International Biodeterioration & Biodegradation 60 (2007) 219–225 Enzymatic pre-hydrolysis applied to the anaerobic treatment of efﬂuents from poultry slaughterhouses Alessandra Bormann Garcia Vallada˜o a , Denise Maria Guimara˜es Freire a , Magali Christe Cammarota b,Ã a Instituto de Quı´mica, Departamento de Bioquı´mica, Universidade Federal do Rio de Janeiro, Cidade Universita´ria, Centro de Tecnologia, Bl. A, Sl. 539, 21949-900, Rio de Janeiro, RJ, Brazil b Escola de Quı´mica, Departamento de Engenharia Bioquı´mica, Universidade Federal do Rio de Janeiro, Cidade Universita´ria, Centro de Tecnologia, Bl. E, Sl. 203, 21949-900, Rio de Janeiro, RJ, Brazil Available online 10 May 2007 Abstract A pool of hydrolases with 21.4 U g 1 lipase activity was produced through solid-state fermentation of the fungus Penicillium restrictum in waste from the Orbignya oleifera (babassu) oil processing industry. Enzymatic hydrolysis and anaerobic biodegradability tests were conducted on poultry slaughterhouse efﬂuents with varying oil and grease contents (150–1200 mg l 1 ) and solid enzymatic pool concentrations (0.1–1.0% w/v). Enhanced anaerobic treatment efﬁciency relative to raw efﬂuent was achieved when a 0.1% concentration of enzymatic pool was used in the pre-hydrolysis stage with 1200 mg oil and grease l 1 (chemical oxygen demand (COD) removal efﬁciency of 85% vs. 53% and biogas production of 175 ml vs. 37 ml after 4 d). r 2007 Elsevier Ltd. All rights reserved. Keywords: Anaerobic treatment; Hydrolases; Poultry slaughterhouse efﬂuent; Solid-state fermentation Scientiﬁc relevance of the paper Slaughterhouse wastewater contains high levels of fats and proteins that present low biodegradability. A large number of pre-treatment systems are employed to remove oil and grease to prevent a host of problems that may otherwise arise in the biological process, and reduce the efﬁciency of the treatment station. Problems caused by excessive oil and grease include a reduction in cell-aqueous phase transfer rates, sedimentation hindrance due to the development of ﬁlamentous microorganisms, development and ﬂotation of sludge with poor activity, clogging and the emergence of unpleasant odors. Thus, the application of a pre-treatment to hydrolyze and dissolve lipids may improve the biological degradation of fatty wastewaters, accelerat- ing the process and improving time efﬁciency. However thus far, only a few studies describing the degradation of fats and oils by alkaline/acid/enzymatic hydrolysis have been reported; the treatment of efﬂuents from several origins is a new and promising application for lipases. Among the organisms that produce the hydrolytic enzymes studied, the fungus Penicillium restrictum is a particularly promising one. The use of low-cost enzymatic preparations represents a vital development in the treatment of efﬂuents, since the use of high-cost commercial enzymatic prepara- tions would make the pre-treatment procedure economic- ally infeasible. In this context, it seems that the solid-state fermentation process will be a suitable technology once enzyme production can be performed in situ and industrial wastes can be employed as a source of nutrients for the fermentative process. When cultivated in low-cost solid medium composed of agro-industrial waste, P. restrictum produces a pool of hydrolases capable of degrading highly complex organic compounds. This degradation enables a considerable increase in organic matter removal efﬁciency to be realized, which produces a high-quality efﬂuent for subsequent biological treatment. Accordingly, there is ARTICLE IN PRESS www.elsevier.com/locate/ibiod 0964-8305/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.ibiod.2007.03.005 Ã Corresponding author. Fax: +55 21 2562 7567. E-mail address: christe@eq.ufrj.br (M.C. Cammarota).