Manteiga de bati (Ouratea parviflora): caracterização físicoquímica e utilização como substrato para produção de lipase por Aspergillus terreus em fermentação semi-sólida

Abstract

Lipases are enzymes belonging to a class of hydrolases that catalyze the breakdown of triacylglycerols, generating free fatty acids. The vegetable sources that are of greatest interest as a substrate for lipase production are those containing long chain triacylglycerols. In this context, the bati butter produced from Ouratea parviflora is an alternative for lipase production. The objective of this work was to evaluate the potential of bati butter (Ouratea parviflora) as a substrate for lipase production by Aspergillus terreus in semi-solid fermentation. Analysis of the composition of fatty acids and minerals, physicochemical characterization of bati butter and its use as an inducing substrate for lipase production at two different temperatures (25 ºC and 35 ºC) were carried out during 196 h of fermentation. The spore count was performed throughout the fermentation period. The crude enzymatic extract was evaluated against different pH, temperature and action of activating compounds and inhibitors. The butter had a high concentration of long chain fatty acids (C14 - C24). The presence of manganese (12.7 mg / g), calcium (7.7 mg / g), sodium (6.7 mg / g) and magnesium (5.4 mg / g) of iron (1.1mg / g) and copper (0.04mg / g) that exert a catalytic effect on lipid oxidation. Regarding the physical-chemical characteristics, a high acidity index (20.76 mg KOHg1) and peroxide (16.03 mEqkg-1) and low humidity (1.29%) were found. Regardless of the incubation temperature, the spore count of Aspergillus terreus was similar and increasing throughout the incubation period (196 h). However, the highest enzymatic activity was 212.6 U / g, produced in the 120 h period at 35 ° C, with specific activity of 144,5 U/mg. The crude enzymatic extract presented better relative activity at 37 ºC and pH 9. β-mercaptanol significantly increased the relative activity of the enzyme. The other compounds decreased the relative activity of the enzyme, especially the Sodium Docetil Sulphate (SDS) that inactivated the enzyme. In view of the results obtained it is stated that bati butter was an inducing substrate to produce lipase by semi-solid fermentation.