Corynebacterium efficiens

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A Microbial Biorealm page on the genus Corynebacterium efficiens

Classification

Higher order taxa

Cellular organisms; Bacteria; Actinobacteria; Actinobacteria (class); Actinobacteridae; Actinomycetales; Corynebacterineae; Corynebacteriaceae; Corynebacterium; Corynebacterium efficiens

Species

NCBI: Taxonomy

Corynebacterium efficiens

Description and significance

Monosodium Glutamate is today mired in controversy as both a unique flavor enhancer and potential cause of human neurologic disorders.[1] As sides spar over this issue, the reality is production of L-gluatamine aka l-gln (the pre-cursor amino acid to MSG) is in excess of 1 million tons.[2] For many companies, the choice method of l-gln production is via fermentation of sugars by microorganisms. Most notable, are the microbes of the genus Corynebacterium. Species exploited for commercial production of l-gln have been Corynebacterium glutamicum and Corynebacterium callunae.[2,3] Ajinomoto, a Clinical Research Laboratory in Japan, have isolated three unique strains proven to be more efficient in l-gln production. (The details will be described in Biotech section) These three strains have been phylogenetically identified as a unique species of Corynebacterium, and are collectively named Corynebacterium efficiens.[2]

C. efficiens are gram-positive, non-motile cells. The isolates used to determine this new species were obtained from onion bulbs and soils of Kanagawa, Japan.[2] Grown on agar plates, the isolates are best grown between 30 and 40° C and appear as yellow, smooth, circular colonies.[2] As “coryneform” is literally translated to “club-shaped rods” in Greek, individual c. efficiens cells present as V-shaped rods caused by a “snapping” action during cell division.[2,4] C. efficiens is grown aerobically on simple media with glucose as the primary carbon source.

C. efficiens is of specific interest to companies involved in commercial production of amino acids because of its thermostability. The effectiveness of this species’ ability to grow efficiently at high temperatures has led to current genome sequencing to understand the genomic characteristics contributing to this organism’s thermostability. Scientists believe the key underlying c. efficiens thermostability will be invaluable for the development of thermostable protein synthesis.

Genome structure

C. efficiens has a single circular chromosome of approximately 3,147,090 bp and two plamids 23,743 bp and 48,672 bp in length.[2,5] The chromosome has a G+C content of 63% and the plasmids have a G+C content of 54% and 56%. This high G+C content is thought to play a factor in the thermostability of the organism.[2] The average Open Reading Frame for the chromosome is 981 bp. The average ORF for Plasmid 1 is 1,155 bp and plasmid 2 is 924 bp.

The genome structure plays an important role in identification of this specific species. Comparing 16S rDNA genome sequences of c. efficiens vs. the Corynebacterium genus reveal that the isolates of C. efficiens belong to the “glutamic-acid producing species".[2,6] Of these acid producing species, c. efficiens was 95.3 % similar to c. glutamicum. This is lower than the criteria used to define identical bacterial species (97%).[2] The importance of high G+C content will be discussed in “Cell structure and Metabolism”

C. efficiens genetic data is obtained from bacterial strain YS-314 [2]

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.

Ecology

Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Rachel Larsen