Study On The Fermentation And Metabolites Of Streptomyce Griseorubens JSD-1

Degradation of straw by using microbial can effectively solve the problems of resources waste and environmental pollution. But researches on the study of microbial, owning the ability to degrade straw, mainly focused on the bacteria and fungi at present, and researches on the study of the actinomycetes and its application pay less attention. Besides, the production capacities of enzyme activity and the rate of degradation still need to be improved. By taking Streptomyces griseorubens JSD-1 as the research’s object, response surface methodology was used for optimizing the growth medium, enzyme production medium and fermentation conditions, respectively. Also the GC/TOF-MS was used to study and analyze the metabolites of straw biodegradation by JSD-1. Resultes as follows:Millet culture medium was screened for the best growth medium of JSD-1 and optimize its composition and concentration. Plackett-Burman experimental design was using to screen significant impact factors for further analyzing by Box-Benhnken response surface design. The optimized medium contained: millet 13.35 g/L, calcium carbonate 6.26 g/L, peptone 4 g/L, glycerol 20 g/L, sodium chloride 3 g/L, under the optimum conditions, the maximum biomass of JSD-1 reached 10.36 g/L, 59% higher than before.Effects of different kinds of carbon source inducer and surfactants on the production of cellulase from JSD-1 were investigated. Results show that the activity of cellulase has been significant increased when 2% concertration of bran was added. filter paper activity(FPA), exoglucanase(CBHase)and total protein were also higher when Tween 20 was added. That is because Tween 20 can promote the cell growth effectively by increasing the membrane permeability of the S.griseorubens JSD-1 and the secretion of extracellular enzymes, changing the fermented liquid surface tension and improving the oxygen transfer rate of the fermentation system. The added concentration of Tween 20, culture temperature and pH were optimized by using response surface analysis(RSA), and 1.47%, 32℃, and 7.51 were determined, respectively. Under the optimum conditions, the cellulase activity reaches the highest value of 65.482 U/mL.The parameters of the fermentation process of S.griseorubens JSD-1 was investigated by Using the 5 L fermentation tank.And pH value was determined to have a great effect on the activities of cellulase production, therefore, a two-stage control strategy of pH is proposed which is controlling the pH value of 8.0 at the only 48 hours of fermentation to maintain a higher output of biomass.And then control the pH of 7.5 till the end of the fermentation to provide a better environment to promote the CMCase and FPase of S.griseorubens JSD-1. Effectiveness of the strategy was proved by rice straw degradation test.Metabolism of the growth of S.griseorubens JSD-1 and extracellular metabolites of the degradation were measured by using GC/TOF-MS. Results show that the straw degradation products by JSD-1 are mainly organic acids. And the ability of transforming amino acid in the fermentation process is the strongest. The intermediate metabolite, forming in the process of amino acid metabolism transforming the TCA cycle, are involved in the TCA cycle of the strains.