Review Review of feedstock pretreatment strategies for improved anaerobic digestion: From lab-scale research to full-scale application Hélène Carrere a,⇑ , Georgia Antonopoulou b , Rim Affes a , Fabiana Passos c,d , Audrey Battimelli a , Gerasimos Lyberatos b,e , Ivet Ferrer c a INRA, UR0050, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, 11 100 Narbonne, France b Institute of Chemical Engineering Sciences, Stadiou, Platani, GR 26504 Patras, Greece c GEMMA – Environmental Engineering and Microbiology Research Group, Department of Hydraulic, Maritime and Environmental Engineering, Universitat Politècnica de CatalunyaBarcelonaTech, c/Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain d Environmental and Chemical Technology Group, Department of Chemistry, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil e School of Chemical Engineering, National Technical University of Athens, GR 15780 Athens, Greece highlights  Guidelines on the most appropriate pretreatments for the main biogas feedstocks.  Sludge pretreatment with steam explosion is most recommended, already at full-scale.  Fatty residues saponification is preferred, with animal by-products sterilization.  For lignocellulosic biomass alkali or biological pretreatments are most promising.  Microalgae thermal pretreatment seems most promising so far. graphical abstract article info Article history: Received 6 July 2015 Received in revised form 4 September 2015 Accepted 5 September 2015 Available online xxxx Keywords: Algae Anaerobic biodegradability Animal by-products Lignocellulosic biomass Sewage sludge abstract When properly designed, pretreatments may enhance the methane potential and/or anaerobic digestion rate, improving digester performance. This paper aims at providing some guidelines on the most appro- priate pretreatments for the main feedstocks of biogas plants. Waste activated sludge was firstly inves- tigated and implemented at full-scale, its thermal pretreatment with steam explosion being most recommended as it increases the methane potential and digestion rate, ensures sludge sanitation and the heat needed is produced on-site. Regarding fatty residues, saponification is preferred for enhancing their solubilisation and bioavailability. In the case of animal by-products, this pretreatment can be opti- mised to ensure sterilisation, solubilisation and to reduce inhibition linked to long chain fatty acids. With regards to lignocellulosic biomass, the first goal should be delignification, followed by hemicellulose and cellulose hydrolysis, alkali or biological (fungi) pretreatments being most promising. As far as microalgae are concerned, thermal pretreatment seems the most promising technique so far. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction The Web of Science Ò shows an increasing number of published papers per year with ‘‘anaerobic digestion” and ‘‘pretreatment” as http://dx.doi.org/10.1016/j.biortech.2015.09.007 0960-8524/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +33 468 425 168; fax: + 33 468 425 160. E-mail address: helene.carrere@supagro.inra.fr (H. Carrere). Bioresource Technology xxx (2015) xxx–xxx Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech Please cite this article in press as: Carrere, H., et al. Review of feedstock pretreatment strategies for improved anaerobic digestion: From lab-scale research to full-scale application. Bioresour. Technol. (2015), http://dx.doi.org/10.1016/j.biortech.2015.09.007