ABSTRACT Microorganisms capable of simultaneously producing lipases and biosurfactants might be very useful for the bioremediation and industrial processes. In this study the production of lipases and biosurfactants from bacteria isolated from soil experimentally contaminated by residual vegetable oil was analyzed. All isolates tested namely Burkholderia (six isolates), Bacillus (three isolates) and Ralstonia (two isolates) produced lipases in the agar medium with rhodamine B and olive oil, and quantitative analysis of lipolytic activity showed variations at different temperatures, pH and substrates (olive oil, diesel oil). Most isolates showed the highest lipolytic activity at pH 7.0, especially at 50 oC, while at 37 °C many isolates showed similar lipolytic activity at pH 7.0 and 8.0. In relation to biosurfactant production, all isolates were capable of dispersing diesel oil and expressed hemolytic activity on blood agar plates, while 50% of isolates were able to emulsify diesel oil. The Burkholderia isolates showed stronger emulsification of diesel oil in the presence of residual vegetable oil in culture medium, while Bacillus and Ralstonia showed higher emulsification ability when the culture was supplemented with diesel oil. The highest dispersion value, emulsification index and the highest total lipolytic activity (1789.79 U/l in the presence of olive oil, pH 8.0, 37 °C) were observed for the Burkholderia sp. AL06, indicating its potential for application in the industrial and biotechnological processes.
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