Abstract

The aim of this study was to isolate and select lipase-producing microorganisms originated from different substrates, as well as to optimize the production of microbial lipase by submerged fermentation under different nutrient conditions. Of the 40 microorganisms isolated, 39 showed a halo around the colonies and 4 were selected (Burkholderia, Bacillus sp., Penicillium lanosum and Corynebac glutamyl), where strains showing lipolytic halo Radius (R) / colony radius (r) ratio greater than 2.0 were selected. The results of submerged fermentation expressed as enzymatic activity revealed that the genera of microorganisms significantly influenced the enzymatic reaction, and lipase obtained from Burkholderia cepacia was the most promising, with activity of 0.0058 U.mL^-1. It was also observed in the optimization step of lipase production that the sodium nitrate content (NaNO₃) had a positive effect on enzyme production, and its increase was indicative of higher enzymatic activity. The addition of sources of organic nitrogen (corn steep liquor, p = 0.2398), carbon (soybean oil, p = 0.3379), magnesium MgSO₄.7H₂O (p = 0.4189) and potassium KH₂PO₄ (p = 0.8562) had no significant effects on the lipase production and could result in decreased production of extracellular lipases.

Key words: Burkholderia cepacia, hydrolytic enzymes, residue, submerged fermentation.