Imobilização da tanase de Paecilomyces variotii e ação em reações de hidrólise e síntese / Immobilization of tannase from Pecilomyces variotii and reactions of hydrolysis and synthesis

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

06/06/2012

RESUMO

Tannin acyl hydrolase (TAH) known as tannase (EC 3.1.1.20) is an enzyme that hydrolyzes esters of hydrolysable tannins producing gallic acid and glucose as the reaction medium is polar. However, the literature indicates their ability to produce also gallic acid esters in organic media. Our research group has isolated a fungus, Paecilomyces variotii, tannase producer in 2005 and since then has been conducting studies of production, purification, characterization and applications of this enzyme. Continuing the research, the objective of this work was study a process to immobilize tannase from Paecilomyces variotii using different supports and techniques. Were evaluated the parameters of the immobilization process, free and immobilized tannase were characterized biochemically and yet been investigated quimioseletivity of tannase immobilized and free for synthesis reactions. Tannase was immobilized by adsorption onto alumina, Amberlite, Accurel and celite, by covalent binding in Amberlite and Dowex activated with polyethyleneimine and glutaraldehyde on silica, celite and Accurel activated with glutaraldehyde and 3-aminopropyltriethoxysilane and ionic gelation by sodium alginate, alginate from brown seaweed, carrageenan, chitosan, pectin and gellan gum. The immobilized tannase was evaluated as the percentage of enzyme activity and percentage of immobilization efficiency. The immobilization process of tannase in sodium alginate was optimized using the experimental design method. After the optimization process the tannase immobilized in alginate was evaluated for reuse and characterized biochemically for pH and temperature optima for activity and stability and the activity against inhibitors. In addition to the immobilization process, we evaluated the effect of the use of cross-linking: genipin, glutaraldehyde, Transglutaminase Activa ® and the transglutaminase from Streptomyces sp. CBMAI 837. The capsules obtained were evaluated for percentage of enzymatic activity, percentage of immobilization efficiency and their morphology was studied by scanning electron microscopy. Among the carriers used for immobilization of tannase by adsorption, covalent and ionic gelation has been a higher percentage of enzyme activity using the supports celite, silica activated with glutaraldehyde and 3-aminopropyltriethoxysilane and sodium alginate, respectively. The optimal conditions for immobilization of tannase in sodium alginate were 3.6% sodium alginate, calcium chloride 0.1 M, 3.6 mg of tannase / mL alginate and 6h of cure. After the optimization process, the tannase activity increased by 35 times. The tannase immobilized on sodium alginate in the optimized conditions can be reused up to 5X keeping 60% of its catalytic activity, the capsules showed greater stability for pH, temperature and inhibitors compared with free tannase. Finally, we evaluated the ability of free and immobilized tannase in synthesizing esters of gallic acid. The free tannase proved to be effective in the synthesis of gallates, especially propyl gallate with a percentage of esterification of 65%, with the immobilized tannase in sodium alginate was observed only 8% of propyl gallate esterification

ASSUNTO(S)

tanase imobilização síntese hidrólise encapsulação tannase immobilization synthesis hydrolysis encapsulation

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