GEOPHYSICAL MONOGRAPH SERIES, VOL. 144, PP. 213-226, 2004
Significance of polysaccharides in microbial physiology and the ecology of hydrothermal vent environments
Hyperthermophilic microorganisms (those with maximum growth temperatures of 90°C and above) are known to inhabit deep-sea
hydrothermal vent environments and are suspected of being present in the associated subsurface biosphere. One characteristic
of the growth physiology of many heterotrophic hyperthermophiles is the capacity to use complex polysaccharides (e.g., α-
and β-linked glucans as well as non-glucan hemicellulases) as carbon and energy sources. Polysaccharides may also play an
important ecological role in the deep-sea subsurface biosphere as the structural elements of biofilms harboring both heterotrophic
and chemolithotrophic microorganisms, representing a range of growth temperatures. Genome sequence analysis of several hyperthermophiles
indicates that the enzymatic machinery to synthesize and hydrolyze polysaccharides is present in this group of microorganisms.
This is supported by the biochemical characteristics of glycosidases from hyperthermophiles in addition to the observation
that several hyperthermophiles form biofilms in pure and co-culture. It remains to be seen if biofilms form the basis for
a subsurface biosphere but this possibility seems likely given the physiological characteristics of several hyperthermophiles
and mesophiles, representative of microorganisms previously isolated from vent sites.
Citation: Pysz, M. A.,