Study On Culture Conditions And Active Compounds Of Nostoc Punctiforme

Nostoc is an edible alga, it produce many kinds of natural active compounds.These compounds can be developed into many areas such as medicine, foods, aquaculture, agriculture, environment protection and so on. Some commercial compounds, for example pigments, antibiotics, antivirus, anti-eumycetes, cytotoxin, polysaccharides, vitamins and sterin, were found from Nostoc, and it also is a source of valuable drugs.In this thesis, BP nerual network was used to optimize the culture conditions for biomass and extracellular polysaccharide by Nostoc punctiforme. The biomass and extracellular polysaccharide were 14.3% and 66.2% higher than the control respectively. For antioxidant activity assay on exopolysaccharides, both of crude extracellular polysaccharide and deproteinization-polysaccharide of Nostoc punctiforme were effectly scavenging superoxide radical system, hydroxyl radical, oxidation system of linoleic acid. By determination the inhibition ability of alcohol extract and extracellular polysaccharide of Nostoc punctiforme on five common pathogenic bacterias, the result showed that they could effectly inhibit Staphylococcus aureus, Bacillus coli and Bacillus subtilis. Five kinds of protein fractions were isolated and purified from Nostoc punctiforme, and then detectived the inhibitory activity against cancer ceils HL60 and K562. We found that five protein fractions had inhibitory effect on HL60 and K562, and among them NP2 fraction was the best.