Studies On The Preparation, Analysis And Bioactivities Of Oligosaccharides From Alginate

The advances and prospects on plant induced resistance, the bioactivities of oligosaccharides to plant, and alginate lysaes were reviewed in this paper. Oligosaccharides from alginate have been reported to act as signal molecular and could induce the resistance reaction, regulate the growth, development, differentiation process in plant, therefore, it was thought to have the potential for practical application in agriculture. The objectives of this paper were to study the preparation, separation, construct analysis of alginate oligosaccharides and put it into field use.Chemical and biological methods were study to prepare oligosaccharides from alginate. Chemical degradation developed in this paper proved to be high yield, less time consuming, no contamination to environment, and meanwhile it need few post treatments to obtain the product. Fermenting combined with ultrafiltration and nanofiltration was carried out to prepare oligomers using alginate lyase producing bacterial. Both the two methods could enlarge to industrial scale.UV and chemical inducer were used to enhance the stability and enzyme activity of bacterial. It showed that UV and chemical inducing together could double the enzyme activity of Alteromonas sp., and meanwhile the concentration of product was enhanced from 15.23 to 71.35.Alginate lyase protein of Alteromonas sp . was cloned and expressed by PLEX expression system. The expressed protein was detected by SDS-PAGE, and the results indicated that a new protein was occurred in the host. But because of the formation of inclusion body, the activity of present expressed protein was very low.5 - 7 fractions of oligo-SA, oligo-HM, oligo-HG were obtained by gel permeation with Bio-Rad P6 column. Unitary peaks were separated from those fractions by semi-preparative HPLC. The DP of those fractions were from 2 to 6, which were conformed by TLC, MALDI-TOF-MS and NMR.The physiological activities of oligo-alginate to some crops were studied in field scale for two years. The results showed that oligosaccharides from alginate could promote the growth of plant, and have the potential to enhanced the output of some crops.