The operational conditions of β-galactosidase encapsulated in pectin-alginate hydrogel were investigated as well as its catalytic activity in the hydrolysis of lactose from whey and whole milk. β-Galactosidase encapsulated in pectin-alginate hydrogel showed the best results to yields and diffusional effect and pH range. Thermostability showed considerable income gain for half-life (1.7-fold), activation energy of denaturation (31.6-fold), activation of denaturation (217.3-fold at 40 ºC; 266.8-fold at 50 ºC; 345.6-fold at 60 ºC), and entropy of activation of denaturation (-42.0 J mol 1 K-1). Reusability of encapsulated β-galactosidase was observed in 8-cycles for the milk whey lactose hydrolysis (51.9%) and 7-cycles for whole milk (55.6%), and the lactose hydrolysis was observed in 13% in milk whey and 10.3% in whole milk after 10 cycles. These results revealed an industrial application potential of β-galactosidase encapsulated in pectin-alginate hydrogel for lactose hydrolysis of milk whey and whole milk processes.

Abstract Fructooligosaccharides (FOS) are mainly produced by microbial fructosyltransferases (FTase, E.C.2.4.1.9), and Aspergillus oryzae IPT-301 has shown high fructosyl transferring and low hydrolytic activities, which leads to high FOS production yields, but the main operating parameters for its best performance have been scarcely studied. Thus, this work aimed to evaluate the cellular growth, production and characterization of mycelial and extracellular FTases by Aspergillus oryzae IPT-301. Experimental design showed that the extracellular FTase performance was optimized (high transfructosylation activity and low hydrolytic activity) for reaction pH 5.5 - 6.75 and temperature of 45-50 °C and was fitted by the Michaelis-Menten model, while the mycelial FTase showed better performance at pH below 6.5 and temperature above 46 °C and was better fitted by the Hill model. The results obtained showed that the fungus represents a promising source for FOS production on a laboratorial scale.