Recovery of pigments from Ulva rigida

Abstract

Pigments, such as chlorophylls and carotenoids, have important applications in various fields, such as colorants in food, cosmetic or textile industries and in biomedical applications. Both pigments have an important role in the photosynthetic process and can be found in the marine green macroalgae genus Ulva. In this work, an integrated downstream process was developed to extract chlorophylls and carotenoids from those macroalgae. The solid-liquid extraction was optimized. For that, several conditions were tested, namely the use of different mechanical processes (maceration, microwave- or ultrasound- assisted extraction), type of solvent, number of consecutive extractions, solid-liquid ratio, and the design of the extraction process using a mechanical treatment. Using the extract obtained, a liquid-liquid extraction system composed of ethanol, hexane, and water was then studied. Different mixture points within the biphasic region were tested in terms of their ability to selectively separate chlorophylls and xanthophylls to opposite phases in a single step. The optimization and implementation of a simple, fast and efficient downstream process to separate both classes of pigments such as chlorophylls and xanthophylls from green macroalgae is reported. It could be applied to fractionate other extracts with similar compositions obtained from other natural sources.