Carbon Source Effects on YR-1 Strain 161 Applied Biochemistry and Biotechnology Vol. 113–116, 2004 Copyright © 2004 by Humana Press Inc. All rights of any nature whatsoever reserved. 0273-2289/04/113/0161–0171/$25.00 161 *Author to whom all correspondence and reprint requests should be addressed. Effects of Carbon Source on Expression of Alcohol Oxidase Activity and on Morphologic Pattern of YR-1 Strain, a Filamentous Fungus Isolated from Petroleum-Contaminated Soils CARMEN RODRÍGUEZ ROBELO, VANESA ZAZUETA NOVOA, AND ROBERTO ZAZUETA-SANDOVAL * Instituto de Investigación en Biología Experimental, Facultad de Química, Universidad de Guanajuato, Noria Alta s/n, Apartado Postal 187, Guanajuato, Gto. 36000, México, E-mail: zazueta@quijote.ugto.mx Abstract Soluble alcohol oxidase (AO) activity was detected in the supernatant frac- tion of a high-speed centrifugation procedure after ballistic cellular homo- genization to break the mycelium from a filamentous fungus strain named YR-1, isolated from petroleum-contaminated soils. AO activity from aerobi- cally grown mycelium was detected in growth media containing different carbon sources, including alcohols and hydrocarbons but not in glucose. In previous work, zymogram analysis conducted with crude extracts from aero- bic mycelium of YR-1 strain indicated the existence of two AO enzymes origi- nally named AO-1 and AO-2. In the present study, we were able to separate the AO-1 band into two bands depending on culture conditions, carbon source, and polyacrylamide gel electrophoresis (PAGE) separation condi- tions; the enzyme activity pattern in zymograms from cell-free extracts exhib- ited three different bands after native PAGE. New nomenclature was used for upper bands AO-1 and AO-2 and lower band AO-3, respectively. The expres- sion of AO activity was studied in the absence of glucose in the culture media and in the presence of hydrocarbons or petroleum as sole carbon source, suggesting that AO expression could be subjected to two regulatory possibili- ties: carbon catabolite regulation by glucose and induction by hydrocarbons. The possibility of catabolic inhibition of AO by glucose in the active enzyme was also tested, and the results confirm that this kind of regulatory mecha- nism is not present in AO activity.