Classification of bacteria

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Classification seeks to describe the diversity of bacterial species by naming and grouping organisms based on similarities.


Bacteria can be classified on the basis of cell structure ,cellular metabolism or on differences in cell components such as DNA, fatty acids ,pigments ,antigens and quinones


Modern bacterial classification emphasizes molecular systematics, using genetic techniques such as GUANINE – CYTOSINE ratio determination , GENOME-GENOME hybridisation.


Classification of bacteria is determined by publication in the International Journal of Systematic Bacteriology and BERGEY’S manual of systematic bacteriology. The International Committee on systematic bacteriology maintains international rules for the naming of bacteria and taxonomic categories and for their ranking in the INTERNATIONAL CODE OF NOMENCLATURE OF BACTERIA.


HALOPHILIC BACTERIA: Halophiles are extremophile organisms that thrive in environments with very high concentrations of salt .


ACIDOPHILIC BACTERIA : Acidophiles are organisms that can withstand and even thrive in acidic environments where the pH values range from 1-5 Normally high acid levels destroy cells . EXAMPLE- T . acidophilus .


BAROPHILIC BACTERIA: Many microrganisms from the deep -sea display high-pressure-adapted - also described as barophilic or piezophilic growth characteristics. A large proportion of the barophilic bacteria currently in culture collections belong to a distinct subgroup of the genus Shewanella referred to as the barophile branch .EXAMPLE- Moritella yayanosii .