Abstract: In order to maximize arachidonic acid methyl ester production, the methyl esterification of microbial oil was optimized with respect to temperature, reaction time, catalyst (concentrated sulfuric acid) dosage and agitation speed using one-factor-a-at-a-time combined with orthogonal array design method. The highest yield of 91.54% was achieved after 8 h of reaction at 80 ℃ and an agitation speed of 400 r/min under the catalysis of 2.0% concentrated sulfuric acid. The obtained product contained 37.75% arachidonic acid methyl ester and its boiling point was lower than before the reaction, facilitating molecular distillation.

Key words: microbial oil, arachidonic acid, methyl esterification