Synthesis, Optimization and Modeling of Curdlan Gum Production from Paenibacillus polymyxaUsing Response Surface Methodology (RSM)

Curdlan gum is a bacterial polysaccharidic biopolymer that is the result of β-(1→3)-D-glycosidic linkages. Due to its ability to curdle and the water-holding capacity, curdlan has applications in the manufacture of food products such as jelly, noodles, edible fibers. Curdlan is biodegradable, nontoxic and it has applications in the pharmaceutical industry because of its potent biological activities. For the first time, the present study is concerned with the synthesis, characterization, optimization of cultural conditions and modeling of curdlan production from Paenibacillus polymyxa using RSM. After preparation of the microorganism and the medium, Plackett–Burman design with 12 experimental runs was used to screen the effective factors through 11 variables of batch culture medium for curdlan production. Central composite design with 20 experimental runs was used for optimization of the effective variables. In addition, four characterization methods such as FT-IR, C-NMR, XRD and DSC were employed. The result of the experiments showed that three nutritional factors (glucose, yeast extract and triton x-100) had the predominant effect on curdlan production. The maximum production of curdlan was 4.75 g/l from the optimum condition consisting of glucose (100 g/l), yeast extract (3 g/l) and triton x-100(2.5 g/l). In addition, the average molecular weight of curdlan was determined at 170 kDa by GPC. The results from this study have demonstrated that Paenibacillus polymyxa PTCC 1020 with more specific growth rate (µ) than previous studies is capable to produce curdlan gum and also the production of the synthetic curdlan was confirmed using qualitative methods of identification.