Arthrobacter (from the Greek, "jointed small stick”) is a genus of bacteria that is commonly found in soil. All species in this genus are Gram-positive obligate aerobes that are rods during exponential growth and cocci in their stationary phase.
Colonies of Arthrobacter have a greenish metallic center on mineral salts pyridone broth incubated at 20 °C (68 °F). This genus is distinctive because of its unusual habit of "snapping division" in which the outer bacterial cell wall ruptures at a joint (hence its name). Microbiologists refer to the type of cell division in which rods break into cocci as reversion. Under the microscope, these dividing cells appear as chevrons ("V" shapes). Other notable characteristics are that it can use pyridone as its sole carbon source, and that its cocci are resistant to desiccation and starvation.
In a bioprocess, one requires two important things: cells and media.
The production of L-glutamate can utilise a large variety of bacterial strains, from many different genera and type. In the past, bacteria from the Brevibacterium, Arthrobacter, Microbacterium and Corynebacterium genera have been exploited for this purpose. The most commonly used bacterial strain today, however, is Corynebacterium glutamicum, previously known as Micrococcus glutamicum. As a non-pathogenic coryneform bacterium, C. glutamicum is a popular choice of bacteria for several other amino acids as well.
As for growth media, the choices are many. A major concern of large-scale manufacturers is the cost of the media, and so they prefer to use sugar sources such as cane or beet molasses, starch hydrolysates from corn or cassava tubers, or even tapioca. The choice of sugar source essentially depends on whatever is most readily available. Generally, a manufacturer will use a sugar source from a regional plant source. Along with sugar, ammonia and ammonium salts are added as a nitrogen source. The vitamins, minerals, and some other types of nutrients can be easily and cheaply provided by adding corn steep liquour.
Arthrobacter chlorophenolicus sp. nov., a species capable of degrading high concentrations of 4-chlorophenol, may also be useful in bioremediation. Arthrobacter sp. strain R1 (American Type Culture Collection strain number 49987) has been shown to grow on a variety of aromatic compounds, including homocyclic compounds, such as hydroxybenzoates, as well as N-heterocycles, including pyridine and picoline. This bacterium produces a dark pigment when grown on pyridine, but not simple substrates, such as succinic acid.
Arthrobacter sp H65-7 produces the enzyme inulase II that converts inulin into difructose anhydride (DFA). DFA is a promising nutrient for fighting osteoporis, because it helps absorption of calcium in the intestines.
The enzyme Alu obtained from Arthrobacter luteus is able to cleave Alu sequences in human DNA, causing the kind of gene sequence to be named after the enzyme. Alu are a group of moderately repetitive gene sequences (300bp in length). Alu sequences make up 6-8% of the human genome.
- LPSN bacterio.net
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- Marks A. Basic Medical Biochemistry: a Clinical Approach 3ed, p. 248.