Desulfurococcus kamchatkensis sp. nov., a novel hyperthermophilic protein-degrading archaeon isolated from a Kamchatka hot spring

Abstract

A novel obligately anaerobic, hyperthermophilic, organotrophic archaeon, designated strain 1221n T , was isolated from a hot spring of Uzon Caldera (Kamchatka Peninsula, Russia). Cells of strain 1221n T were non-motile regular cocci, 0.6-1 mm in diameter. The temperature range for

Complete Genome Sequence of the Anaerobic, Protein-Degrading Hyperthermophilic Crenarchaeon Desulfurococcus kamchatkensis

“…None of these enzymes is predicted to contain a N-terminal signal sequence, and thus they are not expected to act outside the cell. This agrees with the observation that D. kamchatkensis is unable to grow on microcrystalline cellulose, carboxymethyl cellulose or cellobiose (21). Probably, the above enzymes are involved in intracellular processing of polysaccharides.…”

“…This agrees with the ability of D. kamchatkensis to grow on the linear ␣-(1,4)-linked D-glucose polymer dextrin and the ␣-(1,4), ␣-(1,6)-linked D-glucose polymer dextran (21). Presumably, the resulting lower molecular weight dextrins can be imported into the cells by the function of the ABC-type maltose and maltodextrin transport system.…”

“…Group II enzymes hydrolyze maltooligosaccharides, unlike the group I enzymes (54). Maltose cannot be utilized by D. kamchatkensis (21); consequently, Dkam_0582 most likely represents group I of microbial ␣-glucosidases.…”

“…In the presence of elemental sulfur, H 2 S is formed instead of H 2 . A detailed phenotypic description of D. kamchatkensis was presented previously (21).…”

Complete Genome Sequence of Desulfurococcus fermentans, a Hyperthermophilic Cellulolytic Crenarchaeon Isolated from a Freshwater Hot Spring in Kamchatka, Russia

“…It ferments cellulose and various other carbohydrates (fructose, lactose, maltose, ribose, and starch) and peptides in peptone and casein hydrolysate for growth and produces hydrogen in the process (6); hydrogen production is not impeded by hydrogen accumulation (6). In contrast, other Desulfurococcus species do not utilize cellulose, are inhibited by hydrogen, and require elemental sulfur for growth (1,4,6,7,9); reduction of sulfur to H 2 S removes inhibition by hydrogen. D. fermentans neither requires nor is stimulated by elemental sulfur (6).…”