title: Estimation of neutral lipid and carbohydrate quotas in microalgae using adaptive interval observers.
abstract: Under stress conditions, microalgae are known to accumulate large amounts of neutral lipids and carbohydrates, which can be used for biofuel production. However, on-line measurement of microalgal biochemical composition is a difficult task which makes the microalgal process rather difficult to manage. In this paper, we propose a so called adaptive interval observer for the on-line estimation of neutral lipid and carbohydrate quotas in microalgae. The observer is based on a change of coordinates that involves a time-varying gain. We introduce dynamics for the gain, whose trajectory converges toward a predefined optimal value (which maximizes the convergence rate of the observer). The observer performance is illustrated with experimental data of Isochrysis sp. cultures under nitrogen limitations and day-night cycle. The proposed observer design appears to be a suitable robust estimation technique.
authors: Departamento de Matemática, Universidad Técnica Federico Santa María, Avda España 1680, Valparaiso, Chile, francis.mairet@usm.cl.
authors: Francis
authors: F
authors: Mairet
authors: Marcelo
authors: M
authors: Moisan
authors: Olivier
authors: O
authors: Bernard
mesh_terms: D000465:Algorithms; D056804:Biofuels; D018533:Biomass; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry*; D018929:Cell Culture Techniques / Q000379:methods; D005285:Fermentation; D058087:Haptophyta; D008027:Light; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry*; D058086:Microalgae / Q000378:metabolism*; D009584:Nitrogen / Q000737:chemistry; D009862:Online Systems; D012107:Research Design; D013312:Stress, Physiological; D013997:Time Factors
chemical_list: D056804:Biofuels; D002241:Carbohydrates; D008055:Lipids; D009584:Nitrogen