Lipase production by bacterial isolates from petroleum contaminated soil - DOI: 10.4025/actascitechnol.v32i1.7550

Abstract

Lipase production by bacterial isolates from petroleum contaminated soil. This paper aims to present alternatives to the production of lipolytic enzymes from microorganisms isolated from soil with a history of contact with oil from the region of Sergipe, by submerged fermentation using palm oil as inducer. The experiments were conduced in 250 mL Erlenmeyer flasks in a shaker (170 rpm), containing 125 mL (%, w v^-1) of KH₂PO₄, MgSO₄.7H₂O, NaNO₃, yeast extract, peptone and starch. The pH was 5.0 and 7.0; incubation temperature was 30 and 37°C, respectively; fermentation time was 24, 48, 72, 96h, 120 and 144h; and the inducer concentration was 3 and 4%, added after 72h of fermentation. The determination of lipolytic activity was examined at 37°C, in a shaker in thermostatic bath with rotation of 82 rpm, using gum arabic 7% (w v^-1), olive oil and water. The reactions were conducted for 10 min with agitation and later stopped by the addition of an acetone:ethanol:water solution, where released fatty acids were titrated with a solution of KOH (0.04 N), using phenolphthalein as an indicator. The maximum activity was determined as 4369.75 U mL^-1 pH 7.0 and a temperature of 37°C, with the percentage of the inducer oil palm to 4%.