The effects of several nutritional factors on the growth and eicosapentaenoic acid （EPA） production of diatom Nitzschia laevis were studied. 4LDM （quadrupled concentration of the nutrient salt） was the optimal con...The effects of several nutritional factors on the growth and eicosapentaenoic acid （EPA） production of diatom Nitzschia laevis were studied. 4LDM （quadrupled concentration of the nutrient salt） was the optimal concentration of nutrient salt for the growth and EPA production ofN. laevis. The growth ofN. laevis was inhibited when the glucose concentration was either lower than 10gL^-1 or higher than 15 gL^-1. Both sodium nitrate and urea were good nitrogen sources for the growth and EPA production, while ammonium chloride seriously decreased the dry cell weight （DW） and the EPA content. Silicate seriously influenced the growth of N. laevis. The maximum DW of 2.34 gL^-1 was obtained in the presence of 150 mgL^-1 Na2SiO3· 9H2O. The EPA content remained almost the same when the silicate concentration was lower than 150mgL^-1; however, higher silicate concentrations resulted in a steady decrease of EPA content. Low medium salinity （≤29） did not seem to influence the DW of N. laevis, and high salinity resulted in a decrease of DW. The highest EPA content （4.08%） and yield （110mgL^-1） were observed at the salinity of 36 and 29, respectively. Key words polyunsaturated fatty acid; eicosapentaenoic acid; microalga; Nitzschia laevis; heterotrophy展开更多
One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate...One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate was chosen as the organic nutrient to test the combined effects of organic and inorganic solutions on the growth and fatty acid composition of Brachiomonas submarina. The best growth rates were achieved at 3 mmol L -1 CH 3COONa and 0.88 mmol L -1 NaNO 3 in heterotrophic condition, and 4 mmol L -1 CH 3COONa and 3.52 mmol L -1 NaNO 3 in mixotrophic condition. The differences between fatty acid contents were significant. The total polyunsaturated fatty acids (T.P.U.F.As) varied from 55.79% to 67.72% in heteritrophic growth and from 52.39% to 65.55% in mixotrophic growth. It is concluded that CH 3COONa and NaNO 3 at 3 mmol L -1 and 3.52 mmol L -1 should respectively be used in order to achieve the highest growth rate and fatty acid content.展开更多
文摘The effects of several nutritional factors on the growth and eicosapentaenoic acid （EPA） production of diatom Nitzschia laevis were studied. 4LDM （quadrupled concentration of the nutrient salt） was the optimal concentration of nutrient salt for the growth and EPA production ofN. laevis. The growth ofN. laevis was inhibited when the glucose concentration was either lower than 10gL^-1 or higher than 15 gL^-1. Both sodium nitrate and urea were good nitrogen sources for the growth and EPA production, while ammonium chloride seriously decreased the dry cell weight （DW） and the EPA content. Silicate seriously influenced the growth of N. laevis. The maximum DW of 2.34 gL^-1 was obtained in the presence of 150 mgL^-1 Na2SiO3· 9H2O. The EPA content remained almost the same when the silicate concentration was lower than 150mgL^-1; however, higher silicate concentrations resulted in a steady decrease of EPA content. Low medium salinity （≤29） did not seem to influence the DW of N. laevis, and high salinity resulted in a decrease of DW. The highest EPA content （4.08%） and yield （110mgL^-1） were observed at the salinity of 36 and 29, respectively. Key words polyunsaturated fatty acid; eicosapentaenoic acid; microalga; Nitzschia laevis; heterotrophy
文摘One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate was chosen as the organic nutrient to test the combined effects of organic and inorganic solutions on the growth and fatty acid composition of Brachiomonas submarina. The best growth rates were achieved at 3 mmol L -1 CH 3COONa and 0.88 mmol L -1 NaNO 3 in heterotrophic condition, and 4 mmol L -1 CH 3COONa and 3.52 mmol L -1 NaNO 3 in mixotrophic condition. The differences between fatty acid contents were significant. The total polyunsaturated fatty acids (T.P.U.F.As) varied from 55.79% to 67.72% in heteritrophic growth and from 52.39% to 65.55% in mixotrophic growth. It is concluded that CH 3COONa and NaNO 3 at 3 mmol L -1 and 3.52 mmol L -1 should respectively be used in order to achieve the highest growth rate and fatty acid content.
