Analyzing the Mechanism and Effect of Acid Protease in Wet blue Bating Process for Leather Production

In recent years, in order to reduce the pollution produced in beam-house and tanning sections, more and more tanneries purchase wet blue from other factories in other regions directly used as raw materials for finished leather production thereby those polluted preliminary steps can be eliminated. Therefore, the wet blue bating process is an essential step to minimize the differences of wet blue which are purchased from different regions. In this study, the properties of different acid protease are analyzed for selecting suitable protease used for wet blue bating. The analysis of chromium tolerance of different acid proteases reveals that, L1 and L4 produced from Aspergillus have higher chromium resistance than that of produced from Bacillus. The effect of L1 and L4 on wet blue and collagen shows that the L1 has more excellent performance, in which the molecular weight of functional protein is 48 KD. By SEM and MCT analysis, L1 can successfully disperse the collagen fibers of wet blue. Furthermore, the biodegradation rates of collagen and elastin were 0.006‰ and 0.5‰, respectively. It indicates that the acid protease mainly degraded elastin but not collagen in bating process thereby ensuring production safety. This paper provides the importance references for the application and the basis for the development of mechanism of acid protease in bating process.