Abstrakt

Naringinase production by Aspergillus niger in the fermentation of different carbon and nitrogen sources

Robson Alessandro Mattos Machado, Jo�������£o Batista Buzato, Cec�������­lia Duarte Dias, Maria Antonia Pedrine Colabone Celligoi

Citrus fruit and frozen concentrated orange juice production is of great commercial importance for Brazil. Excessive bitterness is the main depreciator of juice value on themarket.Naringinase, an enzymatic complex that degrades naringin, has potential application for debittering. This study investigated naringinase production by Aspergillus niger through sucrose, naringin, molasses and sugarcane juice, supplemented with peptone and sodiumnitrate. Naringin, when used in the culture mediumas inducer, was added in a single or fractioned doses. The base culture medium contained (g/L): 1.0 KH2PO4; 0.5KCl; 0.5MgSO4.7H2Oand 0.1 FeCl3. The fermentationswere carried out in 500mLErlenmeyer flaskswith 100mLculturemedium, at initial pH4.5, inoculumwith 106spores/mL, 28°C and 180rpm. The molasseswasmore efficientwhen used at lowconcentrations for naringinase production, while at high concentrations it only increased invertase production. The greatest naringinase value of 178.6mUI/mLwas attained with a combination of molasses (3g/L), peptone (10g/L) and naringin (0.5g/L). The fractioned addition of naringin as inducer did not improve production and therefore it is not recommended. Aspergillus niger showed promising potential as a biotechnological tool for naringinase production using a low-cost substrate.