Biosynthesis of highly unsaturated fatty acids by hydrocarbon degrading microorganisms
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Date
2015-03-08
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Plovdiv University Press “Paisii Hilendarski”
Abstract
Disruption of polyunsaturated fatty acids (PUFA) metabolism leads to many diseases. In this study, producers of γ-linolenic acid (GLA), arachidonic acid (ARA) and eicosapentaenoic acid (EPA) were selected: Cephalosporium humicola IE (on glucose, dry biomass – 14 g/l, total lipids – 18-20%, GLA in lipids – 12.0%), Mucor globosus 11 (respectively – 15 g/l, 18% and 5%) and Pythium irregulare LX (on glucose, dry biomass – 14.5 g/l, total lipids – 18-20%, 9.2 and 7.8% of ARA and EPA, respectively). On crude oil as the only source of carbon, the amount of biomass of the specified fungi decreases by 3-4 times, whereas the quantity of lipids and highly unsaturated fatty acids increases in four and 1.2 - 3.4 times, respectively. The maximum γ-linolenic acid in M. globosus and C. humicola was detected at neutral рН. Optimum volume of inoculate was 2.0-4.0%, nitrogen source NH4NO3, a carbon-nitrogen ratio 34:1. For biosynthesis of ARA and EPA by P. irregulare, the optimum nitrogen source was NH4Cl, рН 7.0- 8.0 and С/N - 50:1 at 28°C. The process of adaptation to stressful situation under crude oil motivated the increase of the rate of membrane phospholipids with high quantity of unsaturated fatty acids.
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Cephalosporium humicola, Mucor globosus, Pythium irregulare, single cell oils, polyunsaturated fatty acids, omega, optimization