Geobacillus stearothermophilus: Difference between revisions

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==Application to Biotechnology==
==Application to Biotechnology==


A strain of Geobacillus stearothermophilus isolated from Mae’en hot springs in Jordan was characterized as being one of the first α-amylase producing thermophilic bacteria.  α-Amylase, an enzyme used in the production process of sweeteners from starch, is of major industrial interest.  Some requirements of the enzyme are that it must withstand high processing temperatures during the conversion from starch to sweetener.  This necessitates the use of thermo-stable α-amylase.  Geobacillus stearothermophilus JT2 was isolated and grown at high temperatures (55°C) with starch as a carbon source.  The bacteria grew up to high densities supporting that the thermophilic bacteria contains resident enzymes more resistant to degradation at high temperatures. (6)  This is an area of ongoing research as more researchers study the industrial applications of thermophilic bacteria.
A strain of Geobacillus stearothermophilus isolated from Mae’en hot springs in Jordan was characterized as being one of the first α-amylase producing thermophilic bacteria.  α-Amylase, an enzyme used in the production process of sweeteners from starch, is of major industrial interest.  Some industrial requirements of the enzyme are that it must withstand high processing temperatures during the conversion from starch to sweetener.  This necessitates the use of thermo-stable α-amylase.  Geobacillus stearothermophilus JT2 was isolated and grown at high temperatures (55°C) with starch as a carbon source.  The bacteria grew up to high densities supporting that the thermophilic bacteria contains resident enzymes more resistant to degradation at high temperatures. (6)  This is an area of ongoing research as more studies are conducted on the industrial applications of thermophilic bacteria.


The Biotechnologies industry depends greatly upon its ability to create sterile environments in which to conduct aseptic processes.  Specialized equipment has been developed to sterilize equipment and areas of interest with the use of high temperatures and steam.  The sterilization processes for the biotech industry is highly tested to ensure the absolute of “sterility”.  Geobacillus stearothermophilis spores are widely used to test the lethality of an autoclave or other equipment performing a sterilization process. (8)  The thermophilic bacteria Geobacillus stearothermophilis are highly resistant to heat and are therefore used in equipment validation studies to prove that sterilization took place. The spores used in these studies are called Biological Indicators (BI’s) and offer biological evidence for a sterilization process.
The Biotechnologies industry depends greatly upon its ability to create sterile environments in which to conduct aseptic processes.  Specialized equipment has been developed to sterilize equipment and areas of interest with the use of high temperatures and steam.  The sterilization processes for the biotech industry is highly tested to ensure the absolute of “sterility”.  Geobacillus stearothermophilis spores are widely used to test the lethality of an autoclave or other equipment performing a sterilization process. (8)  The thermophilic bacteria Geobacillus stearothermophilis are highly resistant to heat and are therefore used in equipment validation studies to prove that sterilization took place. The spores used in these studies are called Biological Indicators (BI’s) and offer biological evidence for a sterilization process.
==Current Research==
==Current Research==


A recent study evaluated surface complexation models (SCM’s) in quantifying metal ion adsorption by thermphilic bacteria.  Of the microorganisms studied Geobacillus stearothermophilus was observed for its heat tolerance and anaerobic metabolism.
A recent study evaluated surface complexation models (SCM’s) in quantifying metal ion adsorption by thermphilic bacteria.  Of the microorganisms studied Geobacillus stearothermophilus was observed for its heat tolerance and anaerobic metabolism.

Revision as of 17:28, 29 August 2007

A Microbial Biorealm page on the genus Geobacillus stearothermophilus


Classification

Higher order taxa

Bacteria (Domain); Firmicutes (Phylum); Bacilli (Class); Bacillales (Order); Bacillaceae (Family); Geobacillus (Genus) (1)

Genus

Geobacillus stearothermophilus

Description and significance

Geobacillus stearothermophilus is a gram positive thermophilic bacteria characterized by a inner cell membrane and a thick cell wall. G. stearothermophilus is a rod shaped anaerob found in thermophilic habitats. Many heat stable enzymes like xylanase for pulp treatment and thermolysin-like protease for production of artificial aspartame have been isolated from this thermophilic bacteria. (2) Geobacillus stearothermophilus strain 10, is an isolated strain that was found in a hot spring in Yellowstone National Park and has been used in comparative analysis of thermophiles and mesophiles. Geobacillus stearothermophilus is constantly used in the biotech industry to test the success of sterilization cycles of equipment. Due to the bacteria’s high resistance to heat, it is a suitable Biological Indicator of microbe life after a sterilization cycle.

