Colorless Sulfur BacteriaColorless Sulfur BacteriaBlanca PérezBlanca Pérez

Hopkins Microbiology Course 2010Hopkins Microbiology Course 2010

Colorless Sulfur Bacteria

Comprises a very heterogeneous group of chemoautotrophic bacteria

Use of reduced forms of S as e- source

Most of them require O2 as e- acceptor, but a few are able to grow anaerobically using nitrogen oxides

Sulfur cycle, Robertson and Keuenen (2006)

Colorless Sulfur Bacteria Thiobacillus Thiomicrospira Thiosphaera Sulfolobus Acidianus Thermothrix Thiovulum Beggiatoa Thiothrix Thioploca Thiodendron Thiobacterium Macromonas Achromatium Thiospira

Will

Gradient tubes

H2S

O2

Interface between opposing oxygen and sulfide gradients

H2S + 2O2 SO42- + 2H+

Gradient tubes

Kosh

Gradient tubes

Hyansoo

Spirocheta sp.

symbiotic relationships between Spirochaeta plicatilis with Beggiatoa

Thiosulfate plates Use of thiosulfate as e- donor (with O2 or NO3

- as e- acceptor) Production of sulfuric acid (bromothymol blue)

Aerobic incubation (w/o NO3-) Anaerobic incubation (w NO3

-)

Thiosulfate plates: aerobic conditions

2 days

Na2S2O3 + 2O2 + H2O Na2SO4 + H2SO4

Sulfuric acid

Thiosulfate plates: anaerobic conditions

Aerobic incubation

~2 weeks

Sulfuric acid

Elemental sulfur

Thiosulfate plates

Colorless Sulfur BacteriaColorless Sulfur BacteriaBlanca PérezBlanca Pérez

Hopkins Microbiology Course 2010Hopkins Microbiology Course 2010

Desulfovibrio sulfodismutans

can grow anaerobically by the disproportionation of thiosulfate to sulfate and sulfide

Sulfate Reducing Bacteria: disproportionation of thiosulfate