Resumo

Currently, biotechnology is accompanied by studies on the function, structure and utilization, of enzymes obtained from microorganisms, which have raised interest in research that might improve and optimize the production of these proteins. Among these enzymes, the β-D-fructofuranosidase (EC 3.2.1.26), also known as invertase, catalyzes the hydrolysis of sucrose molecule to obtain a mixture of D-glucose and D-fructose, the inverted sugar. These enzyme, also can be used in the production of prebiotics fructooligosaccharides (FOS), which are sugars not metabolized by the human organism and they have no caloric value and promotes the reduction of serum cholesterol and prevent some cancers. The aim of this work was to study the production of invertase by F. graminearum under Solid State Fermantation (SSF) and the temperature and pH stabilities of invertase immobilizeted in alternative supports. F. graminearum produced high levels of extracellular enzyme (110.3 U/g of substrate) under SSF moistened with tap water (1:1, w/v), at 30oC and 60% relative humidity for 7 days, using wheat bran as substrate/carbon source. The crude extract containing F. graminearum invertase was immobilized using domestic cotton, filter paper, cloth multipurpose, sugar cane bagasse, string, gauze, and cyanogen bromine agarose (BrCN) as supports. The supports were activated with polyethylenimine (PEI) 0.2% (v/v) and cross-linked using glutaraldehyde (2% v/v). All derivates showed high capacity for reuse for up to 25 times. The invertase immobilized in cloth multipurpose and string was stable above 80% residual activity at 60°C for more than 120 min and the filter paper derivate showed T50 of 27 min at 70°C. For all pH tested the immobilized invertase was more stable than the free enzyme. At pH 3.0 the derivates cotton and cloth multipurpose showed T50 of 120 min and at pH 9.0, T50 was around 45 min for all derivates, except cotton. The use of immobilized enzymes on alternative supports as shown for F. graminearum invertase for industrial application is very interesting. It originates from the disadvantages of the use of many materials, such synthetic, non-biodegradable and toxic or those that giving the product undesired properties such as color, flavor and taste, which makes them unsuitable for immobilization particularly in the food and pharmaceutical industries.