In order to increase the yield of polysaccharides from Porphyridium cruentum and the cell biomass, we investigated several important cultural conditions such as nutrient-salts, light irradiance as well as growth condi...In order to increase the yield of polysaccharides from Porphyridium cruentum and the cell biomass, we investigated several important cultural conditions such as nutrient-salts, light irradiance as well as growth conditions in the flat plate photobioreacturs （FPPBR） with different light-path. We have found that the optimal （OCM II ） was a superior medium for extracellular polysaccharide production than the f/2 and Koch medium, and the polysaccharide production with OCM II was increased by 1.79 times and 1.62 times compared with that of f/2 and Koch medium; the yields of polysaccharides were also improved by optimizing the light intensity and irradiation length Furthermore, we significantly enhanced the yields of both the biomass and extracellular polysaccharidc using a small light-path photobioreactor, and about 2.1 times increase of polysaccharide production was observed in FPPBR-30 than in FPPBR-100. Overall, the process for polysaccharides production was improved and this would facilitate further studies on such polysaccharidcs such as their antiviral and antitumor activities.展开更多
The key limiting factors to high-density culture of Porphyridium cruentum are the uptake of light energy and nutrient by the microalgal cells. Under the optimal conditions of carrier culture, both cell mass and cell d...The key limiting factors to high-density culture of Porphyridium cruentum are the uptake of light energy and nutrient by the microalgal cells. Under the optimal conditions of carrier culture, both cell mass and cell density were increased significantly up to 5.2 g/L (DW) and 5.2107/ml. Furthermore, the effects of the liquid circulation velocity, light intensity and initial cell density on cell mass productivity of P. cruentum were investigated in a 42 L internal loop airlift photobioreactor. Although the light intensity was as low as 100 mmol/(m2s), the light damage or the photoinhibition phenomenon was observed under the culture condition of low initial cell mass (0.10 g/L, DW) and high liquid circulation velocity (0.30 m/s). However, a higher cell growth rate and a high cell mass productivity were achieved with the same conditions only at high initial cell mass (about 0.80 g/L, DW). Under the optimal conditions, the cell specific growth rate, cell mass volumetric and areal output rate reached to 0.95 d-1, 0.80 g/(Ld) and 42.5 g/(m2d) respectively. Finally, a method of nutrient feeding and gradual increase of light intensity in different cultural stages was developed, which further improved the cell mass, cell mass volumetric and areal output rate to 5.9 g/L, 1.2 g/(Ld) and 61.7 g/(m2d) respectively.展开更多
文摘In order to increase the yield of polysaccharides from Porphyridium cruentum and the cell biomass, we investigated several important cultural conditions such as nutrient-salts, light irradiance as well as growth conditions in the flat plate photobioreacturs （FPPBR） with different light-path. We have found that the optimal （OCM II ） was a superior medium for extracellular polysaccharide production than the f/2 and Koch medium, and the polysaccharide production with OCM II was increased by 1.79 times and 1.62 times compared with that of f/2 and Koch medium; the yields of polysaccharides were also improved by optimizing the light intensity and irradiation length Furthermore, we significantly enhanced the yields of both the biomass and extracellular polysaccharidc using a small light-path photobioreactor, and about 2.1 times increase of polysaccharide production was observed in FPPBR-30 than in FPPBR-100. Overall, the process for polysaccharides production was improved and this would facilitate further studies on such polysaccharidcs such as their antiviral and antitumor activities.
基金Supported by the China Ministry of Science and Technology(No. 96-C02-04-05)
文摘The key limiting factors to high-density culture of Porphyridium cruentum are the uptake of light energy and nutrient by the microalgal cells. Under the optimal conditions of carrier culture, both cell mass and cell density were increased significantly up to 5.2 g/L (DW) and 5.2107/ml. Furthermore, the effects of the liquid circulation velocity, light intensity and initial cell density on cell mass productivity of P. cruentum were investigated in a 42 L internal loop airlift photobioreactor. Although the light intensity was as low as 100 mmol/(m2s), the light damage or the photoinhibition phenomenon was observed under the culture condition of low initial cell mass (0.10 g/L, DW) and high liquid circulation velocity (0.30 m/s). However, a higher cell growth rate and a high cell mass productivity were achieved with the same conditions only at high initial cell mass (about 0.80 g/L, DW). Under the optimal conditions, the cell specific growth rate, cell mass volumetric and areal output rate reached to 0.95 d-1, 0.80 g/(Ld) and 42.5 g/(m2d) respectively. Finally, a method of nutrient feeding and gradual increase of light intensity in different cultural stages was developed, which further improved the cell mass, cell mass volumetric and areal output rate to 5.9 g/L, 1.2 g/(Ld) and 61.7 g/(m2d) respectively.
