A novel thermophilic anaerobic, rod-shaped, non-spore forming, gram positive bacterium was isolated from an oil field in Turkey, that produces cyclodextrin glycosyltransferase (CGTase) from starch. According to the some morphological, biochemical and 16S rRNA analysis, the strain belongs to the genus Thermoanaerobacter. The strain mainly utilizes starch and derivatives, glucose and fructose as carbon source between 45 and 75 degrees C, optimally at 65 degrees C. Optimum pH for growth is 7.5.16S RNA studies indicate that the bacterium has a similarity of 98.3% to homoacetogenic Thermoanaerobacter kivui and the main fermentation product is acetic acid as in the case with homoacetogenic bacteria. The main difference between the bacterium and T kivui concerns the utilization of starch. Based on the phylogenetic and biochemical analysis, it is proposed that the species are a new member of the genus Thermoanaerobacter. The strain has CGTase activity optimum at 80 degrees C and pH 7.0-8.0. (C) 2008 Elsevier Ltd. All rights reserved