Clostridium schirmacherense sp. nov., an obligately anaerobic, proteolytic, psychrophilic bacterium isolated from lake sediment of Schirmacher Oasis, Antarctica

• Main Authors: Alam, Syed Imteyaz, Dixit, Aparna, Reddy, G. S. N., Dube, S., Palit, Meehir, Shivaji, S., Singh, Lokendra
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Society for General Microbiology 2006
• Subjects: QL Zoology; Antarc*; Antarctica
• Online Access: http://repository.ias.ac.in/64276/; http://ijs.sgmjournals.org/content/56/4/715.abstract?sid=d2c82c26-071c-4e6c-9528-e121daa97f64

A novel obligately anaerobic, proteolytic bacterium, designated AP15 T , was isolated from lake sediments of Schirmacher Oasis, Antarctica. The bacterium produced maximum cell mass between 5 and 10°C in an anaerobic basal medium containing 0.5% tryptone and peptone. The strain grew optimally at a pH around 8·0 and tolerated NaCl up to a concentration of 7·5%. It contained diphosphatidylglycerol as the major phospholipid and C 15:0 , C 16:0 and C 17:0 as the major cellular fatty acids. Several amino acids, including arginine, leucine, isoleucine, cysteine, glutamate and serine, supported growth. Glutamate was degraded to acetate, propionate, CO 2 and H 2 . In addition, the strain degraded carbohydrates including glucose, raffinose, adonitol, ribose and rhamnose. The main fermentation products during growth on glucose were H 2 , CO 2 , formate, acetate, propionate and isovalerate. The DNA G+C content of the bacterium was 24 mol%. On the basis of a phylogenetic analysis, strain AP15 T is identified as a close relative of Clostridium subterminale ATCC 25774 T , with which it shares 99·5% similarity at the 16S rRNA gene sequence level; however, it exhibits a low DNA-DNA binding value (55%) to this strain at the whole-genome level. In addition to showing other major differences with respect to C. subterminale and other members of the genus Clostridium, AP15 T also exhibits phenotypic differences. On the basis of these differences, strain AP15 T is identified as representing a novel species of the genus Clostridium, for which the name Clostridium schirmacherense sp. nov. is proposed. The type strain is AP15 T (=DSM 17394 T =JCM 13289T).