Karel Kolomaznik

Abstract:

Natural polymers as products of animal and plant organisms play an irreplaceable role in the life of human society. The main natural polymer raw materials are cellulose, starch, chitin and proteins, which are mainly processed by the food, textile, leather, wood-processing and paper industries. Industrial processing of natural polymers, besides valuable final products, also generates large quantities of by-products, i.e. waste of different composition and quality. Our contribution deals particularly with protein waste (predominantly collagen and keratin) generated by the leather, textile and meat industries. Leather industry is one of major producers of solid protein waste, which often contains also potentially hazardous chemicals. In spite of numerous technological solutions described in the literature for collagen-based wastes, huge amounts of this waste are still left unutilized [1] and its sustainable valorization remains challenging not only from the technological point of view, but also from the viewpoint of commercial application of the products. Common utilization of the products as animal feed or fertilizers may not satisfy the increasing market demand for advanced products, or can be limited due to hygienic regulations related to certain animal by-products; therefore, it is necessary to shift research efforts in protein waste processing towards protein-based products with higher utility value [2] and potential applications in other industries. This also applies to waste keratin (wool, hair, feather...), the unique structure of which makes it difficult to process and to find a feasible and efficient technology of its treatment [3].
We present several successful technological procedures for the processing of protein-based waste generated mainly by the leather, textile and meat industries, from laboratory experiments to scale-up from the laboratory to pilot scale and industrial production using mathematical-physical models verified by laboratory measurements. The procedures specifically include: 1) Processing of potentially hazardous chrome shavings from tanneries; 2) Technology of complete processing of green fleshings, another problematic primary waste from tanneries, into biodiesel and protein hydrolysate; 3) Hybrid technology applied to manipulation waste from footwear production; 4) Processing of protein waste generated during production of collagen casings for the meat industry; 5) Innovative method for the treatment of resistant keratin-based waste from textile and food industries.
The processing technologies are based on hydrolysis of the feedstock carried out in an acidic or alkaline environment. Reactions in an alkaline environment are usually catalyzed by proteolytic enzymes. We also present most recent progress in selected technologies, applications of hydrolysis products in agriculture including eco-farming, and discuss their potential as auxiliary agents in the construction, plastic and rubber industries.

[1] Umme Habiba Bodrun Naher, MD. Rashidul Islam, MD. Abu Sayid Mia, MD. Farhad Ali, IJSETR 7 (2018) 837-841.
[2] M.B.A. Kumar, Y. Gao, W. Shen et al., Front. Chem. Sci. Eng. 9 (2015), 295-307.
[3] C.R. Holkar, S.S. Jain, A.J. Jadhav, D.V. Pinjari, Process. Saf. Environ. 115 (2018) 85-98.