Abstract

PEREIRA DUTA, Flávia; PESSOA DE FRANCA, Francisca  and  DE ALMEIDA LOPES, Léa Maria. Optimization of culture conditions for exopolysaccharides production in Rhizobium sp. using the response surface method . Electron. J. Biotechnol. [online]. 2006, vol.9, n.4, pp. 0-0. ISSN 0717-3458.

The combined effects of the processing parameters for exopolysaccharides production by Rhizobium sp. was studied using the experimental design and response surface methodology. The experiments were carried out using a fermenter with 20 L capacity, as the reactor. All processing parameters were online monitored. The temperature [(30 ± 1)ºC] and pH value (7.0 ± 0.1) were kept constant throughout the experimental time. As statistical tools, a complete 2³ factorial planning with central point and response surface were used to study the interactions among three relevant variables of the fermentation process: calcium carbonate concentration, aeration and agitation. The processing parameters setup for reaching a maximum response for exopolysaccharides production was obtained when applying the highest values for calcium carbonate concentration (1.1 g/L), aeration (1.3 vvm) and agitation (800 rpm). In addition, the combination of these optimum processing parameters yielded Y_P/S (g/g) = 0.35.

Keywords : exopolysaccharides; experimental design; response surface method; Rhizobium sp..