Clostridia Enrichment

Guangfei Liu

HMC 2012 Enrichments & Isolations Presentation

Clostridium (Kloster/, Spindle)

梭 Shuttle

Endospores

Tortora et al. 2008. Microbiology An Introduction, 10th edition.

Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores

The Enrichment

The Enrichment

37 °C

The Enrichment

Pectins Utilization

Pectins are linear polysaccharides derived from galactouronic acid units, where some of the carboxylic acid groups are esterified with methanol. During fermentation, the ester groups are hydrolyzed, and methanol is released

OH

HO

OHOH

HOOC

O

Galactouronic acid Pectins

Methanol was the major nongaseous end product produced by some of the species examined. For C. buwricum strain 4P1 on pectin (mM): 16, methanol; 11.4, butyrate; 7.5, acetate; 2.3, ethanol; 0.8, lactate; and 0.7, isopropanol. The methanol produced by the species examined here was not further consumed. In control experiments, these species did not grow on methanol as energy source.

Inoculation and Incubation

80 °C

37 °C

+ CO2

Fermentation of glucose by Clostridia. Glucose is degraded to pyruvate via the Embden-Meyerhof pathway

Lengeler et al. (2009) Biology of the Prokaryotes

GYT Broth (g/L): 10.0 glucose; 5.0 tryptone; 10.0 yeast extract; 0.5 Na-thioglycolate; 20.0 CaCO3.

Glucose Butyrate- + 2CO2 + 2H2 + H+

ΔG°’ = -255 kJ/mol glucose (85 kJ/mol ATP)

Glucose + 2H2O 2Acetate-+ 2CO2 + 4H2 + 2H+

ΔG°’ = -206 kJ/mol glucose (52 kJ/mol ATP)

3 ATP

4 ATP

Glucose 0.7 Butyrate- +0.6 Acetate-+ 2CO2 + 2.6 H2

+ 1.3 H+

ΔG°’ = -240 kJ/mol glucose (71 kJ/mol ATP)

3.3 ATP

Acid Production and Catalase Test

Negative Positive

Propionic-acid-bacteriaClostridia

Thank you!