A mutant of seawater Arthrospira platensis with high polysaccharides production induced by space environment and its application potential

Abstract

To improve the yields of specific value-added compounds from Arthrospira platensis, one generally accepted method is to obtain mutant strains with increased target component content and growth rate. In the present study, mutation breeding of seawater A. platensis SCSIO-44012 (the wild type strain, hereafter WT) through space-flight carriage by Shijian-10 satellite was carried out. After returning to earth, 183 single filaments were picked out, 43 of which survived. During the following consecutive subcultures, one out of the 43 mutant strains, named A. platensis SCSIO-44012-H11 (hereafter H11), showed stable advantages in high levels of polysaccharides production. The biomass yield, total sugar content, and total sugar productivity of H11 remained stable at 0.88 g L−1, 24.82% DW, and 21.78 mg L−1 d−1, respectively, from the 10th to 35th generations of subculture, which were 8.6%, 62.26%, and 73.68%, respectively, higher than that of WT. The biochemical compositions of polysaccharide extracts (PSE) from H11 and WT also exhibited significant differences. The total sugar content of H11 PSE reached 55.37%, 2.49 times as much as that of WT PSE. The PSE from H11 was enriched in the component cutting off 100 kDa, accounting for 89.32% of the total polysaccharides, whereas WT PSE was mainly composed of the component with a molecular weight between 10 kDa and 50 kDa. The predominant monosaccharide of H11 PSE was glucose, followed by rhamnose, which accounted for 84.53% and 8.13% of the total monosaccharides, respectively. By comparison, glucose and rhamnose occupied 27.33% and 35.41%, respectively, in PSE from WT. Furthermore, the PSE from H11 showed strong ferrous ion-chelating activity and moisture retention capacity. These results indicated the feasibility of H11 as a polysaccharides feedstock applied in cosmetics, nutraceuticals, and medicines.