add medium and trace elements according to the proportion required by plants.It can also be mixed with chemical fertilizer.It is a new type of fertilizer with great development prospect.Rapeseed meal and soybean meal are byproducts of edible oil processing and extraction,which are rich in carbon,nitrogen and trace elements.Water soluble fertilizer with high amino acid content can be produced by microbial fermentation,which has important theoretical and practical significance for the resource utilization of agricultural waste and the development of ecological high-value agriculture.In this paper,the mixture of rapeseed meal and soybean meal was used as raw material.Lactobacillus plantarum G71 preserved in the laboratory,Commercial Saccharomyces cerevisiae and Bacillus subtilis were used to degrade the vegetable meal by fermentation.The amino acid solution was obtained after extraction and centrifugation.The components of amino acid solution were detected,and then the appropriate amount of amino acid solution was applied to pot experiment.In the end,the fertilizer effect was evaluated.The main research results of the paper are as follows.1)The mixed fermentation conditions of rapeseed meal and soybean meal were optimized.Rapeseed meal: soybean meal was mixed into raw materials according to the ratio of 7:3,and protease was added.Taking the content of free amino acid as the evaluation index,the mixed ratio of Saccharomyces cerevisiae,Bacillus subtilis and Lactobacillus plantarum was determined as 1:1:1 by orthogonal experiment design;Single factor experiment was used to explore the best feed-water ratio is 1:7,the best starting p H is 9,the best turning interval is 24 h,the best inoculum is 3%,and the best fermentation time is 216h;through PB experiment,the most significant influence on the amino acid content in the fermentation process is obtained.The order of significance from high to low is: fermentation time> material-to-water ratio> initial p H;Through the climbing experiment,the level of each significant factor is closer to the optimal level,which increases the effectiveness of the BBD experiment;Through the BBD Experiments have determined the optimal fermentation conditions for mixed bacteria fermentation,and a fitted quadratic regression equation is obtained.The relationship between the strain and various factors in the equation is significant.It indicates that the fit and credibility of the equation are all very high;The best fermentation combination optimized by the experiment is: fermentation time 217.7h,initial p H 9.1,material-towater ratio 1:7,inoculation amount 3%,and turning interval 24 h.It has been verified that the yield of free amino acids reached 7.68(g/100g).The measured value is relatively close to the theoretical value,and the free amino acid output reaches the maximum.2)The effect of amino acid water-soluble fertilizer was evaluated.Taking tea seedlings as experimental plants.Pot experiment was conducted.Five treatments were set up,including self-made amino acid water-soluble fertilizer(2ml,10 ml and 50ml),commercially available water-soluble fertilizer and clean water.Tea seedlings were irrigated with fermented amino acid water-soluble fertilizer every 15 days.After three months of pot experiment,growth index,photosynthesis index and quality index of tea seedlings were measured.The results showed that amino acid water-soluble fertilizer had a good application effect on tea seedlings when the application amount was 10 ml.The growth index test results showed that the leaf number,plant height and stem diameter of tea seedlings increased by 25.0%,32.0% and 30.5% respectively;the photosynthesis index test results showed that the SPAD value of tea seedlings increased by 32.1%,and the net photosynthetic rate,stomatal conductance and transpiration rate increased by 0.712(μ mol /(M2 · s)),0081(mol /(M2 · s))and 0.231(mmol /(M2 · s))respectively;The content of amino acids,tea polyphenols and caffeine increased by25.89%,22.36% and 18.15%,respectively.The results showed that there were significant differences between 10 ml self-made amino acid water-soluble fertilizer treatment group and water treatment group,and there were certain significant differences between other treatment groups.In conclusion,the fermentation optimization of rapeseed meal and soybean meal mixture by mixed bacteria can effectively improve the amino acid content of fermentation broth and the utilization rate of resources.It has great significance for the development of ecological high-value agriculture.The evaluation of amino acid watersoluble fertilizer shows that amino acid water-soluble fertilizer has significant fertilizer effect and long-term development potential.It has extensive guiding significance for tea seedling and other crops.