Wool‐waste valorization: production of protein hydrolysate with high antioxidative potential by fermentation with a new keratinolytic bacterium, B acillus pumilus A1

Aims Wool, a recalcitrant waste mainly composed of keratin, constituted a serious problem for the environment and was not effectively valorized. This study reported the optimization of wool‐waste biodegradation by a new keratinolytic bacterium B acillus pumilus A1. The in vitro digestibility and the antioxidant potential of wool protein hydrolysate ( WPH ) were also investigated. Methods and Results The antioxidant potential of WPH was evaluated using in vitro antioxidant assays, such as 1,1‐diphenyl‐2‐picrylhydrazyl ( DPPH ) radical‐scavenging activity, reducing power and metal (Fe 2+ ) chelating activity. Cultivation on 50 g l −1 of wool for 2 days, at 45°C and at initial pH of 10, resulted in maximum production of amino acids and peptides (39·7 g l −1 ). WPH presented a very high in vitro digestibility (97%) as compared with that of the untreated wool (3%). Conclusions The keratin present into the wool‐waste was completely solubilized. Interestingly, WPH presented an important DPPH radical‐scavenging activity with an IC 50 value of 0·14 ± 0·01 mg ml −1 . Significance and Impact of Study WPH would be a very useful source of protein and antioxidants in animals’ diets.