Study On Liquid-Solid Fermentation Technics Of High Density Preparation Of Streptomyces S506

Therefore the vegetation micro-ecological is environmentally friendly,wide effect,low cost,it is widely concerned by the world,and has become an interest research area. Streptomyees sp.S506 is one of PGPR strains isolated from tomato rhizosphere.It could effectively control root diseases of many vegetables,and could also significantly promote root development and degrade autotoxicity of the root.The strain had wide application prospect in effectively controlling continous croppiny obstacle.How to improve density and titer of the biogen has been the key factor to put it into application.In the study,S506 was used as test material.The optimum liquid-solid two-phase fermentation parameters were studied in flask.The scale-up test was studied in koji tray, and the solid product was obtained.The koji tray amplification test has been done,and through the pot experiment,application effect test have been carried out using the obtained solid product.Seed activity,the alive cells amount and the lag phase of solid fermentation were used as test index.Liquid seed fermentation culture medium and technological conditions of Biogen-S506 were studied by single factor experiments and orthogonal experiments.The results showed that the optimum parameters were obtained as follows:bran powder 3%, corn meal powder 3%,soybean cake powder1.5%,KNO₃ 0.6%,K₂HPO₄ 0.3%,glycerol 1.0%,NaCl 0.4%,CaCO₃ 0.3%,FeSO₄ 0.05%,MgSO₄ 0.05%,natural pH,liquid volume in flask 100mL/500mL,fermentation temperature 35℃,rotation speed 150rpm, fermentation time 84h.Under this condition,the alive cells amount of Biogen-S506 will reach to 6.75×10⁹cfu/mL.Alive cells amount and conidium amount were used as test index.Based on comprehensive consideration of fermentation characteristics,production costs and material source,the optimum solid fermentation culture medium were obtained as follows:bran 100 g,KNO₃ 0.1 g,mineral matter M 15 g,K₂HPO₄ 0.3 g,NaCl 0.25 g,CaCO₃ 0.8g;the optimum technologic parameter were:natural pH,the initial moisture content 60%, inoculum volume 10%,liquid seed age 84h,fermentation temperature 30℃,fermentation time 60h.Under the optimized conditions,the alive cells amount of Biogen-S506 will reach to 8.27×10⁹cfu/g,and the number of conidium is 7.20×10⁹cfu/g.The promoting plant growth titer of Biogen-S506 produced at those process parameters was significantly higher than the type of carrieres absorbing.A test was made on the fermentation parameter of solid fermentation in koji tray.The optimum parameters were obtained as follows:material thickness 8cm,turning koji at 30h, fermentation time 72h.Under these conditions,the alive cells amount of Biogen-S506 will reach to 8.47×10.9cfu/g,and the number of conidium is 7.27×10⁹cfu/g.The number of alive cells can still reach to 6.89×10⁹cfu/g,and the survival rate can reach 81.35%after solid biogen preserved eight months later at room temperature.The results showed that the products had good preservation characteristics.In the application of the obtained product in protected tomato and cucumber,it could increase the dry weight of root crops by 30%and enhance root length over 20%,whose control effect on the root pathogens was more than 80%.