Improvement of arachidonic acid production by mutants with lower n-3 desaturation activity derived from Mortierella alpina.
Five mutants were obtained, Y11, Y135, Y164, Y180 and Y61, capable of accumulating higher amounts of arachidonic acid (AA) than Mortierella alpina 1S-4, an industrial strain for the production of AA-rich triacylglycerol (TG). This is thought to be due to low or no activity of n-3 desaturation with conversion of AA to eicosapentaenoic acid, which functions at a cultural temperature below 20 degrees C. In small-scale cultivation under optimum conditions, Y11 and Y61 respectively accumulated 4.97 mg/ml and 4.11 mg/ml of AA, using a high concentration of glucose at 20 degrees C, compared with 3.74 mg/ml for M. alpina 1S-4. In a 5-1 jar fermentor, the AA content in Y11 and Y61 kept increasing during cultivation, with consumption of the glucose in the medium; and this reached 1.48 mg/ml and 1.77 mg/ml (118 mg/g, 120 mg/g of dry mycelia) at day 10, respectively, compared with 0.95 mg/ml (86 mg/g of dry mycelia) for M. alpina 1S-4. From the results of lipid analysis, the TG contents of Y11 and Y61 in the major lipids were significantly higher than that of M. alpina 1S-4; and the AA percentages in TG of Y11 and Y61 were also higher. Both Y11 and Y61 are potential producers of TG rich in AA.
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto, 606-8502, Japan.
Eiji
E
Sakuradani
Yuriko
Y
Hirano
Nozomu
N
Kamada
Masutoshi
M
Nojiri
Jun
J
Ogawa
Sakayu
S
Shimizu
D001095:Arachidonic Acids / Q000096:biosynthesis*; D044943:Fatty Acid Desaturases / Q000502:physiology*; D005947:Glucose / Q000378:metabolism; D020094:Mortierella / Q000254:growth & development / Q000378:metabolism*; D009154:Mutation; D013696:Temperature; D014280:Triglycerides / Q000096:biosynthesis
D001095:Arachidonic Acids; D014280:Triglycerides; D044943:Fatty Acid Desaturases; D005947:Glucose