New Biotechnology  Volume 32, Number 3  May 2015 RESEARCH PAPER Dual purpose system that treats anaerobic effluents from pig waste and produce Neochloris oleoabundans as lipid rich biomass Eugenia J. Olguı´n, Omar S. Castillo, Anilu ´ Mendoza, Karla Tapia, Ricardo E. Gonza ´ lez-Portela and Vı ´ctor J. Herna ´ ndez-Landa Environmental Biotechnology Group, Institute of Ecology (INECOL), Carretera Antigua a Coatepec No. 351, Xalapa 91070, Veracruz, Mexico Abstract Dual purpose systems that treat wastewater and produce lipid rich microalgae biomass have been indicated as an option with great potential for production of biodiesel at a competitive cost. The aim of the present work was to develop a dual purpose system for the treatment of the anaerobic efﬂuents from pig waste utilizing Neochloris oleoabundans and to evaluate its growth, lipid content and lipid proﬁle of the harvested biomass and the removal of nutrients from the media. Cultures of N. oleoabundans were established in 4 L ﬂat plate photobioreactors using diluted efﬂuents from two different types of anaerobic ﬁlters, one packed with ceramic material (D1) and another one packed with volcanic gravel (D2). Maximum biomass concentration in D1 was 0.63 g L 1 which was signiﬁcantly higher than the one found in D2 (0.55 g L 1 ). Cultures were very efﬁcient at nutrient removal: 98% for N–NH 4 + and 98% for PO 4 3 . Regarding total lipid content, diluted eﬂluents from D2 promoted a biomass containing 27.4% (dry weight) and D1 a biomass containing 22.4% (dry weight). Maximum lipid productivity was also higher in D2 compared to D1 (6.27  0.62 mg L 1 d 1 vs. 5.12  0.12 mg L 1 d 1 ). Concerning the FAMEs proﬁle in diluted efﬂuents, the most abundant one was C18:1, followed by C18:2 and C16:0. The proﬁle in D2 contained less C18:3 (linolenic acid) than the one in D1 (4.37% vs. 5.55%). In conclusion, this is the ﬁrst report demonstrating that cultures of N. oleoabundans treating anaerobic efﬂuents from pig waste are very efﬁcient at nutrient removal and a biomass rich in lipids can be recovered. The maximum total lipid content and the most convenient FAMEs proﬁle were obtained using efﬂuents from a digester packed with volcanic gravel. Introduction Microalgae have been considered as a potential raw material for the production of biofuels such as biodiesel, bioethanol, bio- methane and biohydrogen [1,2]. However, several recent reports have indicated that there are various technological, market and policy constraints that need to be overcome in order to develop economically feasible processes for the production of biofuels from microalgae. Furthermore, recent studies involving the use of Life Cycle Analysis have indicated that the use of wastewater as source of water and nutrients for the cultivation of microalgae could contribute strongly to decrease the cost of microalgae production. It is within this context, that dual purpose systems for the treat- ment of wastewater and production of valuable microalgae bio- mass have been proposed as one of the main strategies for the production of biodiesel from microalgae at a competitive cost [3]. On the other hand, pig manure is one of the most polluting wastes because of its high organic matter concentration, in terms Research Paper Corresponding author. Tel.: +52 2288 42 18 48. Olguı ´n, E.J. (eugenia.olguin@inecol.mx, genaolguin@yahoo.com.mx) http://dx.doi.org/10.1016/j.nbt.2014.12.004 www.elsevier.com/locate/nbt 1871-6784/ß 2015 Elsevier B.V. All rights reserved. 387