微波法提取球等鞭金藻胞外多糖的工艺

Microwave extraction process of extracellular polysaccharide in Isochrysis galbana

采用微波法,通过一系列单因素试验,研究了时间、微波功率、温度和pH对球等鞭金藻胞外多糖提取的影响。在此基础上,利用正交试验进一步优化胞外多糖的微波提取工艺。最后,比较微波提取法和热水浸提法制备的球等鞭金藻胞外多糖样品的红外光谱,并测定样品中蛋白质和多糖含量。单因素结果表明,微波功率、温度和pH均能显著影响球等鞭金藻胞外多糖的提取。正交试验结果表明,微波法提取球等鞭金藻胞外多糖的适宜微波功率、温度和pH依次为500W、75℃和6。微波提取法和热水浸提法制备的多糖产率分别为64.7mg/g和41.7mg/g。其中,前者蛋白质和多糖含量分别为0.48%和32.7%,后者中蛋白质和多糖含量依次为1.86%和22.1%。综上所述,在球等鞭金藻多糖提取过程中,微波法明显优于热水浸提法。红外光谱测定表明,胞外多糖和胞内多糖在结构上存在某些相似性,即均含有酰氨基,且都含有以半乳糖为构架的分子模式;二者在结构上还存在明显差异,即前者不含硫酸基,也不存在β-吡喃环结构。

Effects of time, microwave power, temperature and pH on the extraction of extracellular polysaccharide in Isochrysis galbana through a series of single factor test using microwave method were studied. And optimized further extraction process of polysaccharide by orthogonal experiments. Finally, the extracellular polysaccharides collected by the microwave extraction and hot-water immersed method, and determined of protein and polysaccharide contents and compared of IR spectra of those samples. The results showed that the microwave power, temperature and pH could significantly affect the extracellular polysaccharide extraction. Orthogonal experimental results showed that extracellular polysaccharide of the appropriate extraction process as follows： microwave power, temperature and pH were 500 W, 75 ℃ and 6. The extracellular polysaccharides collected by two extraction methods have similar IR spectra. Under the best condition of 500 W, 75 % and pH6, the recovery ratio is 64.7 mg/g （extracellular polysaccharide/dried weight） which is higher than that by hot water extraction, 41.7 mg/g （extracellular polysaccharide/dried weight）. And the protein and polysaccharide content of the extracellular polysaccharide samples were 0.48% and 32.7% by microwave extraction, and protein and polysaccharide content of the extracellular polysaccharide samples were 1.18% and 22.1% by hot water immersed method, respectively. IR spectra showed that extracellular polysaccharide and intracellular polysaccharide have some similarities in structure. That is, all containing amido and galactose as framework of molecular model. However, the two kinds of polysaccharide still exist obvious differences in structure. That is, the former contained not sulfuric acid medium and there was no beta-pyran ring.