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.
Sakuradani
Eiji
E
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto, 606-8502, Japan.
Hirano
Yuriko
Y
Kamada
Nozomu
N
Nojiri
Masutoshi
M
Ogawa
Jun
J
Shimizu
Sakayu
S
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