Growth studies of Wolinella recta, a gram‐negative periodontopathogen

The effects of varying concentrations of ammonium formate, fumarate, nitrate, pyruvate and hemin, on growth and end‐product formation in Wolinella recta ATCC 33238 were examined. Mycoplasma broth base supplemented with 30 mM formate and 20 mM fumarate supported growth of W. recta to an optical density of 0.471 with a generation time of 2.15 h. Increasing formate and fumarate concentrations to 150 mM and 75 mM, respectively, resulted in a maximum optical density of 0.600. Neither stirring nor the addition of pyruvate, enhanced growth. Hemin was not required for growth. Growth of W. recta in a defined medium required the addition of at least 0.4% yeast extract. In both complex and defined media, fumarate supported significantly higher maximum optical densities than nitrate. The omission of formate from the growth medium or the adjustment of the pH of the medium to 6.6 resulted in essentially no growth of W. recta. The metabolic products of growth on nitrate and fumarate were nitrite and succinate, with ammonia and hydrogen sulfide also being observed. Growth in all media was accompanied by increases in pH to a maximum of 8.0.