Factors affecting mass transfer of protease in pelt during enzymatic bating process

Abstract

Bating pelt with protease is an important process, which removes unwanted non-collagenous proteins from the pelt and moderately disperse hide collagen network. However, the grain surface, may be excessively hydrolyzed during bating due to the longer retention time of protease in the grain than in the middle layer caused by the low mass transfer rate of protease in pelt. Here, the effects of protease dosage, common auxiliaries and molecular weight of protease on protease transfer during bating were investigated so that we can find the key points to avoid excessive collagen damage, particularly in the grain. Observably, increasing protease dosage led to faster protease transfer and softer leather, but along with more considerable grain damage. Using penetrating agent JFC (fatty alcohol-polyoxyethylene ether) and ammonium sulfate enhanced protease transfer and simultaneously alleviated collagen damage due to the decrease in interfacial tension and electrostatic attraction between protease and pelt, respectively. Additionally, proteases with lower molecular weight transferred faster in pelt, which suggests that a potential strategy to solve the conflict between the mass transfer and the reaction of protease in pelt might be to produce/employ smaller bating proteases.

A faster and more effective chrome tanning process assisted by microwave

“…It is necessary and important for chemicals to penetrate into the leather and distribute evenly; in this way, the relevant procedures will be carried out favorably and leather will have better performances. 23 In normal chrome tanning process, pickled pelt is tanned under low pH to allow the chrome tanning agent to penetrate at rst, and then alkali is added to increase the pH of the tanning system to enhance the combination between collagen and chromium. Previous studies have demonstrated that stronger tanning effect was obtained during hide powder chrome tanning process.…”

Life Cycle Assessment for Chrome Tanning, Chrome-Free Metal Tanning, and Metal-Free Tanning Systems

“…The functional unit of three tanning systems in the present assessment is defined as processing 1000 kg of pickled pelt because the pickled pelt is not only a raw material for tanning but also an important intermediate product that can be traded in the leather industry. Modern leather processing, as shown in Figure , involves raw hide preservation, beamhouse (removal of noncollagen components from hides and dispersion of collagen fibers to obtain the pickled cow hide), − tanning (conversion of a raw hide into durable leather by cross-linking collagen fibers with a tanning agent), , post-tanning (endowing leather with satisfactory physical and organoleptic properties using retanning agents, dyestuffs, and fatliquors), , finishing (giving leather artistic beauty and special functions such as waterproof and dustproof), packaging, and transportation. The main differences in the inputs and the outputs of various tanning systems are from tanning and post-tanning stages rather than the other stages (see Figure S3).…”

Interaction between retanning agents and wet white tanned by a novel bimetal complex tanning agent

“…In addition, the samples retanned with ME were cut along the vertical direction, and the vertical sections were directly observed by a stereo microscope (SZX12, Olympus, Japan) to locate ME in leather. The fluorescence and stereo micrographs were processed by Image J software to calculate the relative content and the penetration rate of fluorescent retanning agent in leather [22].…”