XXXIII IULTCS Congress November, 24 th – 27 th , 2015 Novo Hamburgo/Brazil 1 188 Extraction of Bovine Hair Keratin From Unhairing Waste of Hides Franck Souza 1 , Michael Meyer 2 , Hauke Wulf 2 , Enno Klüver 2 , Míriam Cooper¹, Mariliz Gutterres 1 1 LACOURO, Federal University of Rio Grande do Sul, Rua Engenheiro Luiz Englert, s/nº - Prédio 12204, 90040-040 Porto Alegre – Brazil +55(51) 3308 3954 – mariliz@enq.ufrgs.br 2 Research Institute of Leather and Plastic Sheeting - FILK, Meißner Ring 1-5, D- 09599 Freiberg – Germany +49 (0)3731 3660 – mailbox@filkfreiberg.de Abstract The high organic load of unhairing wastewater from leather processing is mainly caused by dissolved hair. However, this keratin-rich material can be recovered if it is not degraded completely in the course of the liming step. This study features the hydrolysis of keratin from bovine hair before and after treatment in seven different chemical solutions. The raw material was obtained by a hair-saving unhairing process, recovered from waste and from natural trimmed hairs respectively. We show here that it is possible to recover proteins with molecular weights around 20 kD are using this hair waste. Applying hydrogen peroxide during hydrolysis procedure, approximately 75 % of the protein can be recovered and up to 90 % yield can be reached when sodium sulfide is used in a reductive pathway. Keywords: protein hydrolysis, waste recovery, sulfitolysis, cystine, lanthionine. 1 – Introduction During hide processing in tanneries hair is removed at the liming stage. Through this operation, which is usually performed in an aqueous medium, calcium hydroxide is added to promote the rise of the pH leading to the swelling of the dermis; furthermore chemicals are employed with the purpose to remove the hair. In the course of liming this material is dissolved and consequently increases the biochemical oxygen demand (BOD) and chemical oxygen demand (COD) levels of the effluent. Parts of the organic load are only slowly degradable and contribute to sludge formation during wastewater treatment (Morera et al., 2008). Unhairing processes can be divided in two main groups: processes that destroy the hair fibers (hair- burning processes) and processes with preservation of the hair fibers (hair-saving processes). Hair- burning unhairing is state of the art since more than hundred years, which utilizes sodium sulfide or sodium hydrosulfide and lime (Valeika et al., 2009). However, this step is also the most polluting stage of this industry (Davies, 1997; Lambert et al., 2006). The extensive use of hazardous sulfide can not only lead to harmful consequences for workers and environment, but it also needs to be completely removed from the effluent of the wastewater treatment plants (Skrajny et al., 1996; Zhi-Hua et al., 2009 ). Hair-saving unhairing methods as an alternative can be based on several technologies and chemicals such as microbial enzymes (Dettmer et al., 2013), oxidative processes (Morera et al., 2008), oxidative processes combined with enzymes (Andrioli and Gutterres, 2014), commercial enzymes in addition to small quantities of sodium sulfide (Souza and Gutterres) and unhairing with amines (Marsal et al., 1999), to name a few among others. Hair-saving processes are followed by a filtration step to remove the hair from the wastewater, in order to pour less organic matter in the wastewater as well as less hazardous chemicals (or the absence of them in some cases as the unhairing with