Optimization And Kinetics Analyses Of Exopolysaccharide Production By Simplicillum Lanosoniveum

Simplicillium lanosoniveum var tianjinienss Q.L.Dong?DT06?which is a Deuteromycetes fungus is capble of producing unique exopolysaccharide?EPS?.The EPS secreted by fungus DT06 has a potential application value in the aspect of food and medicine.In this paper,fungus DT06 was as experimental material.Based on single factor experiments,the optimum culture conditions for EPS yield coefficient were determined applying Box–Behnken design?BBD?.Under the optimized conditions,fermentation kinetic parameters and metrology was analyzed through a mass of data.At first,screening fungus DT06's medium with the highest EPS yield coefficient,As the results showed,sabourand medium is the optimum medium for producing EPS.Secondary,cultivate composition?glucose,peptone?and culture conditions?pH,temperature,rotation?were set five constant-gradient,respectively.As is shown in single factor experiments,three significant factors?glucose,peptone,pH?and two non-significant factors?temperature and rotation?,which were determined.Based on single factor experiment,a three-level,three-factor BBD response surface methodology?RSM?was applied to optimize the EPS synthesis conditions.RSM analysis suggested good correspondence between experimental and predicted value.Under the optimized conditions(40.65 g/L glucose,10.38 g/L peptone,pH 4.87,temperature 30?and rotation speed 140 r.min^-1),the highest EPS yield coefficient 0.139 g/g was obtained,which increased 32%compared to that before optimization.Kinetic analysis indicate that the maximum specific growth rate(?_max)of DT06 is0.156 h^-1,while its EPS synthesis is semi-growth-associated with a maximum specific production rate 0.066 h^-1.The experimental verification demonstrated that kinetic models established successfully simulated fungus DT06 fermentation process.By comparing the data,fungus DT06 is relative higher than those of othere EPS-producing Fungi.Nevertheless its average EPS yield coefficient is relative low.Carbon-balance analysis revealed that apart from EPS DT06 also produced a unknown neutral products with a carbon yield coefficient of 0.129 g/g.These results provide essential parameters for controlling DT06's fermentation process and improving its metabolic network.