Optimization of bifidobacterium pseudocatenulatum KAKii cultivation conditions for exopolysaccharide production using response surface methodology / Aliza Mahdi

Bifidobacteria is gram-positive, non-motile, non-spore-forming and strictly anaerobic bacteria. It is belongs to phylum Actinobacteria and able to produce exopolysaccharide (EPS). EPS extracted from the Bifidobacteria are polymers of sugars, long chained polysaccharide that have been shown to give benefit towards human health. This study were conducted with the aim to optimize the EPS production by Bifidobacterium,considering the benefits of EPS to the human health. Initially, study was conducted to select Bifidobacterium strains with highest EPS production, then optimize the growth conditions, which were pH (range of 5, 6 and 7), incubation temperature (20 oC, 30 oC and 40 oC) and cultivation time (6, 21 and 36 hours), and lastly to characterize the EPS produced by using FT-IR and GC-MS. During the selection of Bifidobacteria strains, results found that Bifidobaterium pseudocatenulatum KAKii showed highest EPS production compared to the other two strains (B. pseudocatenulatum KAKii and B. animalis). While the optimization of the three factors towards B. pseudocatenulatum KAKii found that EPS produced crucially depends cultivation time (23.59 hours) rather than pH (5) and temperature (34.75 oC). The validation showed that the predicted (115.89 mg/100mL) and experimental values are not significantly different (p > 0.05), indicating that the developed model is fitted well for the optimization. FT-IR spectrum also showed peak that could be attributed to common stretching of hydroxyl group (3435.58 cm-1), symmetric C-H stretching (2088.70 cm-1), stretching of C=O and carboxyl group (1645.74 cm-1) including C-O stretching peak (712.59 cm-1). The FT-IR spectrum supported common pattern of FTIR spectra of EPS extracted from other probiotic indicated that the EPS extraction was successful. GCMS chromatogram on the other hand support previous studies on B. pseudocatenulatum to produce acetic acid during EPS production. The result also showed that EPS extracted from the strain was composed of D-glucose, mannose, galactose and maltose thus indicated that EPS was from hetero-exopolysaccharide group.