High-level lipase production by <i>Aspergillus candidus</i> URM 5611 under solid state fermentation (SSF) using waste from <i>Siagrus coronata</i> (Martius) Becari

Abstract

The current study evaluated lipase production by Aspergillus candidus URM 5611 through solid state fermentation (SSF) by using almond bran licuri as a new substrate. The microorganism produced high levels of the enzyme (395.105 U gds^-1), thus surpassing those previously reported in the literature. The variable moisture content, the inductor concentration, temperature and pH were analyzed. The best production conditions were initial moisture content of 75%, 0% of inductor, at 25°C, pH 5.5, in 10.0 g of substrate. The variables initial moisture and inductor contents showed significant effects on lipase production by increasing enzyme activity in about 200% when compared with the initial screening (197.44 U gds^-1). Optimum lipase activity was obtained at pH 2.5 at an optimum temperature of 65°C. The lipase was stable from pH 2.5 to 9.0 and at temperatures between 30 to 65°C. Results from the study are promising for the economic use and value addition from these important agro residues, which are abundantly available in Brazil. This is the first report on lipase production by A. candidus URM 5611 reaching a much higher yield of enzyme under SSF with almond bran licuri used as substrate.
 
Key words: Aspergillus candidus URM 5611, solid state fermentation (SSF), licuri waste, lipase characterization.