Naringin in naringenin conversion by Aspergillus niger

LEVIT, R.; VARGAS CORBALAN, M.; NAVARRO, A.; CERUTTI, G.; RUBIO, M.

Horco Molle. Tucumán

Jornada; XXX Jornadas Científicas de la Asociación de Biología de Tucumán; 2013

Asociación de Biología de Tucumán

Naringenin, which is important in the pharmaceutical industry, is obtained by enzymatic conversion of naringin. This process is expensive due to the import of naringinase (an enzymatic complex of α-L-ramnosidase (EC.3.2.1.40) and -D-glucosidase (EC.3.2.1.21). An alternative is to use Aspergillus niger, a producer of the enzyme, to obtain naringenin. The aims of this study were to determine the optimal conditions for naringenin conversion using A. niger and to study the reuse of the fungus to decrease conversion time. We studied the variations in 1) pH (3.5; 4.0; 5.0), temperature (20, 30 and 35 °C), naringin concentration (5, 10 and 20 g/l) and number of conidia (5 and 10 x 106 conidia/ml); 2) Reuse of the fungus for 120 h, changing the medium with naringin (5 g/l) every 24 h. Naringenin was determined by Habelt and Pittner, reducing sugars by Somogyi - Nelson and TLC to reveal the flavonoid. The maximum process efficiency (Ef: 53.88%) was at pH = 4; temperature: 30 °C; naringin: 5 g/l and 5 x 106 conidia/ml. In these conditions the fungus was reused for 120 h, with the same Ef: 54% and product yield (Yp/s = 0. 35 g/g). In conclusion, A. niger is effective to obtain naringenin in optimal conditions and fungal biomass with the same efficiency and faster conversion time than when it was reused.