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Effects of mineral addition on the growth morphology of and arachidonic acid production by Mortierella alpina 1S‐4
Author(s) -
Higashiyama Kenichi,
Yaguchi Toshiaki,
Akimoto Kengo,
Fujikawaa Shigeaki,
Shimizu Sakayu
Publication year - 1998
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-998-0336-9
Subject(s) - pellets , fermentation , yield (engineering) , pellet , arachidonic acid , chemistry , morphology (biology) , mycelium , food science , botany , biochemistry , materials science , biology , enzyme , metallurgy , composite material , genetics
Abstract The culture conditions for arachidonic acid (AA) production by Mortierella alpina 1S‐4 were investigated by means of a morphological study with the aims of obtaining a high AA yield and scale‐up. In a 50‐L jar fermentor study, a medium containing 3.1% soy flour and 1.8% glucose with 0.3% KH 2 PO 4 , 0.1% Na 2 SO 4 , 0.05% CaCl 2 ·2H 2 O and 0.05% MgCl 2 ·6H 2 O was found to be optimum. The AA yield reached 9.8 g/L/7 d, and the major morphology was small pellets (1–2 mm). However, in the case of the only addition of KH 2 PO 4 , the major morphology was filaments. The apparent viscosity increased to 2240 cp, thereby requiring a high agitation speed to maintain adequate oxygen tension, which caused mycelial damage due to shear stress and therefore a decrease in the AA yield. When a medium with Na 2 SO 4 , CaCl 2 , and MgCl 2 was used, the major morphology was large pellets (2–3 mm), and mass transfer limitation through the pellet wall caused a decrease in the AA yield. Based on these results, a scale‐up study was carried out under the optimal conditions described above. An AA yield of 10.9 g/L/8 d was obtained in a 10‐kL industrial fermentor, and the major morphology was small pellets.