Identification of carotenoids and chlorophylls from green algae Chlorococcum humicola and extraction by liquefied dimethyl ether

In this study, the microalga Chlorococum humicula was evaluated as a potential source of carotenoids and chlorophylls, and extraction of these pigments with liquefied dimethyl ether (DME) as an alternative green solvent was investigated. Carotenoids and chlorophylls in the algae were identified by spectral and comparative band ratio analyses. The liquefied DME extraction was shown to be a rather fast process for the extraction of pigments from C. humicula at relatively high yields. The effects of the extraction solvent: sample ratio, time, and temperature in the liquefied DME extraction of C. humicola on the yields of neoxanthin, violaxanthin, lutein, chlorophyll-b, chlorophyll-a, as well as the total carotenoids and chlorophylls, were determined. The highest total carotenoids yield (4.14 mg/g dry weight algae) and total chlorophylls yield (8.45 mg/g dry weight algae) were obtained using a 45:1 (w/w) liquefied DME: algae wet weight ratio for 20 min at 41 degrees C. At this condition, extraction of 91 % and 35 % of the total carotenoids and chlorophylls, respectively, was attained. In contrast, the extraction yield and percentage recovery of carotenoids obtained with acetone, a conventional solvent, was found to be lower than that of the liquefied DME, suggesting that liquefied DME has a higher selectivity for the less polar carotenoids than that of acetone. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.