CHARACTERIZATION OF THE XYLANOLYTIC ENZYME-SYSTEM OF THE EXTREME THERMOPHILIC ANAEROBIC-BACTERIA THERMOTOGA-MARITIMA, T-NEAPOLITANA, AND T-THERMARUM

The extreme thermophilic anaerobic bacteria Thermotoga maritima, T. ne apolitana, and T. thermarum when grown on xylan produce extremely ther moactive xylanases, beta-xylosidases and alpha-arabinofuranosidases. M ost of these enzymes are active over a broad temperature and pH range, namely between 40 and 110 degrees C and pH 4 to 9. The xylanases are active towards soluble, as well as insoluble xylan. Unlike the enzyme system of T. maritima and T. thermarum, the xylanase activity of T. ne apolitana is activated (up to 211%) in the presence of Ca2+, Mg2+, Co2 +, and Mn2+. The xylanolytic enzyme system of T. thermarum is inactive towards cellulose. Xylan hydrolysis experiments indicate the presence of endoxylanases in the enzyme preparation of all strains investigate d, with the main products being xylobiose, xylotriose, and larger xylo oligosaccharides. (C) 1997 Elsevier Science Inc.