Produção, otimização e caracterização de invertases e frutosiltransferases de aspergillus carbonarius para produção de alimentos

Abstract

Invertases are enzymes that catalyze the hydrolysis of sucrose in an equimolar mixture of D-glucose and D-fructose, commonly known as inverted sugar, which at high concentrations may exhibit significant transfructosylation activity. Frutosiltransferases have transfructosylation activity in high amounts of sucrose, hydrolyzing the þ- (1-2) bonds in sucrose and transferring the fructosyl radical to another sucrose molecule forming the fructooligosaccharides (FOS) and releasing glucose. These enzymes are widely used in food industries for the production of fructose syrup and fructooligosaccharide. Both enzymes can be produced by different microorganisms, however the fungi stand out, mostly the species of the genus Aspergillus. This work aimed to optimize the culture conditions for the production of invertase and fructosyltransferase by a new strain of Aspergillus carbonarius PC-4, the characterization of the culture conditions, as well as the biochemical characterization of the enzyme fructosyltransferase produced under submerged conditions. The optimization of invertase production was obtained using simplex lattice methodology, increasing the production by 1.67-fold (9.44 U/mL) when pineapple crown and yeast extract were used. The optimization of the fructosyltransferase production was obtained using CCRD. Physicochemical conditions to invertase production provided a yield of 18.67 U/mL of invertase, when incubated at 25°C, pH 5.5 and shaken at 180 rpm for 72 hours of cultivation. The fermentation parameters under these conditions were YP/S = 1184.82 U/g and PP = 4.41 U/h. The best cultivation conditions for fructosyltransferase production were obtained using Plackett & Burman design and Central Composite Rotational Design providing an increase of 1.77-fold (66.46 U/mL) when using pineapple crown and ammonium nitrate. The maximum production was obtained after 72 hours of cultivation at 28 °C, 180 rpm and pH 6. The biochemical properties of the fructosyltransferase showed that the best reaction conditions are pH 5 and 50 °C. The enzyme was stable at 40 °C, whose half-life (T1/2) was 1 hour. The use of the new strain of Aspergillus carbonarius PC-4 for the production of the enzymes was effective and could be used in the future for the production of fructose syrup and fructooligosaccharides.