Preliminary Study On Growth Conditions And Lipid Accumulation Of Cylindrotheca Sp

The six benthic diatoms strains of Cylindrotheca sp.(B156, B164, B169, B192, B200,B209) that were obtained from the Microalgae Culture Center (MACC), Ocean University ofChina were cultured under25±1℃, the light intensity was2500xl, the salinity was30±1, themedia was f/2. Under above conditions, different strains of Cylindrotheca sp. the cell density,chlorophyll fluorescence characteristics, chlorophyll content, total lipid content and fatty acidcomposition were different. According to the above parameters and practical needs selected twostrains from the six strains of Cylindrotheca sp.. Use the two strains of Cylindrotheca sp. asexperimental material, cultured the algae under different growth conditions (media, salinity,nitrogen concentration, phosphorus concentration, silicon concentration). At a particular time ofevery day count the cell density and determine the Chlorophyll fluorescence parameters(F_v/F_m,F_v/F_o, ΦPSII, rETR and qP); At the end of the experiment, determine the chlorophyll content,the total lipid content and the fatty acid composition of Cylindrotheca sp.. Based on the aboveparameters selected the appropriate culture conditions, and provide the basis for thedevelopment of Cylindrotheca sp.The results showed that:The cell density of B169and B192were reached the highest values in8f treatment, thelowest values were reached in f/4treatment. In8f media, from day3to day9, the F_v/F_mand F_v/F_owere significantly higher than those in other treatments. The media in f/4to8f, the chlorophyllcontent of B169reach the highest values in2f, but there was no significant difference with4f,the chlorophyll content of B192were reached the highest values in4f treatment. The highesttotal lipid content of B169and B192, respectively appear in f and f/4treatment. Under differentmedia the C20:4n-6(Arachidonic acid) and C20:5n-3(EPA) of B169and B192all in high lever.The B169and B192in salinity20to cell density increase most at the end of culture. Fromday1to day9, the F_v/F_mand F_v/F_owere reached the highest values in salinity50and70. TheB169in salinity5the ΦPSII and rETR were significantly higher than those in other treatments.The chlorophyll content of B169and B192were reached the highest values in salinity20; and the highest total lipid were in salinity10. The C20:5n-3and the total content of polyunsaturatedfatty acids of B169were reached the highest values in salinity50, The C20:4n-6content wasreached the highest values in salinity5but there was no significant difference with salinity50.The C20:4n-6content of B192was reached the highest values in salinity30and the highestC20:4n-6content was12.97%of total fatty acid but there was no significant difference withsalinity50, and that algae’s C20:5n-3was reached the highest values in salinity90and thehighest C20:5n-3content was15.06%of total fatty acid.The cell density of B169and B192increased most in N3treatment at the end on theexperiment. From day1to day9, the N6treatment of B169, the F_v/F_mand F_v/F_oSteady at thehigher level. The F_v/F_mand F_v/F_oof B192in N2and N6were higher. The highest chlorophyllcontent were in N6. The highest total lipid content and chlorophyll content of B169was in N4but the total lipid content was no significant difference with N5. The nitrogen concentrationswas no significant affected the total lipid content of B192. The C20:4n-6and C20:5n-3wererespectively reached the highest values in N4and N6. The C20:4n-6and the total content ofpolyunsaturated fatty acids of B192increases with the nitrogen concentrations, and theC20:4n-6and C20:5n-3were respectively reached the highest values in N6and N5.The cell density of B169and B192were increased most in P6treatment at the end on theexperiment，and in Phosphorus deficiency treatment (P1) the cell density were increased Least.In P5treatment the ΦPSII and rETR were significantly higher than those in other treatments.The chlorophyll content of B192and B169were reached the highest values in P5. The highesttotal lipid content of B169was in P5and of B192was in P3. The C20:4n-6and C20:5n-3ofB169were respectively reached the highest values in P7and P4treatment, the highest contentwere11.92%and8.26%of total fatty acids. The C20:4n-6, C20:5n-3and the total content ofpolyunsaturated fatty acids of B192were increases with the phosphorus concentrations and thendecreases, the highest content were17.14%,14.52%and43.25%of total fatty acids.The cell density of B169was higher in high silicon concentrations than in low siliconconcentrations. In day4to day9, the cell density of B192in Si4treatment was significantlyhigher than those in other treatments, and in Si6treatment cell density was lowest. From day1today9, the F_v/F_mand F_v/F_oof Si6treatment was significantly higher than those in othertreatments, and from day1to day7, the ΦPSII and rETR of Si5and Si6were significantly lower than those in other treatments. The chlorophyll content of B169reach the lowest values in Si1treatment; the chlorophyll content of B192reach the lowest values in Si6treatment.The totallipid of B169and B192were reached the highest values in Si1treatment, and those werereached the lowest values in Si6treatment. The C16:3n-4, C20:4n-6, C20:5n-3and the totalcontent of polyunsaturated fatty acids of B169and B192were increases with the siliconconcentrations, and in Si4and Si5treatment were reached the highest values.According to the above parameters to examine the feasibility of the biochemical methodsand chlorophyll fluorescence techniques in development of Cylindrotheca sp., and explore thevary growth conditions those effect the total lipid accumulated of Cylindrotheca sp., so thatprovide the basis for the development of bio-diesel and further large-scale cultured.