Production and Characterization of an Extracellular β‐ d ‐Fructofuranosidase from Fusarium Graminearum During Solid‐State Fermentation Using Wheat Bran as a Carbon Source

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 Mn 2+ (127%) and was inhibited by Hg 2+ . The K m 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.