CHEMICAL ENGINEERING TRANSACTIONS VOL. 52, 2016 A publication of The Italian Association of Chemical Engineering Online at www.aidic.it/cet Guest Editors: Petar Sabev Varbanov, Peng-Yen Liew, Jun-Yow Yong, Jiří Jaromír Klemeš, Hon Loong Lam Copyright © 2016, AIDIC Servizi S.r.l., ISBN 978-88-95608-42-6; ISSN 2283-9216 Life Cycle Analysis of Microalgae Extraction Techniques Sofia G. Papadaki, Kontastina E. Kyriakopoulou, Magdalini K. Krokida School of Chemical Engineering, National Technical University of Athens, Zografou Campus, Athens, GR-15700, Greece spcheng@central.ntua.gr In this study, a comparative analysis between conventional solvent extraction and innovative green extraction methods, using microwaves and ultrasounds, has been conducted for the recovery of bioactive compounds and especially astaxanthin from Haematococcus pluvialis microalga. The isolation of the desired natural compounds as well as the environmental impact of each method has been the criteria for the different processes evaluation. A comparative life cycle analysis was carried out, using proper databases and software, in order to evaluate the selected extraction processes’ sustainability. Among the extraction procedures applied, ultrasound assisted extraction was found the most sustainable method so far for astaxanthin extraction, regarding its high yielding, low cost, short time and medium environmental impact. Moreover, microwave assisted extraction showed great potential as a rapid and overall eco-friendly technique suffering though from low yielding due to thermal degradation of carotenoids in long processing times. 1. Introduction The green algae Haematococcus pluvialis (H. pluvialis) is a freshwater species of Chlorophyta from the family Haematococcaceae. During unfavorable growth conditions, H. pluvialis initiates carotenogenesis while undergoes morphological transformation from green vegetative cells to deep red (Galvão et al., 2013). The most abundant carotenoid in H. pluvialis is astaxanthin that can reach high concentration more than 4 % of dry weight (Miao et al., 2006). This carotenoid possesses various pharmacological activities, including antioxidant activity antitumor effects antidiabetic and anti-inflammatory properties. Astaxanthin-rich Haematococcus has already been marketed as a dietary supplement for human consumption. The health benefit of this product is mainly due to its strong antioxidant activity, which is 100 times more than a-tocopherol. Moreover, astaxanthin has an antioxidant action up to 500 times that of vitamin E and is the most stable antioxidant and never turns into a pro-oxidant. In addition, pro-vitamin A, a more effective antioxidant that other carotenoids, decelerate age-related macular degeneration, immunomodulatory effects, etc. (Guerin et al., 2003). The range of shades from astaxanthin includes red as well as orange. Therefore, it can replace synthetic ones such as Tartrazine, Sunset Yellow etc. Moreover, the significant antioxidant activity that astaxanthin presents can sufficiently compete and replace synthetic antioxidants such as BHA, BHT (Kyriakopoulou et al., 2013). For the effective utilization of astaxanthin, the nutrient should be extracted from the microalga. The increasing legislative restrictions on the presence of organic solvents in food products coupled to their negative effects on the nutritional and functional properties of compounds such as carotenoids have driven the search for “greener” alternatives than acetone, which is commonly used to extract valuable lipophilic compounds from microalgae. In addition, nowadays, conventional extraction methods tend to be replaced due to the several disadvantages such as energy usage, solvent consumption, time, etc. Ultrasound Assisted Extraction (UAE) and Microwave Assisted Extraction (MAE) are two proposed green extraction method for the recovery of astaxanthin. In this study, a comparative analysis between conventional solvent extraction and innovative green extraction methods, using microwaves and ultrasounds, has been conducted for the recovery of astaxanthin from H. pluvialis. The isolation of the desired natural compounds as well as the environmental impact of each method has been the criteria for the different processes evaluation. A comparative life cycle analysis was carried out, using proper databases and software, in order to evaluate the selected extraction processes’ sustainability. DOI: 10.3303/CET1652174 Please cite this article as: Papadaki S. G., Kyriakopoulou K. E., Krokida M. K., 2016, Life cycle analysis of microalgae extraction techniques, Chemical Engineering Transactions, 52, 1039-1044 DOI:10.3303/CET1652174 1039