Optimization of exopolysaccharide production by Rhizobium radiobacterPTCC 1654 in the sludge dairy usingresponse surface methodology

In this study, exopolysaccharide production by Rhizubium radiobacter PTCC 1654 in Submergedfermentation to reduce waste sludge from dairy Industries as well as used as Beneficialmedium for the growth kind of microorganisms, were studied. Initial screening was used fractional factorial designs with 7 variables of time, temperature, concentration of calcium carbonate, ammonium sulfate concentration, Agitation rate, the percentage of dairy sludge and pH medium for the identification of variables affecting the growth of R. radiobacter Was performed. The results showed that three variables of dairy sludge, calcium carbonate concentration and time of incubation had positive effect on the growth of R.radiobacter(p<0/05). Moreover, that all variables, have a significant effect on the production of exopolysaccharideExopolysaccharides by R. radiobacter using response surface methodology(p<0/05).The maximum production of EPS was in concentration 1g/l calcium carbonate, 50% of dairy sludge and incubation time 101/69 hours, in which case exopolysaccharide production 0/686 g/100 ml and biomass production0/288 g/100 ml is. FTIR results showed that the exopolysaccharides produced in the dairy sludge has residues of carbohydrate, and carboxyl groups on its chain.