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HMC 2012 Enrichments & Isolations Presentation
Clostridia Enrichment
Guangfei Liu
Clostridium (Kloster/klwshr, Spindle)
梭
Shuttle
Endospores
Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes.
They are obligate anaerobes capable of producing endospores
Tortora et al. 2008. Microbiology An Introduction, 10th edition.
The Enrichment
The Enrichment
37 °C
The Enrichment
Pectins Utilization
OH
HOOC
O
HO
OH
OH
Galactouronic acid
Pectins
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
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
37 °C
80 °C
+ CO2
GYT Broth (g/L): 10.0 glucose; 5.0
tryptone; 10.0 yeast extract; 0.5
Na-thioglycolate; 20.0 CaCO3.
Fermentation
of
glucose
by
Clostridia. Glucose is degraded to
pyruvate via the Embden-Meyerhof
pathway
Lengeler et
Prokaryotes
al.
(2009)
Biology
of
the
3 ATP
Butyrate- + 2CO2 + 2H2 + H+
Glucose
ΔG°’ = -255 kJ/mol glucose (85 kJ/mol ATP)
4 ATP
2Acetate-+ 2CO2 + 4H2 + 2H+
Glucose + 2H2O
ΔG°’ = -206 kJ/mol glucose (52 kJ/mol ATP)
3.3 ATP
Glucose
0.7 Butyrate- +0.6 Acetate-+ 2CO2 + 2.6 H2 + 1.3 H+
ΔG°’ = -240 kJ/mol glucose (71 kJ/mol ATP)
Acid Production and Catalase Test
Clostridia
Negative
Propionic-acid-bacteria
Positive
Thank you!