Amylase production by Aspergillus niger in submerged cultivation on two wastes from food industries Mabel Salas Herna ´ndez a , Marilu ´ Rodrı ´guez Rodrı ´guez a , Nelson Pe ´rez Guerra b, * , Renato Pe ´rezRose ´s c a Departamento de Fundamentos Quı ´micos y Biolo ´ gicos, Facultad de Ingenierı ´a Quı ´mica, Universidad de Oriente Sede ‘‘Julio A. Mella’’, 90900 Santiago de Cuba, Cuba b Departamento de Bioquı ´mica, Gene `tica e Inmunologı ´a, Facultad de Ciencias de Ourense, Universidad de Vigo, As Lagoas, s/n. CP 32004 Ourense, Spain c Facultad de Farmacia, Universidad de Oriente, Sede Central, 90500 Santiago de Cuba, Cuba Received 6 December 2004; accepted 14 January 2005 Available online 5 March 2005 Abstract Synthesisofamylaseandproteaseby Aspergillus niger strainUO-1wasfollowedinmediapreparedwithbrewery(BW)andmeat (MPW)wastewaterssupplementedwithdifferentstarchconcentrations.Thehighestamylase(70.29and60.12EU/mL)andprotease (6.11and6.03EU/mL)productionwere,respectively,obtainedintheBWandMPWmediasupplementedwith40gofstarch/Lof medium after 88h of fermentation. In addition, the initial chemical oxygen demand (COD) in both wastes was reduced by more than 92%. HighamylaseandproteaseactivitieswerefoundintheBWmediumsupplementedwithcasaminoacids,peptoneoryeastextract, butammoniumnitrateandsodiumnitratewerealsogoodnitrogensourcesforamylaseproduction.Thestabilitiesofamylaseand proteasewerehigherat50 °CandpH4.95andat53.4 °CandpH3.87,respectively,buttheywerehighlysensitiveattemperaturesof 70 °C or higher. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Aspergillus; Amylase; Protease; Meat processing wastes; Brewery wastes; Chemical oxygen demand (COD) 1. Introduction Themeatandbreweryindustriesproducelargequan- tities of wastewaters with a high chemical oxygen de- mand (COD) and biochemical oxygen demand (BOD). The untreated effluents of the ‘‘Hatuey’’ brewery with a BOD (500–2600mg/L), COD (780–3500mg/L) and untreated wastes from the meat processing plant with a BOD (600–3000mg/L) and COD (800–4000mg/L) represent a serious environmental problem in Santiago deCuba.Therefore,itisnecessarytodevelopcleantech- nologies for treating these effluents. The possibility of depuration of other wastes from food industry, by using them as substrates for various bioproductions of potential economic interest has been reported before (Guerra & Pastrana, 2003; Murado et al., 1993; Roukas, 1999). Mussel processing wastes weresatisfactorilyusedforproducingsinglecellprotein andahighlystableamylolyticpreparationfromdifferent Aspergillus strains(Muradoetal.,1993). The biological treatment of these wastes was found to be an efficient way for reducing their initial COD by more than 90% (Murado et al., 1993). 0260-8774/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jfoodeng.2005.01.009 * Correspondingauthor.Tel.:+3488387062/626970159;fax:+34 88 387 001. E-mail address: nelsonpg@uvigo.es (N.P. Guerra). www.elsevier.com/locate/jfoodeng Journal of Food Engineering 73 (2006) 93–100