A novel paradigm for the high-efficient production of phycocyanin from Galdieria sulphuraria.

A novel cultivation strategy called "Sequential Heterotrophy-Dilution-Photoinduction" was successfully applied in the cultivation of Galdieria sulphuraria for efficient production of phycocyanin (PC). Algae cells were firstly cultivated heterotrophically to achieve high cell density. The maximal dry cell weight of 17.8gL(-1) and maximal biomass productivity of 103.1mgL(-1)h(-1) were obtained. Then, a dilution step was applied to obtain a suitable cell concentration and finally these cells were transferred to high light condition for phycocyanin accumulation. During the photoinduction step, cells could accumulate phycocyanin up to 13.88% of dry cell weight in a cultivation period of 8days. By this technology, total PC productivity far surpassed those reported in all literatures of Galdieria sulphuraria, and was 147-fold and 12-fold of those in photoautotrophic and heterotrophic technologies, respectively. Therefore, this strategy provides a promising approach for high-efficient phycocyanin production from Galdieria sulphuraria to meet its mass cultivation and commercialization application.

Sequential Heterotrophy-Dilution-Photoinduction Cultivation of Haematococcus pluvialis for efficient production of astaxanthin.

A novel cultivation strategy called "Sequential Heterotrophy-Dilution-Photoinduction" was successfully applied in the cultivation of Haematococcus pluvialis to produce astaxanthin effectively. Cells were first cultivated heterotrophically to achieve a high cell density, then were diluted to a suitable concentration and switched to a favorable environment for cells acclimation. Finally, the culture was transferred to high light environment for astaxanthin accumulation. By this strategy, the dry cell weight of 26 g/L and biomass productivity of 64.1mg/L/h were obtained in heterotrophy stage which surpassed ever before reported in literatures. Meanwhile, the cells could accumulate considerable astaxanthin up to 4.6% of dry cell weight after 10 days of photoinduction. Furthermore, the application prospects of the strategy were confirmed further by outdoor experiments. Therefore, this novel strategy provided a promising approach for high-efficient production of natural astaxanthin from H. pluvialis to meet the huge demand of this high value product.