Switching Cultivation For Enhancing Biomass And Lipid Production With Exteracellular Polymics Substances As Co-products In Heynigia Riparia SX01

The low productivity in traditional autotrophic cultivation seriously hinder the development of microalgae industry.At the same time,due to the lack of high value co-products in this process,the total profit appears to be further decline.The purpose of this experiment is to solve the above problem and realize the commercial production of biodiesel.Different culture conditions on microalgae was researched for high-density culture and extracellular polymeric substance?EPS?was developed as high value co-productsIt has been suggested that the lipid production of microalgae could be significantly affected by the culture conditions.In the present study,the switching cultivation,mixotrophic-heterotrophic?12:12 h?,was proposed.The maximum biomass concentration of 3.55 g/Land lipid yield of 1.45 g/L for Heynigia riparia SX01 were achieved after 8 days cultivation.The EPS was developed as co-products.The highest amount of 0.60 g/LEPS was obtained with addition of 2 g/LMgSO₄,the self-flocculation efficiency was as high as 85%.The total lipid and lipid fractions did not show differences with extra MgSO₄.Based on the above results,further experiments was done to analyze the structure and function of EPS,and evaluate its potential as flocculant.In the end,a new biodiesel production model was proposed:culturing Heynigia riparia SX01 with extra 2 g/LMgSO₄ by switching cultivation and using self-flocculation to collect microalgae for biodiesel production,while supernatant was collected to obtain EPS as valuable co-products.The present study developed a strategy for high biomass and high quality lipid production with higher yield of EPS as co-products in Heynigia riparia SX01,which was of great significance for the commercial development of microalgae biodiesel.