The Study Of Fermentation Conditions Of Pseudoalteromonas Paragorgicola RS-2 And Vibrio SplendidusRS-8 And Application In Sea Cucumber Culture

in this paper the fermentation conditions,optimized medium of the strains including Pseudoalteromonas paragorgicola RS-2 and Vibrio splendidusRS-8 were studied .the effect of application in sea cucumber culture were evaluated.The fermentation conditions of Pseudoalteromonas paragorgicola RS-2 were investigated through single-factor and Response surface methodology.the optimized fermentation conditions and medium were:temperature 25℃, initial pH 7.5,and shaking at 250 r/m,the most suitable medium was identified as following: trypton 0.6698g/100ml,yeast extract 0.3296g/100ml , NaCl₂4.38g/L ,Fe₂(PO₄ )30.01g/L,MgSO₄.7H₂O 6.92g/L MgCl₂.6H₂O 5.51g/L CaCl₂.H₂O 1.45g/L KCl 0.67g/L,distilled water 100mL.the viable number of Pseudoalteromonas paragorgicola RS-2 in the optimized medium could raised to 1.067×10⁹cfu/mlThe single-factor test and response surface analysis were used to determine the optimized fermentation conditions and medium of Vibrio splendidusRS-8. the experimental results showed that the most suitable fermentation conditios and medium were: temperature 25℃, initial pH 6.0,and 150r/min shaking at r/m,the most suitable medium was identified as following: trypton 0.5 g/100ml, yeast extract 0.2829g/100ml,NaCl19.92g/L,Fe₂(PO₄ )30.01g/L, MgCl₂.6H₂O 13.20g/L CaCl₂.H₂O 1.45g/L KCl 0.67g/L,,distilled water 100mL.the viable number of Vibrio splendidusRS-8 in the optimized medium could raised to 2.10×10⁸cfu/ml,In application experiment, Pseudoalteromonas paragorgicola RS-2 and Vibrio splendidusRS-8 were added into marine culturing water for sea cucumber juveniles with final concentration at 10⁴cfu/ml and 10⁶cfu/ml, respectively. DGGE technology was applied to analyze the microflora dynamics of sea cucumber culturing water. The results showed that the survival rate of sea cucumber juveniles was significantly higher in two bacteria-treated group compared to control. Microflora were obviously more stable in two probiotic-treated group than those in the controls, the result show that adding Pseudoalteromonas paragorgicola RS-2 or Vibrio splendidusRS-8 at 10⁴cfu/m and 106cfu/ml was able to enhance the microflora of marine culturing water and improve the health of sea cucumber juveniles.