Production and concentration of keratinases and application of fermentation residual in removing hexavalent chromium

• Published in: Bioprocess and biosystems engineering 2024-12, Vol.47 (12), p.2091-2099
• Main Authors: Warken, Andressa Janaína, Kubeneck, Simone, Camargo, Aline Frumi, Longo, Vitória Dassoler, Romani, Larissa Capeletti, Klein, Gabriel Henrique, Alves, Sérgio L., Shah, Maulin P., Treichel, Helen
• Format: Article
• Language: English
• Subjects: Acetone; Ammonium; Ammonium sulfate; Aspergillus niger; bioprocessing; Bioreactors; Biotechnology; Chemistry; Chemistry and Materials Science; Chromium; Environmental Engineering/Biotechnology; Enzymes; Fermentation; Food Science; Hair; Hexavalent chromium; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Keratinase; potassium; Potassium dichromate; Purification; Research Paper; Sodium chloride; solvents; submerged fermentation; Substrates; Swine
• ISSN: 1615-7591; 1615-7605; 1615-7605
• DOI: 10.1007/s00449-024-03087-0

The production of keratinases was evaluated in submerged fermentation with Aspergillus niger and by pigs’ swine hair in a batch bioreactor. Experimental planning was performed to assess the interaction between different variables. The enzyme extract produced was characterized at various pH and temperatures and subjected to enzyme concentration using a biphasic aqueous system and salt/solvent precipitation techniques. In addition, the substrate’s potential in reducing hexavalent chromium from synthetic potassium dichromate effluent with an initial concentration of 20 mg L −1 of chromium was evaluated. The resulting enzyme extract showed 89 ± 2 U mL −1 of keratinase. The enzyme concentration resulted in a purification factor of 1.3, while sodium chloride/acetone and ammonium sulfate/acetone resulted in a purification factor of 1.9 and 1.4, respectively. Still using the residual substrate of swine hair from the fermentation, a 94% reduction of hexavalent chromium concentration occurred after 9 h of reaction. Thus, the study proved relevant for producing keratinases, with further environmental applicability and the possibility of concentrating the extract via low-cost processes.