Study On Biotransformation By Debaryomyces Hansenii Fermentation Through Wastewater From Monosodium Glutamate

Monosodium glutamate wastewater(MGW)which is a wastewater in the process of production of monosodium glutamate contain a rich source of ammonia nitrogen,Direct emission to the river not only caused environment pollution but also waste of resources.To solve the problem mentioned above this study used Debaryomyces hansenii screened by Academy of state Administration of Grain.which make use of MSG into growth.The culturing condition and the medium using MSG were optimized and pilot expansion experiment was performed.At last as feed additives add into fodder.In this study,firstly we optimized process parameter of Debaryomyces hansenii by single factor experiment as pre-experiment.According to the result,8 independent variables were evaluated by using PB design.Temperature,glucose addition,Zinc chloride addition were indefinite as significantly affecting biomass.Then the center points of 3 factors were determined base on steepest ascent design optimization of these significant factors was carried out by using Box-Behnken design.The optimal culture conditions were as follows: initial PH4.5,inculum size 2 %,temperature 30℃,fermentation time 5days,culture volume 40/300 mL.The medium conditions were as follows: 2.3 % glucose addition,0.4 % zinc chloride water: corn steepwater : MGW=1:4:1.Under these condition the biomass of yeast were 5.82 %。To optimize the cell autolysis processing of Debaryomyces hansenii cultured in monosodium glutamate waste water,the response surface methodology was used in this study.The cell lysis rate was considered as response value of the response surface methodology,which was based on single factors of time,temperature pH and cosolvent.Time at 23 h,temperature at 54℃,pH at 5.5,addition of papain of 0.8 % were found to be the optimal conditions to autolysis of D.hansenii.Under the condition,the content of amino acid nitrogen in the yeast cell lysis solution was 14.76 g/L,which was close to the predicted optimal value 14.84 g/L.The model was reliable and the strategy for optimization of yeast cell autolysis was feasible,which could be applicable for guiding production practices.Based on the optimized conditions,the fermentation processes for yeast cultivate and autolysis were scaled up for 100 L pilot enlarge production for animal feeding experiment.Using pure culture as control group.The optimum technique in spray drying were as follow: inlet flowing rate 100mL/min,inlet temperature 200℃.The PDA pure culture group contain 15.6 % crud protein,14.63 % protein,2.68 % nitrogen amino acid,2.04 %crude polysaccharide.The group contain MGS found to contain 33.8 % crude protein,30.02 %protein,3.69 % nitrogen amino acid,7.39 % crude polysaccharide.11.8 % sulfuric acid.adding 4 g/kg group contain MGS can improve broiler growth.MGW-wastewater and yeast resource be full used,through microbial fermentation wastewater be utilized as feed additives.It has promising economic value and social benefits.