Physicalechemical characteristics of lignins separated from biomasses for second-generation ethanol Davide Savy, Alessandro Piccolo* Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l’Ambiente, l’Agro-Alimentare ed i Nuovi Materiali (CERMANU), Universita ` di Napoli Federico II, Via Universita ` 100, 80055 Portici, Italy article info Article history: Received 19 August 2013 Received in revised form 13 January 2014 Accepted 17 January 2014 Available online xxx Keywords: Biomass for energy Lignin extraction Lignin solubility NMR TGA HPSEC abstract Lignin was extracted by two extraction methods from two biomasses for energy (Mis- chantus and Giant Reed) and a lignocellulosic material resulting from a microbial treat- ment of giant reed. One method of extraction involved the use of H 2 SO 4 (SA), providing a highly aromatic water-insoluble material, while a second method employed H 2 O 2 at alkaline pH (Ox), resulting in a water-soluble lignin. Extraction yields were related to the total Klason lignin measured for the three materials. We compared the physicalechemical features of the isolated lignins, by employing solid-state nuclear magnetic resonance spectroscopy ( 13 C-CPMAS spectra and derived T1rH relaxation times), thermogravimetric analyses, infrared spectrometry and high performance size exclusion chromatography (HPSEC). We found that lignin separated by the Ox method owned a more mobile molecular conformation, and was largely more water-soluble and fragmented than the lignin ob- tained by the SA treatment. In line with T1rH-NMR and thermogravimetric results, the HPSEC of Ox lignins showed nominal molecular weights less than 3 kDa, indicating well depolymerized materials. Such low-molecular weight and fragmented lignin obtained from biomasses for energy may become useful for application of recycled products in agriculture and in green chemistry reactions, thereby promoting an increase in the economic sus- tainability of biorefineries. ª 2014 Published by Elsevier Ltd. 1. Introduction Plant biomasses rich in lignocellulose represent the largest renewable source of hexose and pentose sugars for potential conversion in either ethanol for fuels or various chemicals for industry [1]. First-generation ethanol has been massively ob- tained from food crops such as wheat and maize [2,3], with consequent reduction of food for animal and human nutrition [1] and overexploitation of valuable productive soil [4]. In order to correct such an unsustainable approach, a second- generation ethanol is now planned to be obtained from non- food biomasses rich in lignocellulose [5,6], and easily grown on marginal soils [7]. Examples of such biomasses are the perennial rhizomatous herbaceous plants, such as miscanthus (Miscanthus  Giganteus, Greef et Deuter) in cool and humid areas, and giant reed (Arundo donax, L.) in warm and dry zones. Both these grasses exhibit high productivity and favorable energy balance even at low nutrient and energy inputs [8e10]. Since no sowing or tillage is required, cultivation of these * Corresponding author. Tel.: þ39 (0) 81 25301 60; fax: þ39 (0) 81 32176. E-mail address: alessandro.piccolo@unina.it (A. Piccolo). Available online at www.sciencedirect.com ScienceDirect http://www.elsevier.com/locate/biombioe biomass and bioenergy xxx (2014) 1 e10 Please cite this article in press as: Savy D, Piccolo A, Physicalechemical characteristics of lignins separated from biomasses for second-generation ethanol, Biomass and Bioenergy (2014), http://dx.doi.org/10.1016/j.biombioe.2014.01.016 0961-9534/$ e see front matter ª 2014 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.biombioe.2014.01.016