Studies On Solid State Fermentation Of Antagonistic Microbia 34-9 And γ-60-11 To Control Postharvest Diseases In Citrus Fruit

Postharvest diseases of citrus cause major losses,which are primarily controlled by synthetic fungicides.A new,high efficacy and innocuity microbial biocontrol agent are needed to be producted instead of fungicide because people have concerned about environmental contamination and human health risks associated with fungicide residues and because the widespread use of these fungicides has led to the proliferation of resistant strains of the pathogens.At the present time,antagonist is produced with liquid in-depth fermentation technics,the equipment and the technology are complicated while the costs highly. The solid state fermentation uses raw material which is generally the inexpensive agricultural subsidiary products.And the equipment is comparatively simple.The fermentation product is obtained after the simple treatment,the production cost is lower than the liquid fermentation greatly.The solid fermentation media to cultivate the strain 34-9 and the mutantγ-60-11 was screened,and investigated the solid fermentation technology conditions.The scientific basis are provided by the research of the solid fermentation medium and conditions for the development of effective antagonist product.Main conclusions were drawn as follows.1.The characteristic of biologicol yeast is studied,the optimum concentration and time of cultivation are confirmed:The prime components of Kloeckera apiculata 34-9 are analyzed,the growth curves of isolate 34-9 andγ-60-11 in liquid were made,optimum time of cultivation of the strain 34-9 is 14h and the mutafacient strainγ-60-11 is 16h with concentration of 5×10⁸ cells mL^-1.2.The prime solid fermentation media formula were screened:On shaking flask solid fermentation level,the optimum culture medium of 34-9 in solid fermentation was screened,bran:meal:bean cake=1:4:1,glucose 30g/kg,(NH₄)₂SO₄ 9g/kg, KH₂PO₄9g/kg,peptone 5g/kg,MgSO₄·7H₂O₂.4g/kg,ZnSO₄·7H₂O0.4g/kg, MnSO₄·7H₂O0.02g/kg,CaCl₂·2H₂O0.12g/kg,biotin0.1 mg/kg, Calcium-D-pantothenate 30mg/kg,lactoflavin 6mg/kg.The optimum culture medium of mutafacientγ-60-11 in solid fermentation was screened,bran:meal:bean cake=1:3:2,glucose 30g/kg,(NH₄)₂SO₄ 9g/kg, NaH₂PO₄ 9g/kg,peptone 10g/kg,MgSO₄·7H₂O 2.4g/kg,ZnSO₄·7H₂O 0.4g/kg, MnSO₄·7H₂O 0.02g/kg,CaCl₂·2H₂O 0.12g/kg,biotin 0.1mg/kg,inositol 3mg/kg, Thiamine hydrochloride 6 mg/kg,lactoflavin 0.6mg/L.3.The prime solid fermentation conditions were obtained:Carry out experiments separately on different temperature,fermentation time,quantity of inoculation and the proportion between solid media and water,to find out the best results of them.The optimum conditions of 34-9 were fermentation temperature 30℃,quantity of inoculation 15%,the proportion between solid media and water 1:1,the fermentation time 32 hour.The optimum conditions of the mutafacient strainγ-60-11 were fermentation temperature 28℃,quantity of inoculation 15%,the proportion between solid media and water 1:1,the fermentation time 28 hour.We found that the quantity of inoculation was higher the product quantity was higher.4.The prime conditions of the fermentator were optimized:On fermentator level, whisk speed is 8r/min,clockwise 60s followed with 3s space,and then reverses 60s; at the first 12h,the ventilation quantity is 1m³/h,the 1.5m³/h between 12h and 36h, finally 12h is 1m³/h.