硒在紫球藻蛋白质、多糖和脂类物质中的累积与分布

Accumulation and distribution of selenium in protein,polysaccharide and lipid of Porphyridium sp.

目的探讨硒对紫球藻的生长及其主要生化组成的影响,分析紫球藻累积同化硒的动态过程及其硒在细胞主要生化组成中的分布特点。方法利用添加0.5 mg.L-1硒的ASW培养基培养紫球藻(Porphyridium sp.),采用2,3-二氨基萘(DAN)荧光分光光度法测定藻体及各主要生化组成中的硒含量。结果与结论 (1)0.5 mg.L-1硒能够促进紫球藻的生长,最大干重可达到4.8 g.L-1,比对照组增加0.6 g.L-1,添加硒后紫球藻胞外分泌性多糖的产量明显提高,加硒组胞外分泌性多糖含量为180.7 mg.L-1,是对照组的1.69倍。添加硒培养紫球藻不会影响其生化组成和品质。(2)藻体硒含量在对数前期增加明显,由11.19μg.g-1增加到17.78μg.g-1;在培养中后期硒含量出现迅速升高,达到26.95μg.g-1,净增量为9.17μg.g-1;富硒紫球藻细胞的最高硒含量达到27.99μg.g-1,是对照组硒含量的14倍。每单位体积(L)培养物中,紫球藻富集硒的总量为140.16μg,硒的同化率达到28.03%。(3)添加硒后紫球藻培养物中胞外分泌性多糖的硒含量为31.02μg.g-1,,比藻体硒含量高3.03μg.g-1。藻体内硒主要分布在胞体多糖中,硒含量为7.08μg.g-1(DW),是细胞硒含量的25.3%,水溶性蛋白质和粗脂肪结合硒的量分别为5.84μg.g-1(DW)和0.89μg.g-1(DW),分别占细胞硒含量的20.9%和3.2%。

Objective The effect of selenium on the algal growth and the major biochemical components,the dynamic process of selenium accumulation and its distribution characteristic in the major biochemical components were investigated.Methods Porphyridium sp.was cultured in ASW medium containing 0.5 mg·L-1selenium.Selenium contents of the algae and the major biochemical components were determined by 2,3-DAN fluorimetry.Results and Conclusion（1） Se（0.5 mg·L-1） could promote the algal growth.The maximum cell dry weight（4.8 g·L-1） was 0.6 g·L-1 more than that of the control,and the yield of extra-polysaccharide reached 180.7 mg·L-1,which was 1.69 times higher than that of the control.The major biochemical components and algal growth status were not impacted by selenium addition.（2） The intracelluar selenium content increased apparently from 11.19 μg·g-1to 17.78 μg·g-1during the early logarithmic phase.Then the content continued to rise rapidly up to 26.95 μg·g-1and the net increment was 9.17 μg·g-1 during the mid-late stage of culture.The maximum intracelluar selenium content（27.99 μg·g-1）was 14 times higher than that of the control.The total amount of selenium accumulated by Porphyridium sp.reached 140.16 μg per liter culture and the rate of assimilation was 28.03%.（3） The selenium content of exopolysaccharide was 31.02 μg·g-1,which was 3.03 μg·g-1 more than that of the algal cell biomass.The intracelluar selenium was mainly distributed in polysaccharide which has the selenium content of 7.08 μg·g-1（DW）and accounted for 25.3%of that total celluar selenium content.The selenium contents of water-soluble protein and crude lipids were 5.84 μg·g-1（DW） and 0.89 μg·g-1（DW）which accounted for 20.9% and 3.2%,respectively.