PHYSICOCHEMICAL FACTORS AFFECTING THE PRODUCTION OF TANASA BY Aspergillus niger

PACHECO, MARIANA; STIVALA, MARÍA GILDA; RUBIO, MARÍA CRISTINA

Tafí del Valle - Tucumán

Jornada; XXXV Jornadas Científicas de la Asociación de Biología de Tucumán; 2018

Asociación de Biología de Tucumán

Tanasa (Tanin-acyl-hydrolase, EC 3.1.1-20) hydrolyzes links ester of hydrolysable tannins and gallic acid esters. It is used in the food, pharmaceutical and chemical industry. However, its lack of in situ availability in the field makes its importation extremely expensive. The objective of this work was to study the physicochemical factors that affect the production of the enzyme. A strain of Aspergillus niger from the Biotechnology Institute was used. The production medium contains, g/L: NaNO3, 3; MgSO4.7H2O, 0.5; KH2PO4, 1; KCl, 0.5. We studied: 1) concentration of tannic acid (5-10g/L); (2) pH (4, 4.5 and 5); 3) temperature (25, 30, and 35°C); 4) shaking speed (150, 200 and 250rpm); 5) incubation time (12, 24, 36, 48, 72h). The results showd that the maximum units of enzyme (324U/mL) were found at 36h of incubation when using 10g/L of tannic acid and 250rpm. At pH 5, the enzyme units decreased by 64.5% and 12% less at pH 4.0, with respect to pH 4.5. Temperatures higher than 30°C produced a decrease in enzyme production of 49%, reaching a maximum of 30°C. In conclusion, the maximum performance in enzymes with respect to the development of cell mass was YU/X=253U/g and productivity, Pdv=9U/mL h at 36h of incubation, at pH 4.5 and 250rpm with 10g/L of tannic acid, with respect to 5g/L acid (YU/X=182U/g and Pdv=7U/h mL). The conditions of production obtained can be used in future studies using agro-industrial waste containing tannins, in order to reduce the cost of the substrate and of the total process.