Tamene Milkessa Jiru1, Marizeth Groenewald2, Carolina Pohl3, Laurinda Steyn3, Nicholas Kiggundu4, Dawit Abate5. 1. Microbial, Cellular and Molecular Biology Department, College of Natural Science, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia. tamene.milkessa@aau.edu.et. 2. Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, P.O. Box 85167, 3508 AD,, Utrecht, The Netherlands. 3. Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, P.O. Box 339, Bloemfontein, South Africa. 4. Department of Agricultural and Biosystems-Engineering, School of Food Technology, Nutrition and Bio-Engineering, Makerere University, P.O. Box 7062, Kampala, Uganda. 5. Microbial, Cellular and Molecular Biology Department, College of Natural Science, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
Abstract
Rhodotorula kratochvilovae (syn, Rhodosporidium kratochvilovae) SY89, an oleaginous yeast, isolated from Ethiopian soil, was grown under nitrogen-limited media. The capacity this with respect to biomass production, lipid yield and lipid content was evaluated. The influence of inoculum size, carbon sources, variations in glucose concentration, nitrogen sources, C/N ratio, pH, temperature, agitation, and aeration rate and incubation period were investigated. Inoculum size of 10% v/v, glucose as a carbon source at 50 g/L glucose, 0.50 g/L yeast extract and 0.31 g/L (NH4)2SO4, C/N ratio of 120, pH 5.5, incubation temperature of 30 °C, 225 rpm, 0.2 as aeration ratio and 144 h of incubation were found to be optimum conditions for lipid production. Then the yeast was grown in a batch bioreactor by combining the different optimized parameters together. Under the optimized conditions, the yeast gave maximum biomass (15.34 ± 1.47 g/L), lipid yield (8.60 ± 0.81 g/L) and lipid content (56.06 ± 1.70%). The dominant fatty acids exhibited in order of their relative abundance (%w/w), were oleic, palmitic, linoleic, stearic, linolenic and palmitoleic acids. The concentration of saturated and monounsaturated fatty acids adds up 78.63 ± 2.19%. This suggests that this strain could be used as a good feedstock for biodiesel production.
Rhodotorula kratochvilovae (syn, n class="Species">Rhodosporidium kratochvilovae) SY89, an oleaginous yeast, isolated from Ethiopian soil, was grown under nitrogen-limited media. The capacity this with respect to biomass production, lipid yield and lipid content was evaluated. The influence of inoculum size, carbon sources, variations in glucose concentration, nitrogen sources, C/N ratio, pH, temperature, agitation, and aeration rate and incubation period were investigated. Inoculum size of 10% v/v, glucose as a carbon source at 50 g/L glucose, 0.50 g/L yeast extract and 0.31 g/L (NH4)2SO4, C/N ratio of 120, pH 5.5, incubation temperature of 30 °C, 225 rpm, 0.2 as aeration ratio and 144 h of incubation were found to be optimum conditions for lipid production. Then the yeast was grown in a batch bioreactor by combining the different optimized parameters together. Under the optimized conditions, the yeast gave maximum biomass (15.34 ± 1.47 g/L), lipid yield (8.60 ± 0.81 g/L) and lipid content (56.06 ± 1.70%). The dominant fatty acids exhibited in order of their relative abundance (%w/w), were oleic, palmitic, linoleic, stearic, linolenic and palmitoleic acids. The concentration of saturated and monounsaturated fatty acids adds up 78.63 ± 2.19%. This suggests that this strain could be used as a good feedstock for biodiesel production.
Authors: Martin Szotkowski; Jiří Holub; Samuel Šimanský; Klára Hubačová; Pavlína Sikorová; Veronika Mariničová; Andrea Němcová; Ivana Márová Journal: Microorganisms Date: 2021-05-28
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