Anaerobranca gottschalkii sp. nov., a novel thermoalkaliphilic bacterium that grows anaerobically at high pH and temperature.

Abstract

A novel thermoalkaliphilic, obligately anaerobic bacterium was isolated from a humid soil sample of a hot inlet of Lake Bogoria, Kenya. The newly isolated strain grows optimally at pH 9 5 and 50-55 SC and its growth range is pH 6 0-10 5 and 30-65 SC. Unlike the already known thermoalkaliphiles, the strain grows heterotrophically on a variety of mono-and polysaccharides (glucose, ribose, mannose, fructose, sucrose, maltose, starch, pullulan, xylan and cellulose) and on proteinaceous substrates such as yeast extract, peptone and tryptone. No dissimilatory sulfate reduction was observed, whereas thiosulfate was found to enhance growth when glucose or starch were used as substrates. Under optimal conditions, the doubling time is 48 min. Sodium ions are necessary for growth, with an optimal concentration of 230 mM (1 % NaCl, w/v) at pH 9 5. The rod-shaped cells are motile in the exponential growth phase under optimal growth conditions. Despite the Gram-negative staining and negative KOH assay, the strain is a Gram-positive organism, having an atypically thin cell wall. A sheath-like structure occurs at the cell separation area and parts of a surface layer-like structure were also observed. Based on physiological properties and molecular biological analysis, the strain falls within the radiation of the clostridia and represents a new species of Anaerobranca within the Clostridium/Bacillus subphylum of the Gram-positive bacteria. Strain LBS3 T (l DSM 13577 T ) is named Anaerobranca gottschalkii sp. nov. and is designated as the type strain.

Cloning, Sequencing, and Characterization of a Heat- and Alkali-Stable Type I Pullulanase from Anaerobranca gottschalkii

“…A. gottschalkii DSM 13577 and A. horikoshii DSM 9786 were grown anaerobically as previously described (15,48). Fermentation of A. gottschalkii was carried out in a 20-liter bioreactor with a continuous flow of N 2 -CO 2 (80:20, vol/vol) (48).…”

“…Since this strain grows heterotrophically on a variety of polysaccharides at pH 9.5 and 55°C, it is a suitable source for extracellular thermoalkalistable starch-hydrolyzing enzymes. However, although this bacterium is able to grow on pullulan, pullulanase activity was not detected in the culture supernatant (48). The closely related organism Anaerobranca horikoshii DSM 9786, isolated from Yellowstone National Park, is an obligate anaerobic thermoalkaliphilic bacterium whose optimum growth conditions are pH 8.5 and 57°C (15).…”

“…Anaerobranca gottschalkii DSM 13577 is an obligate anaer-obic thermoalkaliphilic bacterium that was isolated from a hot inlet of Lake Bogoria in Kenya (48). Since this strain grows heterotrophically on a variety of polysaccharides at pH 9.5 and 55°C, it is a suitable source for extracellular thermoalkalistable starch-hydrolyzing enzymes.…”

Anaerobranca zavarzinii sp. nov., an anaerobic, alkalithermophilic bacterium isolated from Kamchatka thermal fields

“…Electron micrographs revealed a Gram type positive cell wall (data not shown). Although phylogenetically belonging to the Gram type positive bacteria (Firmicutes) (Wiegel, 1981), species of the genus Anaerobranca stain either Gram-positive, as does the type species A. horikoshii (Engle et al, 1995), or stain Gramnegative at all growth phases as observed for strain JW/VK-KS5Y T , A. gottschalkii (Prowe & Antranikian, 2001) and A. californiensis (Gorlenko et al, 2004). No spores were observed using microscopy and in agreement with this observation, viability was lost after heat treatment at 80 uC for 10 min.…”

“…Being double extremophiles, alkalithermophiles are potential sources for novel enzymes as well as being model organisms for studying the origin of life and life on early Earth (Wiegel, 1998;Wiegel & Adams, 1998;Kevbrin et al, 2004). To date, the genus Anaerobranca (Firmicutes branch) is an example of a genus consisting entirely of anaerobic, alkalithermophilic species: Anaerobranca horikoshii (Engle et al, 1995), Anaerobranca gottschalkii (Prowe & Antranikian, 2001) and Anaerobranca californiensis (Gorlenko et al, 2004).…”