Influence of medium components and pH on the production of odd-carbon fatty acids by Aurantiochytrium sp. SA-96

Abstract

Odd-carbon fatty acids have been utilized for anaplerotic therapy for lifestyle-related diseases such as Alzheimer’s disease and diabetes. We examined the culture condition of Aurantiochytrium for the production of pentadecanoic acid (C15) as an odd-carbon fatty acid, and demonstrated a produce method for odd-carbon fatty acid–enriched triglyceride. To determine the optimum conditions for C15 production, selection of effective components and their respective concentrations in the culture medium, choice of the suitable Aurantiochytrium strain, and determination of the optimum culture pH were performed.

The optimum conditions for the production of C15 were found to be as follows:

Strain: Aurantiochytrium sp. strain SA-96

Medium composition: 0.2% yeast extract 0.5% monosodium glutamate, 1.0% sea salt, 50 mM L-Val, 25 mM sodium propionate, 3.6% glucose, and 10% soy milk whey.

Culture system: Airlift culture vessels (5.0 L) and pH controller were used. Sodium hydroxide (1.0 M) solution was used for pH adjustment. Other parameters were as follows: medium volume, 3.0 L; air supply, 1.2 vvm; temperature, 23.5–26.6 °C; pH, 7.40–7.74; culture period, 72 h.

The yield of odd-carbon fatty acids (C15, 85% of odd FA) was 1.04 g L⁻¹.

Preparation of odd-carbon fatty acid–enriched triglyceride: Triglyceride was isolated from the extracted lipids from cultured cells and treated with ozone/hydrogen peroxide. By removing of carboxylic acid containing triglyceride, the odd-carbon fatty acid and C15 contents of the resultant triglyceride reached to 72.3 and 60.7%, respectively.