Optimization of arachidonic acid production by Mortierella alpina Wuji‐H4 isolate

Abstract

A fungal isolate Wuji-H4 with a dense-lobe rosette growth pattern on malt extract agar was identified as Mortierella alpina Peyronel. It was capable of producing 504 mg/L of arachidonic acid (AA) in the screening medium. Its AA content accounted for 42.4% of the total fatty acids. The AA yield was raised to 1,817 mg/L by a step-by-step approach, which uncovered that the preferred carbon source, nitrogen source, and temperature for fungal growth and lipid production were soluble starch, urea, and 24°C, respectively. Productivity was further optimized by exploiting the interactions between the constituents of the medium by the response surface method. A partial factorial design, followed by steepest ascent analysis, was carried out to locate the general vicinity of the optimal level of each nutrient. The response surface of AA production in this optimal region was then approximated with a full quadratic equation obtained from a three-factor/five-level central composite rotatable design. Maximum AA yield was predicted to occur in a medium that contained 99.7 g/L of soluble starch, 12.6 g/L of yeast extract, and 3.0 g/L of KH 2 PO 4 . Upon verification, the average experimental yield of AA (3,885 mg/L) was not significantly different from the predicted AA yield (3,940 mg/L), indicating that the response surface method had succeeded in exploiting the AA production potential of this new fungal isolate. JAOCS 74, 569-578 (1997).

High-level production of arachidonic acid by fed-batch culture of Mortierella alpina using NH4OH as a nitrogen source and pH control

“…ARA production using M. alpina has been studied in batch and fed-batch operations with various fermentation scales, which have shown final ARA concentration in the ranges between 3-13 g l )1 (Li et al 1995, Chen et al 1997, Higashiyama et al 1998, 2002, Eroshin et al 2000. The ARA productivity was affected by many factors, such as cell morphology, carbon and nitrogen sources, mineral addition, and dissolved oxygen concentration.…”

“…The ARA productivity was affected by many factors, such as cell morphology, carbon and nitrogen sources, mineral addition, and dissolved oxygen concentration. (Bajpai et al 1991, Chen et al 1997, Higashiyama et al 1998, 2002, Park et al 1999. For the intracellular product of ARA, achievement of high biomass cultivation is desirable to improve ARA productivity.…”

An inexpensive medium for production of arachidonic acid by Mortierella alpina

“…Thus, there is increasing interest in the microbial production of AA, which has a higher yield and contains fewer impurities. The filamentous fungus Mortierella alpina, belonging to the Phycomycetes class, has been identified as a promising producer of AA [6].…”

Isolation and identification of native lower fungi for polyunsaturated fatty acid (PUFA) production in Thailand, and the effect of carbon and nitrogen sources on growth and production

“…Botha et al (1999) developed an isolation procedure for ARA producing species at low temperature (5°C). Chen et al (1997) screened for low temperature (10°C) ARA producer fungal strains and obtained the Wuji-H4 isolate with high content of ARA (42.4%) in lipids. Shimizu et al (1988) investigated the effect of temperature on the fatty acid composition of Mortierella fungi.…”