No abstract

In this article, to increase the extraction efficiency and quality of single-cell oil (SCO) from Mortierella isabellina NTG 1-121 (MIN) in the SCO extraction, ultrasound in combination with microwave was applied. The best extraction conditions (microwave power 400 W; microwave time 3.7 min; ultrasonic time 40.5 min; ultrasonic power 500 W; and the material to solvent ratio 1:12.3 [w/v]) were achieved at room temperature of 25 AE5 C, using response surface methodology (RSM). Under these conditions, the extraction yield of SCO was up to 92.24% and the SCO yield was 178.13 AE0.17 mg g −1 (wet cell). Compared with ultrasound-assisted extraction (UAE) and acid-heating extraction (AHE), the quality and yield of SCO obtained using the ultrasonic-assisted/microwaveassisted extraction (UMAE) were improved. The present study suggests that UMAE can be an alternative for the extraction of SCO from MIN. The oil is rich in oleic acid (ca. 43.98%), linoleic acid (ca. 11.56%), and gamma linolenic acid (ca. 11.38%), which is comparable to the fatty-acid composition of several edible oils.

In the paper, in order to improve the polyunsaturated fatty acids (PUFAs) by Mortierella isabellina, the effects of carbon source, nitrogen source, carbon to nitrogen (C/N) ratio, and metal ions on PUFAs production were investigated. The results of the research showed that different kinds of carbon source and nitrogen source had obviously effect on PUFAs production, the glucose and mixture nitrogen (yeast extract: peanut meal at 3:1 (w/w)) were greatly suitable for PUFAs production and cell growth. The glucose concentration and C/N ratios have significant effect on PUFAs production. Meanwhile, the results indicate the metal ions have profound effects on fungus growth and PUFAs production. Ca 2+ and Mg 2+ could promote PUFAs production. Almost all the improvement of PUFAs was obtained through increasing thallus biomass, though there were some influences on the metabolism. Under the optimal culture media composition, the yields of cell dry weight, linoleic acid (LA), gama-linolenic acid (GLA), and total PUFAs were 32.48, 2.90, 2.83, and 7.36 g/L, respectively.