English

Abstract

A total of 24 lipolytic yeasts were isolated from the spent olive derived from olive fruits of the Algerian variety Chemlal. One strain, G5, had the highest lipolytic activity (20 mm) on the tributyrin agar plate. The morphological, biochemical characterization and 18S rDNA gene analysis of the selected strain, confirms that it is Candida boidinii KF156789. The production of lipase and biomass were carried out in liquid and solid (spent olive) media. In submerged fermentation, it seemed that the production of enzyme reached its maximum 7.3 U/ml, whereas; the growth cells reached its maximum at 1.9 × 108 cell/ml. That can be explained by the assimilation of free fatty acids by this strain after degradation of olive oil by the enzyme. The production of lipase and biomass, in solid state fermentation, gave the maximum yield for cell growth (1.3 × 109 cell/ml), while lipolytic activity reached 4.8 U/g. The highest activity of the studied enzyme was at pH 7.0 and 37°C. The enzyme maintained more than 90% of its activity at pH 8.0-9.0 and 70% at temperature range of 4-40°C; it was concluded that the lipase from C. boidinii KF156789 has the potential to be an alkaline cold-adapted enzyme. Key words: Candida boidinii KF156789, higher lipase, alkaline cold-adapted lipase, chemlal spent olive, solid state fermentation.