RESUMO
Naringinase is a complex enzyme composed of α-L-rhamnosidase and ß-D-glucosidase, which has a vast potential application in the field of industrial biotechnology. The novel aspect in the present study is employing a three-phase partitioning (TPP) technique for the purification of naringinase by solid-state fermentation using Aspergillus brasiliensis MTCC 1344. At optimum conditions of 28±2 °C and 30% (w/v) ammonium sulfate along with a 1:1 ratio of t-butanol to crude extract, the purification is enhanced by 4.2-fold .Temperature and pH profile of TPP purified naringinase was found to be active with an optimal activity of 719.6 units at an elevated temperature of 60 °C. The kinetic constants K(m) and V(max) using naringin as substrate were 3.21 mM and 321 U/ml. The purified enzyme was not inhibited by any metal ions except Hg(2+) but completely inhibited by adding chelating agents such as EDTA and SDS at a concentration of 10 mM. These results can be inevitable to establish the TPP method to be an inexpensive, economical and attractive technology for better recovery and to find its application in the industrial sector.
Assuntos
Proteínas Fúngicas/química , Complexos Multienzimáticos/química , beta-Glucosidase/química , Aspergillus/enzimologia , Precipitação Química , Estabilidade Enzimática , Proteínas Fúngicas/isolamento & purificação , Meia-Vida , Concentração de Íons de Hidrogênio , Cinética , Extração Líquido-Líquido , Metais Pesados/química , Complexos Multienzimáticos/isolamento & purificação , beta-Glucosidase/isolamento & purificaçãoRESUMO
Statistics based optimization, Plackett-Burman design (PBD) and response surface methodology (RSM) were employed to screen and optimize the media components for the production of naringinase from Aspergillus brasiliensis MTCC 1344, using solid state fermentation. Cassava waste (CW) was used as both the solid support and carbon source for the growth of A. brasiliensis. Based on the positive influence of the Pareto chart obtained from PBD on naringinase activity, three media components--maltose, peptone and calcium chloride were screened. Box-Behnken design (BBD) was employed using these three factors at three levels, for further optimization, and the second order polynomial equation was derived, based on the experimental data. Derringer's desired function methodology showed that the concentrations of maltose (7.74 g/L), peptone (4.19 g/L) and calcium chloride (7.63 mM) were the optimal levels for maximal naringinase activity (889.91 U/mg) which were validated through experiments.