Abstract
Traditionally, universally used pelt bating technologies rely on the application of trypsin, neutral and alkaline microbial proteases but suffer from complicated operation, limited bating efficiency and unsatisfactory leather performance. Therefore, devising a new pelt bating approach to achieve high bating efficiency and excellent leather performance has always been wished for by the leather industry. To pursue this goal, years of persistent research work enabled us to develop a novel approach for pelt bating by means of acidic proteases in pickling process. Initially, basic enzymatic characteristics and bating effectiveness of several typical acidic proteases in pelt pickling medium were investigated; then, the bating effectiveness through the quantitative characterization of protease activity of the optimal acidic protease was compared with that of the conventional bating enzyme. The results indicated that all of the selected acidic proteases had good salt-tolerance and exhibited optimum activity at pH 3.0–4.0. The novel pickling-bating method based on microbial origin acidic protease L80A led to an outstanding performance on pelt bating at the dosage of 150 U/mL of collagenolytic activity. The bating effectiveness of acidic protease L80A was comparable to and even better than that of trypsin BEM due to its moderate proteolytic ability. Moreover, the deep and even penetration of acidic protease in the pelt permitted it to produce soft, organoleptically stable and overall better quality crust leather than that of the conventional trypsin bating method. Additionally, pelt bating was performed along with the pickling process without extra inactivation and washing operation, making the bating operation more efficient, economical, and environment friendly. Results had made us to conclude that this cutting-edge acidic proteases based pickling-bating method could be the first step/ way forward to replace the decades-old traditional pelt bating technology.
Highlights
Bating is one of the most important procedures executed on delimed pelts with the help of enzyme preparations for removing unwanted components and ancillary opening up protein structures [1,2,3,4,5]
The relative collagenolytic activity of these proteases remained 90% even the concentration of NaCl was augmented to 120 g/L, indicating their adaptability for the pickling-bating conditions as the conventional pickling operation almost always contains 60–100 g/L of NaCl
On the way forward to select an appropriate picklingbating enzyme, we had compared the bating effectiveness of different typical acidic proteases with the same dosage of caseinolytic and collagenolytic activity, respectively. These results suggested that the bating effectiveness of acidic proteases on pickling pelts mainly depends on the relative activity, namely the purity of active proteins, especially the collagenolytic activity, i.e. proteases with high collagenolytic activity and purity can significantly improve the softness of the crust leather
Summary
Bating is one of the most important procedures executed on delimed pelts with the help of enzyme preparations for removing unwanted components and ancillary opening up protein structures [1,2,3,4,5]. In the conventional bating process, pelt bating is carried out in a deliming solution with the help of enzyme preparations at 30–37 °C and pH 7.0–8.5 [8, 9]. Pickling is a process in which delimed pelt (pH is in the range of 7.0–8.5) is acidified in a salt solution with the application of formic acid and sulfuric acid to adjust the end pH of the float at 2.8–3.0 and modify the reactivity of the carboxyl groups in collagen fibers [2, 10]. The conventional bating-washing pickling-chrome tanning process is very complicated, ends up with limited production capacity and a lot of pollution
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
