Syntrophobotulus glycolicus DSM 8271

Glycolate is an important constituent of fruit and sugar cane and is excreted by algae and autotrophic prokaryotes under conditions of carbon dioxide limitation and excess oxygen. While aerobic degradation of glycolate has been studied in detail, its anaerobic degradation has aroused interest only recently. Syntrophobotulus glycolicus strain FlGlyR was originally isolated from anoxic sewage sludge and later in pure culture with glyoxylate as its sole substrate. The nonmotile bacterium occurs typically as single cells or in small aggregates. Oval spores form in ageing cultures at the cell ends. While Gram staining is negative, ultrastructural analysis shows Gram-positive cell wall architecture. A strictly anaerobic bacteria, it grows chemotrophically in pure culture by fermentative oxidation of glyoxylate. Glycolate is oxidized in syntrophic coculture with, e.g., Methanospirillurn hungatei or Acetobacterium woodii as a partner. No other organic or inorganic substrates are used. Glycolic acid is converted to carbon dioxide and hydrogen in syntrophic culture; glyoxylic acid is fermented in pure culture to carbon dioxide, hydrogen, and glycolic acid. Glycolate oxidation to glyoxylate and vice versa is coupled to a membrane-bound electron transport system that catalyzes either a proton potential-driven reversed electron transport from glycolate to hydrogen or a hydrogen-dependent glyoxylate reduction coupled to ATP synthesis by electron transport phosphorylation. Does not reduce sulfate, sulfite, thiosulfate, elemental sulfur, or nitrate. Cells contain menaquinone-7-10, with MK-9 as major fraction, it contains no cytochromes. It grows in a pH range of 6.7 to 8.3 with optimum pH 7.3, its temperature growth range is 15 to 37 degrees C with an optimum of 28 degrees C. Growth optimal in freshwater medium; growth also occurs in brackish-water medium with 110 mM NaCl-5 mM MgCl(2) (adapted from PMID 88634369). (HAMAP: SYNGF)