Joostella marina

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Higher order taxa

Bacteria; Bacteroidetes; Flavobacteria; Flavobacteriales; Flavobacteriaceae; Joostella:


Joostella Marina

Description and significance

Joostella marina is a bright yellow, gram negative, aerobic bacteria. Joostella marina is a member of the Flavobacteriacea family. This family is composed of at least 95 different genera including Joostella and 393 species. There are 80 genera containing 210 strains which grow in marine environments.

Joostella marina is a non-motile, rod shaped bacteria which forms colonies when possible. When Joostella marina does forms colonies, they appear translucent and shiny. The edges of these colonies are clearly defined. The cells themselves are usually 1.0-2.0 µm long and 0.20-0.30 µm wide. These bacteria do not form spores. The pigments produced by these cells are bright yellow and non-flexirubin-type.

Joostella marina is closely related to Galbibacter mesophilus and Zhouia amylolytica. These three microbes all belong to the Flavobacteriacea family and share 93% of the same DNA sequence. The DNA G+C content of Joostella marina is 30.1 mol%.


Joostella marina is a marine microbe found in coastal seawater in the East Sea of Korea. This microbe was discovered at a depth of 100 meters. The East Sea of Korea, also known as the Sea of Japan, is unique because it has virtually no tides. This is because it is almost completely closed off from the Pacific Ocean. This sea also has lower salinity and a higher concentration of dissolved oxygen than the oceans. These conditions allow for a wide array of aquatic life.

Because Joostella marina thrive in a marine environment, they prefer to have a steady supply of sodium. The concentration of sodium chloride which provides optimal growth is 1-3%, though Joostella marina is able to grow at concentrations of 0-15%. When exposed to high levels of sodium (18%) the cells do not survive. The pH range preferred by Joostella marina is 5.3-7.6. Temperature is also important for growth. These microbes prefer a temperature of 30 degrees Celsius though they are able to grow in temperatures ranging from 10 to 37 degrees Celsius.


Joostella marina is able to metabolize various sugars, allowing a wider array of food sources to be consumed. The carbon sources utilized by Joostella marina are glucose, sucrose, arabinose, mannose, and maltose. The major fatty acids are iso-C15:0, iso-C17:03-OH, and iso-C17:1v9c.

Current Research

Joostella marina was discovered by researchers in 2008. It is identified as strain En5T. Because this microbe is the only species that has been discovered so far in the Joostella genus, the size of the genus is not yet known. Besides the initial paper detailing its discovery and classification, no further research papers have been published on Joostella marina. However, the Flavobacteriacea family is being researched a significant amount. In 2006 alone 13 new genera and 20 new species were discovered, most of which came from marine environments.


1. "An Introduction to the Family Flavobacteriaceae". The Prokaryotes. New York: Springer. 2006. pp. 455–480.

2. Uda, Michitaka. "Sea of Japan (sea, Pacific Ocean)." Encyclopedia Britannica Online. N.p., n.d. Web. Mar. 2014.

3. Zhe-Xue Quan, Yi-Ping Xiao, et. al. "Joostella Marina Gen. Nov., Sp. Nov., a Novel Member of the Family Flavobacteriaceae Isolated from the East Sea." International Journal of Systematic and Evolutionary Microbiology. N.p., 2008. Web. Mar. 2014.

Edited by Kelsey O'Neil, student of Rachel Larsen at the University of Southern Maine