04-09-2012, 11:30 AM
Sporosarcina pasteurii
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Sporosarcina pasteurii formerly known as Bacillus pasteurii from older taxonomies, is a bacterium with the ability to precipitate calcite and solidify sand given a calcium source and urea, through the process of biological cementation.[1] S. pasteurii has been proposed to be used as an ecologically sound biological construction material.
Possible applications
Desertification examplified by sand dunes advancing on Nouakchott, the capital of Mauritania
Architecture student Magnus Larsson won the 2008 Holcim Award "Next Generation" first prize for region Africa Middle East for his project "Dune anti-desertification architecture, Sokoto, Nigeria" and his design of a habitable wall.[2] Larssons also presented the proposal at TED.[3]
Another potential application is to solidify liquefiable soils in areas prone to earthquakes
Description and Significance
M. luteus can be found in many places such as the human skin, water, dust, and soil. Micrococcus is generally thought of as harmless bacterium, but there have been rare cases of Micrococcus infections in people with compromised immune systems, as occurs with HIV patients.
Genome Structure
Hybridization studies show no close genetic relationship among the species of Micrococcus. For example, M. luteus and M. lylae are 40-50% genetically different. M. luteus has a G-C content of 65-75 mol%. About half of the strains of M. luteus were found to carry plasmids 1 to 100MDa in size. So far two genome sequences have been done, one on Micrococcus sp. 28 plasmid pSD10 and another on Micrococcus luteus plasmid pMLU1.
Cell Structure and Metabolism
Micrococcus are Gram-positive cocci that are 0.5 to 3.5 micrometers in diameter and usually arranged in tetrads or irregular clusters. They are generally strict aerobes and can generally reduce nitrate. M. luteus oxidizes carbohydrates to CO2 and water, and it does not produce acid from glucose as well as it does not make arginine dihydrolase or b-galactosidase. Some Micrococcus are pigmented bacteria; for example, M. luteus produces yellow colonies and M. roseus produces redish colonies. Micrococcus species are oxidase-positive, which can be used to distinguish them from other bacteria like most Staphylococcus species, which are generally oxidase-negative. Defining characteristics of Micrococcus are the ability to aerobically produce acid from glucose glycerol, aesculin hydrolysis, arginine dihydrolase, major pigment production, motility, and conversion of nitrate to nitrite (Smith et al. 1999).