Estudo da recuperação de frutose produzida na sintese enzimatica "in vitro" de dextrana

AUTOR(ES)
DATA DE PUBLICAÇÃO

1999

RESUMO

Dextran is a biopolymer from bacteriological origin, with great industrial potential. It is mainly produced by the enzime dextran sucrose from Leuconostoc mesenteroids. It manly formed by glucose residues linked by a-1,6 bonds. This polysaccharide has many uses today, for example in many foods, pharmaceutics products, cosmetics, chemical and photographic industries. The characteristics as well as properties of dextran are very specific and its use is different for each molecular weight range. In the enzymatic synthesis from sucrose, fructose as by-product is obtained and this monosaccharide is used in food industries. However, very few studies about separation of the fructose from dextran medium can be found in the literature. The fructose recovery will provide a substantial savings for the process as a whole. The objective of this work is to select and study resins that provides the fructose separation from the medium. Dextran sucrase, was produced by Leuconostoc mesenteroides NRRL B512-F on sucrose, and used in the dextran synthesis. The enzymatic reaction was realized with 10% sucrose solution, in pH 5,2 and 20°C. The dextran direct synthesis product was separated in a glass chromatographic column, packed lither with Dowex 50W X4 ion excihange resin, Dowex 50W X8, Dowex 40285 resin or Superdex 30 from Pharmacia Biothec. The original hidrogens resins were changed by calcium ions. Separation occurred at elution rate of 0,1 and 0,55 ml/min at temperatures of 35, 45 e 60°C; and the separation with Superdex 30 gel column was performed at 45°C. The separation samples were colected at defined intervals of time and analysed by gel permeation chromatography, in an HPLC system in order to obtain the fructose concentration profile. It has been shown that there are an increase in the separation efficiency when the temperature is increased at a flow rate of 0,1 ml/min. The best result was obtained with Dowex 40285 resin, to flow at 0,1 ml/min at a temperature of 60°C

ASSUNTO(S)

frutose separação (tecnologia) biopolimeros

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