HCO 3 − Fixation by Naturally Occurring Tufts and Pure Cultures of Thiothrix nivea

• Published in: Applied and environmental microbiology Vol. 56; no. 3; pp. 730 - 738
• Main Authors: McGlannan, Michael F., Makemson, John C.
• Format: Journal Article
• Language: English
• Published: 01.03.1990
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/aem.56.3.730-738.1990

Naturally occurring tufts of the mixotroph Thiothrix nivea blanketed the East Everglades (Dade County, Fla.) Chekika artesian well and runoff areas. The rate of HCO 3 − fixation by these Thiothrix tufts was determined to be 14.0 ± 5.4 nmol of HCO 3 − per min per mg of dry weight, which reflected a growth rate of 5.0%/h. The addition of 10 mM glucose, ribose, acetate, or pyruvate or 0.05% Casamino Acids (Difco Laboratories, Detroit, Mich.) did not appear to alter the HCO 3 − fixation rate. Whereas 1 mM acetate or 10 mM lactate, ethanol, glycerol, α-ketoglutarate, succinate, fumarate, or citrate slightly stimulated HCO 3 − fixation, 5 to 10 mM malate inhibited HCO 3 − fixation by 90%. Pure Thiothrix cultures isolated from Chekika fixed HCO 3 − at rates as high as 29.9 ± 2.8 nmol of HCO 3 − per min per mg of dry weight in the presence of growth medium. Malate did not have a suppressive effect but rather slightly stimulated in vivo HCO 3 − fixation.