The Growth,lipids And Arachidonic Acid Accumulation Of Parietochloris Incisa In Different Photobioreactors

The Chlorophyta Parietochloris incisa comb.nov?Trebouxiphyceae?was found to be the richest plant source of the pharmaceutically valuable long-chain polyunsaturated fatty acids?PUFAs?,arachidonic acid?AA?.This paper mainly studied the effect of light intensity,nitrogen source and concentration,the change of the mediun under different nitrogen species,the length of the different light-path of column and flat plate photobioreactors on the growth,total lipid and AA content of P.incisa.Cell growth of P.incisa and Thermosynechococcus elongatus was also studied on the new photobioreactor.The main experimental results as follows:1.Different responds of two kinds of light intensities,three kinds of nitrogen sources and five concentrations on the growth,total lipids and AA of P.incisa on the column photobioreator?6.0 cm?.The largest biomass,obtained in 300 ?mol·m^-2·s^-1intensity,8.8 m M Na NO3 condition,was 4.17 g·L-1.The biggest total lipids were41.17%?Na NO3?,42.04%?NH4HCO3?and 39.96%?CO?NH2?2?under 100?mol·m^-2·s^-1 intensity and 1.0 m M nitrogen concentration condition.AA content reached the highest?16.44%DW?in 300 ?mol·m^-2·s^-1 intensity with 2.9 m M Na NO3.The highest of total lipid and AA volumetric production rate,in the 300?mol·m^-2·s^-1 intensity and,for maximum under the condition of nitrogen source for Na NO3,respectively 134.6 mg·L-1·d^-1?1.0 m M?and 35.85 mg·L-1·d^-1?5.9 m M?.2.The medium,which replacement of three kinds of nitrogen speices after seven day of cultivation,had the significant effects for the growh,total lipid content and AA accumulation of P.incisa on the column photobioreactor?6.0 cm?.Among them,the highest biomass was 4.97 g·L-1 in the 8.8 m M NH4HCO3 turned into 8.8 m M NH4HCO3 conditions.The biggest total lipid content?42.13%?obtained in the 17.6m M Na NO3 turned into 0 m M Na NO3 condition.The maximum total lipid volumetric production rate(120.17mg·L-1·d^-1)obtained in the 17.6 m M Na NO3 changed to 17.6m M Na NO3 condition,while 8.8 m M NH4HCO3 turned to 0 m M NH4HCO3 had the largest AA content?9.13% DW?and production rate(24.70 mg·L-1·d^-1).3.Under 300 ?mol·m^-2·s^-1 light intensity,using two different Na NO3 nitrogen concentrations in three kinds of light-path of column photobioreactor had significantly influence on the growth,total lipid and arachidonic acid accumulation of P.incisa,which,in the 2.5 cm light-path,had the largest biomass under 17.6 m M Na NO3?5.09g·L-1?.Largest total lipid and AA content obtained in 6.0 cm light-path,1.0 m M Na NO3 cultivation condition,39.23% and 13.21%,respectively.Largest total lipid and AA volumetric production rate obtained under the condition of the 1.0 m M Na NO3,were 216.39 mg·L-1·d^-1?2.5 cm light-path?and 21.65 mg·L-1·d^-1?6.0 cm light-path?.4.The different light-path?1.5 cm,3.0 cmand5.0 cm light-path?of flat flate photobioreactor had the significantly influence on he growth,total lipid and arachidonic acid accumulation of P.incisa under two different Na NO3 nitrogen concentrations in 300 ?mol·m^-2·s^-1 light intensity.Among them,the biggest biomass of P.incisa,in the 1.5 cm light-path?17.6 m M Na NO3?and 3.0 cm light-path?17.6m M Na NO3?,were 2.93 g·L-1 and 2.98 g·L-1.The biggest total lipid contents of three kinds of light-path?5.0 cm,3.0 cm and 1.5 cm?of flat plate photobioreactors under the condition of 1.0 m M Na NO3 were 40.74%,39.17% and 37.23% respectively,and there was no significant difference.Biggest AA content was 11.33% in 5.0 cm light-path of flat flate photobiorector and 1.0 m M Na NO3 condition.The biggest total lipid volumetric production rate in flat flate photobioreactor?1.5 cm?were 135.03mg·L-1d^-1?17.6 m M?and 135.93 mg·L-1d^-1?1.0 m M?.Biggest AA volumetric production rate was 19.42 mg·L-1·d^-1 in 5.0 cm light-path of flat plate photobioreactor and 1.0 m M Na NO3 condition.5.There had the significant effect of the height of column,light intesity and culture density on the growth of P.incisa on the new photobioreactor.The largest net production rate was 19.53 g m^-2d^-1 of P.incisa under 2.5 mm high column,culture density OD750 = 0.6,the light intensity of 400 ?mol·m^-2·s^-1 by using the new photobioreactor for 10 d.6.T.elongatus was cultivited in different temperture?35 ?,45 ?,55 ??and culture density?culture OD730=0.2;0.4;0.6?.The results showed that the highestbiomass and culture OD730 all obtained in 45?,were 1.69 g·L-1?culture OD730=0.2?,1.74 g·L-1?culture OD730=0.4?and 1.73 g·L-1?culture OD730=0.6?and 4.61,4.85 and4.77 respectively.T.elongatus cultived for four days had the highest net production rate(69.62 g·m^-2·d^-1)on the new photobioreactor?0.485 m×0.185 m?used outdoors with 5.0 mm high column.When T.elongatus was cultivated on the new photobioreactor?1.5m×0.5 m?used outdoors with 10.0 mm high column and culture density OD730=1.2 condition,there had the largest net production rate was 48.63g·m^-2·d^-1.