Development of an Efficient Extraction Method for Harvesting Gymnodimine-A from Large-Scale Cultures of Karenia selliformis

• Published in: Toxins 2021-11, Vol.13 (11), p.793
• Main Authors: Tang, Zhixuan, Qiu, Jiangbing, Wang, Guixiang, Ji, Ying, Hess, Philipp, Li, Aifeng
• Format: Article
• Language: English
• Subjects: Algae; Aquatic microorganisms; Cell culture; Centrifugation; Culture media; Dichloromethane; Dinoflagellida - metabolism; extraction method; Filtration; gymnodimine; Heterocyclic Compounds, 3-Ring - metabolism; Hydrocarbons, Cyclic - metabolism; Imines - metabolism; Karenia; Karenia selliformis; Life Sciences; Liquid-liquid extraction; liquid-liquid extraction (LLE); Liquid-Liquid Extraction - methods; Marine Toxins - metabolism; Microalgae; Microorganisms; pH effects; Quotas; Recovery; Reference materials; Shellfish; Toxins
• ISSN: 2072-6651; 2072-6651
• DOI: 10.3390/toxins13110793

Gymnodimine-A (GYM-A) is a fast-acting microalgal toxin and its production of certified materials requires an efficient harvesting technology from the large-scale cultures of toxigenic microalgae. In this study the recoveries of GYM-A were compared between several liquid-liquid extraction (LLE) treatments including solvents, ratios and stirring times to optimize the LLE technique for harvesting GYM-A from cultures, of which the dichloromethane was selected as the extractant and added to microalgal cultures at the ratio 55 mL L (5.5%, / ). The recovery of GYM-A obtained by the LLE technique was also compared with filtration and centrifugation methods. The stability of GYM-A in culture media were also tested under different pH conditions. Results showed that both the conventional filter filtration and centrifugation methods led to fragmentation of microalgal cells and loss of GYM-A in the harvesting processes. A total of 5.1 µg of GYM-A were obtained from 2 L of cultures with a satisfactory recovery of 88%. Interestingly, GYM-A obviously degraded in the culture media with the initial pH 8.2 and the adjusted pH of 7.0 after 7 days, but there was no obvious degradation in the acidic medium at pH 5.0. Therefore, the LLE method developed here permits the collection of large-volume cultures of and the high-efficiency extraction of GYM-A. This work provides a simple and valuable technique for harvesting toxins from large-scale cultures of GYM-producing microalgae.