TY - JOUR
T1 - Characterization of the ozone effect over an α-amylase from Bacillus licheniformis
AU - Martínez-Gallegos, Juan F.
AU - Jurado-Alameda, Encarnación
AU - Carrasquilla-Carmona, José L.
AU - Jiménez-Pérez, José L.
AU - Romero-Pareja, Pablo M.
N1 - Funding Information:
This work was financed by research projects P07-TEP-02603 , from the Council for Innovation, Science and Enterprise of the Andalusian Regional Government , and CTM2010-16770 , from the Ministry of Science and Innovation of Spain .
PY - 2014/4/15
Y1 - 2014/4/15
N2 - 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.
AB - 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.
KW - Amino acids oxidation
KW - Bacillus licheniformis
KW - Enzyme activity
KW - Ozonation
KW - Starch
KW - α-Amylase
UR - http://www.scopus.com/inward/record.url?scp=84896780121&partnerID=8YFLogxK
U2 - 10.1016/j.bej.2014.02.012
DO - 10.1016/j.bej.2014.02.012
M3 - Artículo
SN - 1369-703X
VL - 85
SP - 119
EP - 124
JO - Biochemical Engineering Journal
JF - Biochemical Engineering Journal
ER -