Production and Characterization of an Extracellular β-d-Fructofuranosidase fromFusarium GraminearumDuring Solid-State Fermentation Using Wheat Bran as a Carbon Source

Abstract

The search for new sources of β-d-fructofuranosidases with potential for utilization in the food and beverage industries is an important task. The filamentous fungus Fusarium graminearum was recently reported to produce β-d-fructofuranosidase with suitable properties for biotechnological applications. Therefore, the objective of this study was to purify and characterize F. graminearum β-d-fructofuranosidase. High levels of the enzyme were obtained in Solid-State Fermentation (at 30C for 7 days) using wheat bran as a carbon source. The extracellular enzyme was purified 8-fold with 14% recovery using ethanol precipitation, diethylaminoethyl-Cellulose, and Sephacryl S-200. The optimum temperature and pH for the heterodimeric protein (94 kDa and 66 kDa), were 55–60C and 4.5, respectively. The enzyme was stable at 30–50C for 1 h, and at pH 3.0–8.0. Enzymatic activity was enhanced by Mn2+ (127%) and was inhibited by Hg2+. The Km values were 31.6 and 24.1 mM for sucrose and raffinose, respectively. Practical Applications β-d-Fructofuranosidases are enzymes with a wide range of industrial applications, especially in the food and beverage industries. These enzymes catalyze the hydrolysis of sucrose to invert sugar syrup. In addition, some β-d-fructofuranosidases can catalyze transfructosylation reaction for production of fructooligosaccharides (FOSes). Both invert sugar and FOSes are important materials for the food industry. The main sources of β-d-fructofuranosidase are microorganisms; the filamentous fungus Fusarium graminearum is a new source of β-d-fructofuranosidase with attractive properties for practical applications. The characterization of F. graminearum β-d-fructofuranosidase is an important step to determine its potential practical applications.