The aim of this study was to characterize the properties of lactoferrin (LF) obtained in a process developed for its isolation from acid whey derived from the production of fresh curd cheese, using a unique technology of ion-exchange chromatography on CIM^® monolithic columns. The freeze-dried lactoferrin samples produced on the pilot plant (capacity 1 m³) were examined for the purity, iron-binding capacity, antibacterial activity, and pH- and temperature-stability. Apo-LF inhibited several tested strains (enterobacteria, Staphylococcus, Streptococcus salivarius) except clostridia, lactic acid bacteria, and bifidobacteria. Sample of LF intentionally saturated with Fe³⁺ lost its antibacterial activity, indicating the involvement of mechanisms based on depriving bacteria of an iron source. All samples, regardless of the iron-saturation level, exhibited stability in pH range 4.0 to 11.0. LF with higher iron content (A-value = 41.9%) showed better thermal stability. Heat treatment up to 72 °C/3 s did not reduce antimicrobial activity against E. coli O157: H7 tox-. Higher purity (above 91%), higher iron-binding capacity and higher inhibitory activity against E. coli O157: H7 tox- compared to some similar products from the market was observed. These results demonstrate a high potential of monolithic ion-exchange chromatography for industrial processing of acid whey as a source of LF that can be used in new products with high-added value. The upscaling of the process is ongoing on a demonstration plant (10–30 m³/day capacity).

The huge amounts of keratin-rich waste generated daily by various industries, slaughterhouses, and processing plants need to be properly managed. Most keratin degradation-related research focuses on keratin from bird feathers, but a vast minority focuses on keratin from sheep wool, which also presents a serious environmental problem. In this article, we describe the isolation, identification, and characterization of new keratinolytic microorganisms capable of sheep wool degradation from sheep wool and soil enriched with wool keratin. We isolated four bacterial species from the genus Bacillus (B. subtilis, B. altitudinis, B. mycoides, and B. wiedmannii), one streptomycete species Streptomyces coelicoflavus identified by whole genome sequencing, and a fungal species Aphanoascus reticulisporus. In some of the isolated microorganisms, we detected keratinolytic activity for the first time, and for most of them, the ability to degrade sheep wool has not been previously demonstrated. The keratinases of the new isolates are active in a wide range of temperatures (25–85 °C) and pH (6.0–10.0), so all isolates show great potential for further biotechnological use in industry and in various environmental and agricultural applications to reduce and recycle keratin-rich wastes such as sheep wool and waste woollen textiles.

In the Balkans, and probably elsewhere, whey from small dairies, especially acid whey, still poses an environmental challenge. Despite recent advances in whey processing technology, whey is still largely treated as waste or ends up in biogas plants. Due to its high lactic acid content, acid whey cannot be concentrated by conventional drying or used directly in food. However, it contains several valuable components that can be converted into products with high added value. For this purpose, a valorisation cascade was developed, part of which is the extraction of lactoferrin and lactoperoxidase from acid whey or sweet whey. The remaining whey was concentrated and used for the acidic precipitation of α-lactalbumin. In small-scale laboratory experiments, a purity of α-lactalbumin of 72.9 % and 24.8 % was achieved, when isolated from acid whey and sweet whey, respectively. The isolation procedure was then demonstrated on a pilot scale, using 70 L of acid whey, which yielded 220 g of wet isolate of α-lactalbumin with a purity of 78.1 % and a high lysine (11.1 %) and leucine (10.0 %) content. The remaining whey fraction could be used in various fermentation processes or other applications.