Geobacillus kaustophilus

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A Microbial Biorealm page on the genus Geobacillus kaustophilus

Contents

Classification

Higher order taxa

Domain: Bacteria; Phylum: Firmicutes; Class: Bacilli; Order: Bacilla; family:Bacillaceae [Others may be used. Use NCBI link to find]


Species

NCBI: Taxonomy

Genus: Geobacillus species: kaustophilus

Description and significance

This microbe was isolated from the deep-sea sediment of the Mariana Trench (2). Its optimal growth is at a temperature of 60 degrees Celsius with a temperature limit of 74 degrees Celsius (2). Bacillus is translated as “small rod,” and geo is “earth” or “soil” so the genus name is roughly translated to earth or soil small rod (6). In its species name, “kausto” means “heat” while “philus” means love (2). Therefore, it is a heating-loving bacteria. Geobacillus kaustophilus grow in aquatic environments. Other species in the genus Geobacillus can also be found in petroleum reservoirs and cool soil environments (3). Species in the Geobacillus genus can live in a wide variety of environments. The microbe can withstand a pH of 2 through 12, temperatures between 5 and 78 degrees Celsius, and a salinity of 0 to 30% (5).

Genome structure

Geobacillus kaustophilus contains a 3.54Mb chromosome. It is circular and has 3,544,776 base pairs. The microbe also consists of a 47.9kb plasmid. This, too, is circular and has 47,890 base pairs (2). After its genome was sequenced, the genes for protamine, spermine synthase, and tRNA methyltranferase were found. These genes are believed to have a role in the DNA/RNA stability of the microbe at high temperatures (2). The protamine-like gene, in particular, is unique to Geobacilus kaustophilus (5). Protamines enble the DNA of an organism to be more compact by binding to it. Spermine also plays a part in DNA stability and is the major polyamine in the microbe while tRNA methyltranferase is responsible for the thermoadaptation of the microbe to its environment (5). Researchers have founded 3498 protein-coding sequences in Geobacillus kaustophilus, averaging about 862 nucleotides in size. These coding sequences were determined to make up about 86% of the chromosome (5).

Cell structure and metabolism

The bacterium is thermophilic, which means it is capable of surviving in high temperatures. It has one membrane, flagella and is rod-shaped. The bacterium is also an aerobic endosporing-forming Gram-positive microbe (5). When grown in colonies, the cells are convex and transparent. They produce spores that are oval to cylindrical and may swell the sporangium (3).



Application to Biotechnology

In recent studies, it was discovered that a strain of isolated bacteria from a culture of Geobacillus strain T1 was able to produce the enzyme lipase (4). This purified sample of bacteria were aerobic, Gram-positive, endospore-forming, and rod-shaped. Lipase is a vital enzyme that is used frequently in our bodies. Lipases “catalyze the hydrolysis of long chain triglyceride into diacylglyceride, monoglyceride, glycerol and free fatty acids” (4). They also aid in the reverse reaction of hydrolysis to produce esters from alcohol or fatty acids. What is unique in this finding is that the lipase is thermostable, which means that it can withstand high temperatures. This is beneficial in industries and diagnostic equipment since the enzyme will not denature under high temperature. Lipase also contributes in the flavoring of diary products and as medicine to help digest food. With its thermostable characteristic, it can create a wider range of products (4). Unfortunately, Geobacillus strain T1 will not have a major role in the production of lipase anywhere in the near future. Not only does it have a low yield of the enzyme, but the equipment required for its high temperature fermentation is also expensive (4).

Current Research

1. Detecting Antibiotic Residues: An assay is being developed with Geobacillus kaustophilus as the central element in order to detect the presence of antibiotics. In this assay, the concentration of antibiotics in food or other contaminated substances can be identified within 1.5 to 4.5 hours. What is unique about this technique of using Geobacillus kaustophilus is that it can detect concentrations of antibiotics up to the maximum level allowed in food. (7) 2. Thermoadaptation trait revealed by the genome sequence of thermophilic Geobacillus kaustophilus: The genone sequence of Geobacillus genus were compared to that of mesophiles, which are organisms that grow best in moderate temperature. After comparing the results, there were some amino acids substitutions in Geobacillus that could possibly be responsible for the thermophilic nature of Geobacillus species. This was the first time that these differences in genome structure were founded. (5) 3. Lipase from Geobacillus sp. strain T1: A pure strain of Geobacillus sp. Strain T1 bacteria was isolated from Palm Oil Mill Effluent and was discovered to be able to produce thermally-stable lipase T1. Lipase is a vital part of metabolism in organisms. It is an enzyme that hydrolyzes fat to make free fatty acids. The development of this discovery could lead to new medicines for digestive problems and a widening of flavors for dairy products. However, the study is still a work in progress since the lipase yield is low and the high temperature equipment is expensive. (4)

References

1. EMBL-EBI. <http://www.ebi.ac.uk/2can/genomes/bacteria/Geobacillus_kaustophilus.html>

2. NCBI. <Http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=1462&lvl=3&p=mapview&p=has_linkout&p=blast_url&p=genome_blast&lin=f&keep=1&srchmode=1&unlock>

3. Priest,F.G. “Systematics and ecology of Bacillus.” In Sonenshein,A.L., Hoch,J.A. and Losick,R. (eds), Bacillus subtilis and Other Gram-positive Bacteria. (1993): 3–16.

4. Rahman, Raja Noor Zaliha Abd., Selangor, Salleh, Abu Bakar Basri, Mahiran, Chor, Selangor, Thean. “Lipase from Geobacillus sp. Strain T1.”(2006). < http://www.freepatentsonline.com/20060024789.html>.

5. Takami, H., Takaki, Y., Chee, G., Nishi, S., Shimamura,S., Suzuki, H., Matsui, S., Uchiyama, I. “Thermoadaptation trait revealed by the genome sequence of thermophilic Geobacillus kaustophilus”. Nucleic Acids Research 32.21(2004): 6292-6303. <http://nar.oxfordjournals.org/cgi/content/abstract/32/21/6292>.

6. T. N. Nazina, T. P. Tourova, A. B. Poltaraus, E. V. Novikova, A. A. Grigoryan, A. E. Ivanova, A. M. Lysenko, V. V. Petrunyaka, G. A. Osipov, S. S. Belyaev1 and M. V. Ivanov. “Taxonomic Study of aerobic Thermophilic Bacilli.” International Journal of Systematic and Evolutionary Microbiology 51(2001): 433-446.

7. Uson, Santiago, Tomas, Rafael, Perez, David. “Method of Detecting Antibiotic Residues and other Microbial Compounds.” World Intellectual Property Organization. (2006). <http://www.wipo.int/pctdb/en/wo.jsp?wo=2006058936>.



Edited by Tony Le

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