Strain Geobacillus stearothermophilus JT2 when grown on blood agar plates are observed to have an ellipsoidal shape and adhere to each other to form longitudinal chains containing two or more cells. (6) This strain is observed to be highly motile and produces a highly temperature stable enzyme α-amylase (read more below). (6)

G. stearothermophilus contain endospores which are a highly resistant dormant form of the bacteria. The bacteria produce spores under harsh conditions when nutrient levels are low. The spore core is dehydrated (10-25% water content) making it very resistant to heat and chemicals. (9) To protect the DNA Ca2+ dipcolinic acid complex and small acid-soluble proteins (SASP) bind to the spore DNA and increase the spores’ resistance to desiccation. The outside of the spore is comprised of loosely cross linked peptidoglycan which prevents hydration and acts as a permeability barrier to chemicals such as lysozyme. (9)

Genome structure

Genome structure for this bacteria is still being determined. This is being pursued at Tarbiat Maderes University in Tehran, Iran. (7)

Recent research conducted at Germany’s Humbolt University, has identified an ATP-binding cassette transporter in the genome of G. stearothermphilus srain DSMZ 13240. (10) Researchers isolated a gene cluster of the Gram-positive bacteria that encoded for a “high-affinity” arginine ABC-transporter complex. The ABC-transporter complex seems to be more reliable for predicting substrate specificity due to the use of a highly cognate binding protein rather than the hydrophobic subunits of the ABC-transporter. (10).

A plasmid was isolated in Geobacillus stearothermophilus (strain TK05), named Plasmid pSTK1. The plasmid is 1,883 nucleotides in lenth and contains 44% guanine cytosine content and 56% adenosine thymine content. The plasmid carries three genes of which code for three different proteins. (3) .

Cell structure and metabolism

L. jensenii, like other members of the Lactobacillus, are rod-shaped, anaerobic Gram-positive microorganisms. Ideal growth conditions require the presence of folic acid, vitamin B12, nictonic acid, and calcium pantothenate at 45ºC. It can be differentiated from other species because of the following characteristics: hydrolysis of arginine, production of D-lactate (only), and fermentation of galactose, salicin, esculin, maltose amygdalin, sucrose, ribose, and cellobiose, but not of lactose, melexitose, mannitol, sorbitol, arabinose, and xylose (10).

As an anaerobe and the member of Lactobacillus - bacteria known for acids production, L. jensenii is responsible for producing acid in the vagina by anaerobic metabolism of glycogen. The glycogen is deposited in the vaginal epithelium cells when there is a high level of estrogen, specifically during menstruation period. The vaginal flora and the surrounding epithelial cells metabolize the glycogen into acetic and lactic acid so that the vaginal pH becomes about 4. The strong concentration of the acidic environment help protect the vagina from harmful pathogens in the environment (1).

Ecology

Pathology

Application to Biotechnology

A strain of Geobacillus stearothermophilus isolated from Mae’en hot springs in Jordan was characterized as being one of the first α-amylase producing thermophilic bacteria. α-Amylase, an enzyme used in the production process of sweeteners from starch, is of major industrial interest. Some industrial requirements of the enzyme are that it must withstand high processing temperatures during the conversion from starch to sweetener. This necessitates the use of thermo-stable α-amylase. Geobacillus stearothermophilus JT2 was isolated and grown at high temperatures (55°C) with starch as a carbon source. The bacteria grew up to high densities supporting that the thermophilic bacteria contains resident enzymes more resistant to degradation at high temperatures. (6) This is an area of ongoing research as more studies are conducted on the industrial applications of thermophilic bacteria.

The Biotechnologies industry depends greatly upon its ability to create sterile environments in which to conduct aseptic processes. Specialized equipment has been developed to sterilize equipment and areas of interest with the use of high temperatures and steam. The sterilization processes for the biotech industry is highly tested to ensure the absolute of “sterility”. Geobacillus stearothermophilis spores are widely used to test the lethality of an autoclave or other equipment performing a sterilization process. (8) The thermophilic bacteria Geobacillus stearothermophilis are highly resistant to heat and are therefore used in equipment validation studies to prove that sterilization took place. The spores used in these studies are called Biological Indicators (BI’s) and offer biological evidence for a sterilization process.

Current Research

A recent study evaluated surface complexation models (SCM’s) in quantifying metal ion adsorption by thermphilic bacteria. Of the microorganisms studied Geobacillus stearothermophilus was observed for its heat tolerance and anaerobic metabolism.