Estudante

Quim. Nova, Vol. 30, No. 1, 136-145, 2007 ENZIMAS TERMOESTÁVEIS: FONTES, PRODUÇÃO E APLICAÇÃO INDUSTRIAL

Revisão

Eleni Gomes*, Marcelo Andrés Umsza Guez, Natalia Martin e Roberto da Silva Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, R. Cristóvão Colombo, 2265, 15054-000 São José do Rio Preto – SP, Brasil Recebido em 28/9/05; aceito em 24/3/06; publicado na web em 30/8/06

THERMOSTABLE ENZYMES: SOURCES, PRODUCTION AND INDUSTRIAL APPLICATIONS - REVIEW: Living organisms encountered in hostile environments that are characterized by extreme temperatures rely on novel molecular mechanisms to enhance the thermal stability of their proteins, nucleic acids, lipids and cell membranes. Proteins isolated from thermophilic organisms usually exhibit higher intrinsic thermal stabilities than their counterparts isolated from mesophilic organisms. Although the molecular basis of protein thermostability is only partially understood, structural studies have suggested that the factors that may contribute to enhance protein thermostability mainly include hydrophobic packing, enhanced secondary structure propensity, helix dipole stabilization, absence of residues sensitive to oxidation or deamination, and increased electrostatic interactions. Thermostable enzymes such as amylases, xylanases and pectinases isolated from thermophilic organisms are potentially of interest in the optimization of industrial processes due to their enhanced stability. In the present review, an attempt is made to delineate the structural factors that increase enzyme thermostability and to document the research results in the production of these enzymes. Keywords: thermostable enzyme; thermophilic microorganism; thermal adaptation.

INTRODUÇÃO Em contraste com outros grupos de organismos vivos, os microrganismos apresentam grande capacidade adaptativa colonizando ambientes nos quais outras formas de vida não seriam viáveis, como os ambientes geotérmicos. A