Animal fleshing (ANFL), the major proteinaceous solid waste discharged from leather manufacturing industries was used as the substrate for the production of alkaline protease by Pseudomonas aeruginosa. The strain isolated from the tannery wastewater was selected for its ability to produce protease of activity in the range 1160-1175 U ml(-1). The selective removal of non-fibrillar proteins such as albumin and globulin from ANFL by the protease enzyme during the progress of hydrolysis was confirmed using scanning electron microscopy (SEM). The breakdown of ANFL was also confirmed from the amino acid release into the fermentation medium by P. aeruginosa using high performance liquid chromatography (HPLC). (c) 2007 Elsevier Ltd. All rights reserved.