Characterization of the ozone effect over an α-amylase from Bacillus licheniformis Martínez Gallegos, Juan Francisco Jurado Alameda, Encarnación Carrasquilla Carmona, José Luis Jiménez Pérez, José Luis Romero Pareja, Pablo María α-amylase Bacillus licheniformis Ozonation Starch Enzyme activity Amino acids oxidation Starch usually soils industrial process equipment, hence demanding specific washing procedures to ensure optimal products and reliable process performance. α-Amylases have been included in detergent formulations to hydrolyse starch making easier its elimination. Ozone is frequently used as disinfectant but could also help to remove the starchy soils improving the cleaning process. To study the effect of ozone on the enzyme, the ozonation of an α-amylase from Bacillus licheniformis at pH 7.5 and 25°C was carried out. Enzyme activity assays showed that the relative α-amylase activity after ozonation decreased with increasing ozone/enzyme molar ratio exponentially. On the other hand, the ozone concentration after the reaction was negligible as some enzymatic activity remained, being the ozone consumption fast due to the high reaction kinetics of aromatic and sulfur-containing amino acids residues of the enzyme. The UV and MALDI-TOF mass spectra confirmed the oxidation of these amino acids, while the peptide bonds were unaffected. Therefore the loss of the α-amylase activity observed would be caused by the oxidation of amino acids residues directly involved in the hydrolysis mechanism such as tyrosine and histidine and/or by denaturation of the enzyme upon amino acid residues oxidation. 2024-01-31T13:22:30Z 2024-01-31T13:22:30Z 2014 info:eu-repo/semantics/article Published version: Juan F. Martínez-Gallegos, Encarnación Jurado-Alameda, José L. Carrasquilla-Carmona, José L. Jiménez-Pérez, Pablo M. Romero-Pareja, Characterization of the ozone effect over an α-amylase from Bacillus licheniformis, Biochemical Engineering Journal, Volume 85, 2014, Pages 119-124. https://doi.org/10.1016/j.bej.2014.02.012 https://hdl.handle.net/10481/87837 10.1016/j.bej.2014.02.012 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess Attribution-NonCommercial-NoDerivatives 4.0 Internacional Elsevier