Short communication Enzymatic extraction of chondroitin sulfate from skate cartilage and concentration-desalting by ultrafiltration B. Lignot a, *, V. Lahogue b , P. Bourseau a a Laboratoire Polyme `res et Proce ´de ´s (L2P), Centre de Recherches, Universite ´ de Bretagne Sud, rue Saint Maude ´, F-56325 Lorient Cedex, France b ID.Mer, 2 rue Ba ˆtelie `re, F-56100 Lorient, France Received 6 January 2003; received in revised form 13 May 2003; accepted 26 May 2003 Abstract Skate cartilage is a fishery by-product, which contains chondroitin sulfate (CS), a glycosaminoglycan well known for its chondroprotective effect. Here described is a low-cost two-step process producing CS in non-denaturing conditions, consisting of an enzymatic extraction followed by tangential filtration to concentrate and purify CS. The performances of UF and MF membranes were compared in terms of flux and selectivity. The 0.1 mm-pore size membrane appeared to be the most efficient to separate CS from the other compounds. # 2003 Elsevier B.V. All rights reserved. Keywords: Glycosaminoglycan; Enzymatic hydrolysis; Desalting; Ultrafiltration; Marine by-products; Upgrading 1. Introduction Cartilaginous tissues are by-products which contain valuable molecules, glycosaminoglycans (GAGs) such as chondroitin sulfate (CS), which is exploited for its chondroprotective effect (Pipi- tone, 1991). Skate cartilage is reported to be exclusively composed of CS (Roy, 1998) covalently attached to a core protein, forming proteoglycans which are embedded in a network of collagen fibrils (Carney and Muir, 1988). Solubilization of CS requires to degrade both the collagen matrix and the core protein. The objective was to develop a low-cost techni- que of CS production easy to implement and preserving the CS structural integrity and biologi- cal properties. Crude papain was selected to perform the enzymatic extraction for its low-cost and high efficiency for digesting cartilaginous tissues (Scott, 1969). For CS purification, membrane processes were chosen as they are safe and provide, as a concentration mode, a low-energy consuming and mild alternative to evaporation process. They are also well suited to the industrial development of continuous processes and can be coupled with an enzymatic bioreactor. * Corresponding author. Tel.:  /33-2-9787-4533; fax:  /33-2- 9787-4588. E-mail address: brigitte.lignot@univ-ubs.fr (B. Lignot). Journal of Biotechnology 103 (2003) 281  /284 www.elsevier.com/locate/jbiotec 0168-1656/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0168-1656(03)00139-1