The present study developed a two-step strategy to enhance the production of extracellular polymeric substances (EPSs) by a thermotolerant chlorophyte, Graesiella sp., in view to their industrial valorisation. In the first step, Graesiella sp. was grown in outdoor conditions in pilot-scale photobioreactors of 100 L culture volumes. In the second step, the biomass collected in the exponential growth phase was submitted to heat stress (50 °C). A joint production of biomass reaching 0.50 g_dw L⁻¹ day⁻¹ and of EPS production reaching 1.30 g_dw L⁻¹ in 2 days was obtained. EPSs mainly contained polysaccharides (80%) and proteins (14%). FTIR and ¹HNMR revealed the presence of primary amine and sulfated groups. The EPSs contained antioxidant enzymes (SOD, CAT, and APX) maintained in an active state by the microenvironment offered by the EPSs. The EPSs were found to have a potent antioxidant activity via directly scavenging free radicals when compared to l-ascorbic acid.

鉴于其工业价值，本研究开发了一种分两步的策略来增强耐热绿叶植物Graesiella sp。的胞外聚合物质（EPS）的产生。第一步，Graesiella sp。在室外条件下在100 L培养体积的中试规模光生物反应器中生长。在第二步中，将在指数生长期收集的生物质置于热应力（50°C）下。获得了在两天内联合生产生物量达到0.50 g _dw  L ^-1 天^-1和EPS产量达到1.30 g _dw  L ^-1的联合生产。EPS主要包含多糖（80％）和蛋白质（14％）。FTIR和¹HNMR显示存在伯胺和硫酸化基团。EPS包含的抗氧化酶（SOD，CAT和APX）通过EPS提供的微环境保持活跃状态​​。与1-抗坏血酸相比，发现EPS通过直接清除自由基具有有效的抗氧化活性。