Produção e purificação de frutosiltransferase por Aspergillus Flavus utilizando borra de café (Coffea sp.) através da fermentação em estado sólido

Abstract

Frutosiltransferase (FTase) is an enzyme that catalyzes the breakdown of the glycosidic bonds of the sucrose molecule by transferring the fructosyl group to another molecule, which can be sucrose or fructooligosaccharides (FOS), resulting in the release of glucose. FOS is a conventional prebiotic that has a low calorimetric value and promotes the selective stimulation of the intestinal microbial growth, especially of bifidobacteria and lactobacilli, reducing the risks of cardiovascular disease, colon cancer and obesity. However to obtain the use of enzymatic processes is more expensive due to the high cost of production. However, these factors can be overcome with the use of microorganisms and agroindustrial residues as a culture medium for a solid fermentation, making the procedure more economical and feasible. The objective of this work was the production of the enzyme fructosyltransferase in solid fermentation using coffee grounds from Aspergillus flavus, where it was possible to verify that 72h of growth presented higher production of the enzyme with specific activity of 31.5 U / mg in the following conditions, 60% moisture, spore concentration 106 spores / mL at 30 ° C for 120 hours. The crude extract containing the enzyme was subjected to a precipitation selection between ketone, ammonium sulfate and ethanol, where the highest enzymatic activity was given using the precipitation with acetone 161.85 U / mL and relatively high purification factor of 10.70. Subsequently the sample was purified by DEAE SEPHADEX A50 and SUPERDEX AKTA ion exchange chromatography systems on the DEAE-sephadex system haithap and superdex 75 columns being carried out in sequence. The purified enzyme had 57 kDa molecular weight in Superdex G-75. Regarding the characterization, it presented optimum temperature of 60ºC respectively, obtaining thermo stability at 50ºC. The purification results showed a fraction with enzymatic activity for pure fructosyltransferase in which it obtained a purification factor of 86.16. When observed its enzymatic synthesis it was verified that the enzyme can produce fructooligosaccharides, being kestose and nystose. The results obtained in the present study show the promising potential of the fructosyltransferase produced by Aspergillus flavus and its use for the production of fructooligosaccharides.