Enzymatic cleaning of inorganic ultrafiltration membranes u英文电子书.pdf

Journal of Membrane Science 216 (2003) 121–134 Enzymatic cleaning of inorganic ultrafiltration membranes used for whey protein fractionation M.A. Argüello a , S. Álvarezb , F.A. Riera a,∗, R. Álvarez a a ´ Department of Chemical Engineering and Environmental Technology, University of Oviedo, C/ Julián Claver ıa 8, 33 006 Oviedo, Spain b Department of Chemical and Nuclear Engineering, Polytechnical University of Valencia, C/ Camino de Vera s/n, 46022 Valencia, Spain Received 30 July 2002; received in revised form 30 January 2003; accepted 3 February 2003 Abstract The aim of this work was to study the cleaning of inorganic membranes fouled by whey protein solutions using proteolytic enzymes. Tami® 150 + 4T membranes (Tami Industries, S.A., 26110 Nyons, France) of 400 kg/mol molecular weight cut-off (MWCO) and a ZrO2 filtering layer were selected to carry out the tests and Maxatase® XL (Genencor International, 2333 CN Leiden, The Netherlands) and P3-Ultrasil® 62 (Henkel Ibérica, S.A., 08025 Barcelona, Spain) were investigated as cleaning agents. Cleaning efficiency was observed to be a function of the operating conditions. The operating conditions studied were the pH of the cleaning solution, the enzymatic agent concentration and cleaning time. Very high cleaning efficiencies (close to 100%) were achieved in short operating times (20 min). The proteolytic enzymes were observed to adsorb onto the inorganic membrane used. However, enzyme-cleaned membranes gave better results than chemically-cleaned ones when used for whey protein fractionation: higher permeate flux was obtained, while selectivity remained practically the same. No peptides were detected in the retentate and permeate streams resulting from