Fermentation Conditions and Media Optimization for Isocitric Acid Production from Ethanol by Yarrowia lipolytica

• Published in: BioMed research international 2018-01, Vol.2018 (2018), p.1-9
• Main Authors: Morgunov, Igor G., Allayarov, Ramil K., Lunina, Julia N., Morgunov, Grigorii I., Stepanova, Nadezda N., Shamin, Roman V., Kamzolova, Svetlana V., Samoilenko, Vladimir A.
• Format: Article
• Language: English
• Subjects: Acid production; Acids; Aeration; Alcohol; Alcohol, Denatured; Baking yeast; Biochemistry; Biotechnology; Carbon; Chemical synthesis; Citric Acid Cycle; Cultivation; Culture media; Culture Media - chemistry; Diastereomers; Energy; Ethanol; Ethanol - chemistry; Ethanol - metabolism; Fermentation; Hydrogen ions; Hypoxia; Iron; Isocitrate lyase; Isocitrate Lyase - chemistry; Isocitrates - chemistry; Isocitric acid; Itaconic acid; Kinases; Krebs cycle; Lipids; Metabolism; Metabolites; Microbiology; Microorganisms; Nutrient content; Nutrition; Optimization; Oxygen - chemistry; pH effects; Physiological aspects; Production processes; Respiration; Saccharomyces cerevisiae; Saturation; Stereoisomerism; Stereoisomers; Temperature effects; Tricarboxylic acid cycle; Yarrowia - chemistry; Yarrowia lipolytica; Zinc
• ISSN: 2314-6133; 2314-6141
• DOI: 10.1155/2018/2543210

Isocitric acid exists in the form of four stereoisomers, of which only the threo-Ds-form (ICA) is a natural active compound, an intermediate of Krebs cycle, and suitable for nutritional and pharmaceutical use. In this paper, we propose a method for ICA production from ethanol by yeast Yarrowia lipolytica. The effects of temperature, pH of the medium, and aeration on the growth of the producer Y. lipolytica VKM Y-2373 and synthesis of ICA were studied. An optimal fermentation regime, which ensures a good growth of the producer and directed synthesis of the target product, was determined. The producer is advised to carry out cultivation at 29°C and various pH of the medium and the oxygen concentration (pH 5 and pO2 20–25% (of saturation) during the growth period and pH 6 and pO2 50–55% (of saturation) during the acid formation) on a nutrient medium containing an increased content of zinc (0.6 mg/L), iron (1.2 mg/L), and 30 mM itaconic acid (inhibitor of isocitrate lyase—the key enzyme of ICA metabolism) should also be introduced into the nutrition medium. Such fermentation production mode provides 90.5 g/L ICA with process selectivity of 80%, mass yield (YICA) of 0.77 g/g, and energy yield (ηICA) of 0.278 g/g.