| There are some advantages of Isochrysis galbana parke, such as the small size, not cell wall, easy to be digested, high contain of oil. So it has been used extensively as food, health products, cosmetics, pharmaceutical and feed. As a kind of little algae with important economic worth, more and more attention was paid to research of I.galbana.Culture conditions of the I.galbana were optimized in a kind of novel flat-panel photobioreactor in this work. The maximal cell densities, growth rates and productivities of the I. galbana in the flat-panel photobioreactor were comparied under different temperatures, different light intensities and different light paths. The contents of polysaccharide, protein and total lipid in algae cells under different culture conditions were determined.The growth rate of I. galbana was significantly different under different light paths(P<0.05). The volumetric productivity of the biomass increased with the decrease of the light path. But daily areal productivity of the algae cells increased with the increase of the light path. The growth rate of the cell increased with the increase of the light intensity under the temperture of 20℃and 24℃. Under the culture temperature of 28℃, the growth rate of the cells increased firstly and then decreased with the increase of light intensity. Exposed under the same light intensity, the growth rate of the algae cells rised firstly and then reduces with the rise of temperature. The growth rate of the cells was the highest under temperature of 24℃, and it was significantly higher than it was under 20℃and 28℃(P<0.05).The content of nutrients in the algal cells was different in the different light paths photobioreactors. The contents of total lipid in the cells cultured in the 5cm, 8cm and 10cm light path photobioreactors was 27.95%, 25.56% and 23.58%, respectively. The content of the total lipid was slightly higher than it was reported in the past. The contents of the polysaccharide were 11.64mg/g, 10.6mg/g and 9.86mg/g, respectively. The content of the proteins was 23mg/g, 22.3mg/g and 21.9mg/g, respectively. The content of nutrients in the algal cells was also different under different culture temperatures and light intensities. When the culture temperature was 20℃, with the increase of the light intensity, the content of polysaccharide increased(P<0.01). But when the culture temperature was 24℃and 28℃, the content of polysaccharide increased firstly and then reduced (P<0.05) with the increasing of the light intensity. Low temperature was favorable to the accumulation of polysaccharide in the cells under same light intensity. The variation of the protein contents in the cells was basically identical to the change of the growth rate. Content of the proteins was the highest in cells under 24℃and 6400lux. Within the specific limits, the content of the lipid increased with increase of the light intensity, but it decreased with the increase of the temperature (P<0.05).The content of polysaccharide and proteins was the lowest during the lag phase, and was the highest during the steady phase. The dry weight of single cell reached the highest at the late lag phase. It was 0.511×10-9g.cell-1. It did not obviously change during the logarithmic phase and steady phase.The content of DHA and EPA in the algal cells cultured under the conditions of 20℃, 6400lux were determined. The results showed that the content of DHA and EPA was 20.49% and 11.26%, respectively.The experiments offered some theoretical results and facts verification to the culture and the application of the I. galbana. The results offered some certain value for the use of the I. galbana in the different fields.
|
PDF Full Text Request