12 pages, 5 figures, 8 tablesSeveral compounds with enhanced functional properties of interest in the nutraceutical and medical sectors can be recovered by using the biomass currently wasted in fishing extractive and processing activities, promoting the sustainability of this sector and leading to its development under a bio-economical framework. In particular, it has been observed that crustaceans are an important fraction of the total biomass discarded by fisheries, mainly in those metiers involving coastal waters. Crustacean biomass can be destined to the production of chitin/chitosan (in combination with food use of muscle or protein hydrolysates production) since their exoskeletons are one of the most important sources of this polysaccharide available for commercial use. In this work, the sustainability of both the chemical and enzymatic process to obtain chitin at pilot scale was analysed. The three sustainability dimensions were evaluated and integrated by hierarchical methods to provide a consistent comparison baseline between processes. The results indicated that the enzymatic process could be an adequate alternative that should be considered for chitin extraction, especially if water recovery is employedThe authors acknowledge the financial support received from the European Union through the LIFE Environment Program of the European Union (LIFE05 ENV/E000267-BE FAIR, LIFE08 ENV/E/000119-FAROS, LIFE13 ENV/ES/000131-iSEAS). Carla Lopes thanks the financial support received from the Fundação para a Ciência e a Tecnologia (FCT, Portugal) through the grant SFRH/BD/78626/2011. Luis T. Antelo and Amaya Franco-Uría would like to thank Secretaría de Estado de Investigación, Desarrollo e Innovación for the support provided by the “Ramón y Cajal” Subprogram. Amaya Franco-Uría belongs to the Galician Competitive Research Group GRC 2013-032, program co-funded by ERDF, and to CRETUS (AGRUP2015/02)Peer reviewe

Chondroitin sulfate (CS) is a glycosaminoglycan actively researched for pharmaceutical, nutraceutical and tissue engineering applications. CS extracted from marine animals displays different features from common terrestrial sources, resulting in distinct properties, such as anti-viral and anti-metastatic. Therefore, exploration of undescribed marine species holds potential to expand the possibilities of currently-known CS. Accordingly, we have studied for the first time the production and characterization of CS from blackmouth catshark (Galeus melastomus), a shark species commonly discarded as by-catch. The process of CS purification consists of cartilage hydrolysis with alcalase, followed by two different chemical treatments and ending with membrane purification. All steps were optimized by response surface methodology. According to this, the best conditions for cartilage proteolysis were established at 52.9 °C and pH = 7.31. Subsequent purification by either alkaline treatment or hydroalcoholic alkaline precipitation yielded CS with purities of 81.2%, 82.3% and 97.4% respectively, after 30-kDa membrane separation. The molecular weight of CS obtained ranges 53–66 kDa, depending on the conditions. Sulfation profiles were similar for all materials, with dominant CS-C (GlcA-GalNAc6S) units (55%), followed by 23–24% of CS-A (GlcA-GalNAc4S), a substantial amount (15–16%) of CS-D (GlcA2S-GalNAc6S) and less than 7% of other disulfated and unsulfated disaccharides.