Extracellular β-D-fructofuranosidase from Aspergillus parasiticus: Optimization of the production under submerged fermentation and biochemical characterization

Abstract

The β-D-fructofuranosidases are enzymes with biotechnological potential that can be used in different industrial sectors as food and beverage. In this context, microorganisms are important producers of these biomolecules, especially filamentous fungi. The production of extracellular β-Dfructofuranosidase from Aspergillus parasiticus using sugarcane bagasse as a carbon source under submerged fermentation was optimized by factorial design and high levels of enzyme were obtained in 24 h-old cultures at 30°C using 1.5% sugarcane bagasse under agitation. The extracellular β-Dfructofuranosidase was purified 119-fold using diethyl aminoethyl (DEAE)-cellulose and Sephacryl S-200 chromatographic columns with recovery of 16%. The native molecular mass was estimated as 136 kDa with two subunits of 63 kDa determined by 7% sodium dodecyl sulfate poly-acrylamide gel electrophoresis (SDS-PAGE) and 64% carbohydrate content. The purified enzyme showed optimal temperature of activity from 38-56°C and optimum pH from 4.5 to 6.2 determined by experimental design (CCRD), with half-life of 25 min at 50°C. It was stable from pH 5.0-10.0. The extracellular enzyme activity was stimulated by Ba²⁺ and Mg²⁺, and it was not affected by urea, silver and ethylenediaminetetraacetic acid (EDTA). The K_0.5 and V_max values were 10 mM and 1565 U/mg of protein, and 19 mM and 1965 U/mg of protein for sucrose and raffinose, respectively.

Keywords: Invertase, fructofuranosidase, Aspergillus parasiticus, sugarcane bagasse, factorial design.

African Journal of Biotechnology Vol. 12(38), pp. 5678-5687