Preparation of oligosaccharides from alginate by fermenting combined with membrane separation method and analysis of the oligomers
微生物发酵-膜分离法制备褐藻胶寡糖及其产物分析

Changes in biomass, oligosaccharides content and alginate lyase activity in broth of Alteromonas sp. incubated in shaking flask and fermentation jar were studied. According to those changes, parameters were established for preparing oligosaccharides from alginate by fermentation combined with nano-filtration membrane separation method. Resulting oligosaccharides were analyzed by gel permeation chromatography and thin layer chromatography. One liter culture medium(pH 7.5) contains 5 g yeast extract, l0 g peptone, 0.1 g FeSO4, 12 g sodium alginate and 1.5 g NaCl. When incubating at 28 degrees C, the result showed that the optimal fermentation time was 30 h to obtain the highest production of oligosaccharides in the broth. After ultra-filtration and nano-filtration, 94.0% of the total oligosaccharides was recovered from the broth, and meanwhile 93.3% of the salt was removed. Gel permeation chromatography and TLC analyses indicated that the resulting oligosaccharides were composed of five fractions with different degree of polymerization.