What are alkaliphiles?
Alkaliphiles are a class of extremophilic microbes capable of survival in alkaline ( pH roughly 8.5–11) environments, growing optimally around a pH of 10.
Where are haloalkaliphiles found?
Alkaliphilic microorganisms can be found even in the environment where overall pH may not be alkaline. Haloalkaliphiles have been mainly found in extreme alkaline and saline environments such as Rift valley lakes of East Africa and Western Soda lakes of the United States (Horikoshi, 1999).
What is the optimum pH for alkaliphiles?
Alkaliphiles are microbes that grow well between pH 8 and 10.5. Extreme alkaliphiles show optimum growth pH 10 or higher. Alkaliphiles are usually found in soda lakes and high carbonate soils and sometimes even in garden soils. Agrobacterium is an extreme alkaliphile that grows optimally at pH 12.
What are the two types of alkaline environments?
15.2. Alkaline Environments Alkaline environments can be placed into two categories depending upon the nature of the process of generation of alkalinity, viz., stable alkaline environments and transient alkaline environments. Stable alkaline environments are caused by combination of climatic, geological, and geographical conditions.
How are alkaliphiles adapted to their environment?
Alkaliphiles are organisms that grow at high pH values. They adapt themselves by maintaining cytoplasmic pH homeostasis and uptake of H+ using electrogenic, secondary cation/proton antiporters.
How do alkaliphiles maintain pH?
Alkaliphilic bacteria compensate for reversal of the pH gradient by having a high membrane potential or by coupling Na+ expulsion to electron transport for pH homeostasis and energy transduction.
How is Alkaliphilic enzymes used in industry?
Other alkaline enzymes, e.g. alkaline cellulases, alkaline amylases, and alkaline lipases, are also adjuncts to detergents for improving cleaning efficiency. Alkaline enzymes often show activities in a broad pH range, thermostability, and tolerance to oxidants compared to neutral enzymes.
Where is an alkaline environment?
An alkaline environment is a setting that is strongly basic or contains alkali components. This usually refers to an environment with a pH value higher than 7.0, since a pH below 7.0 is considered acidic.
What are examples of alkaliphiles?
Examples. Examples of alkaliphiles include Halorhodospira halochloris, Natronomonas pharaonis, and Thiohalospira alkaliphila.
What does alkaliphiles mean?
The term “alkaliphile” is used for microorganisms that grow optimally or very well at pH values above 9 but cannot grow or grow only slowly at the near-neutral pH value of 6.5. Alkaliphiles include prokaryotes, eukaryotes, and archaea.
Can bacteria grow in alkaline water?
The capacity of bacteria to survive and grow at alkaline pH values is of widespread importance in the epidemiology of pathogenic bacteria, in remediation and industrial settings, as well as in marine, plant-associated and extremely alkaline ecological niches.
What kind of medium is used for isolation of alkaliphiles?
alkaline mediaIsolation of alkaliphilic microorganisms must be carried out in alkaline media containing sodium car- bonate, sodium bicarbonate, potassium carbonate or sometimes sodium borate.
Why for instance are alkaliphiles able to survive at high pH?
Why, for instance are alkaliphiles able to survive at high pHs when neutrophiles cannot? The cells won't be far enough apart to grow individual colonies.
Are vaginas acidic?
The vagina's pH level is about 3.8 to 4.5, which means it's on the acidic side. Its acidity slightly decreases as you get older, with its pH level rising closer to 5.
Is milk an alkaline or acid?
Milk is presumed to be alkaline, although it actually comes in at between pH 6.5 and 6.7 which makes it slightly acidic Therefore, it can neutralize stomach acid to some degree but not as much as you might assume.
Is honey an alkaline?
One of those chemical characteristics is the pH of honey. Outside of the body, before ingestion and digestion, honey is acidic. Once metabolized, honey is considered alkaline.
Why for instance are alkaliphiles able to survive at high pH?
Why, for instance are alkaliphiles able to survive at high pHs when neutrophiles cannot? The cells won't be far enough apart to grow individual colonies.
What about pH discuss the adaptation of acidophiles and alkaliphiles?
Acidophiles grow optimally at a pH near 3.0. Alkaliphiles are organisms that grow optimally between a pH of 8 and 10.5. Extreme acidophiles and alkaliphiles grow slowly or not at all near neutral pH. Microorganisms grow best at their optimum growth pH.
What pH do halophiles grow in?
Growth under extremes of pH. The growth optimum for the Halobacteriaceae is around pH 7 2, 22, 23. Specifically, for the organisms used in this study, it is pH 7.4, 7.5, and 7.2 for Halorubrum lacusprofundi, Haloferax volcanii, and Halobacterium sp.
How do acidophiles survive?
Acidophiles thrive under highly acidic conditions such as marine volcanic vents, and acidic sulfur springs, acid rock drainage (ARD) and acid mine drainage. These microorganisms have adapted themselves by maintaining their cellular pH neutral and also acquire resistance towards metals [24,63,64].
Where is catalase produced?
A catalase peroxidase producing microorganism Streptomyces sp. IMSNU-1 has been isolated from Kwanak Mountain, Seoul, Korea ( Youn et al., 1995 ). An alkalothermophilic bacterium having a wide variety of characteristics belonging to Bacillus sp. from wastewater of the textile industry has been isolated on nutrient broth prepared in sodium carbonate and sodium bicarbonate buffer (50 mM, pH 10.0) in a rotary shaker at 60 °C ( Gudelj et al., 2001 ). Another catalase-producing bacterial strain from Pseudomonad EF group 70B was isolated from pulp processing water ( Kuusk et al., 2001 ). A rod-shaped catalase-producing bacterium Comamonas terrigena N3H has also been isolated from a contaminated soil sample in Slovakia ( Zamocky et al., 2001 ).
What microorganisms produce catalase?
Catalase-producing microorganisms have been isolated from fish processing plants. A psychrotolerant bacterium, Vibrio rumoiensis S-1 T with extraordinarily high catalase activity, was isolated from a fish processing industrial drain ( Yumoto et al., 1998). Another novel catalase and oxidase-positive, facultatively aerobic alkaliphile Exiguobacterium oxidotolerans able to grow at a pH of 7.0–10.0 and in 0–12% NaCl was also reported from a fish processing plant effluent in Hokkaido, Japan ( Yumoto et al., 2004 ). A number of extremophilic catalase-positive microorganisms isolated from extreme environments around the world are listed in Table 2. A novel alkali and thermostable catalase-producing bacteria Thermus brockianus was reportedly found in hot spring with an average temperature of 70 °C and pH of 7.0 at Yellowstone National Park, USA ( Thompson et al., 2003 ).
Does rice have arsenic?
Some plants also have proteins related to Acr3 that confer arsenic tolerance. For example, an Acr3 orthologue was recently identified in the vacuole of the brake fern Pteris vittata and is responsible for arsenic tolerance in the plant ( Indriolo, Na, Ellis, Salt, & Banks, 2010 ). In contrast, rice ( Oryza sativa) does not have Acr3, yet arsenic in the rice grain is a serious health hazard ( Zhao, McGrath, & Meharg, 2010 ). To attempt to mitigate this problem, yeast ScAcr3 was expressed in rice, with the result that the arsenic content in the grain was reduced ( Duan, Kamiya, Ishikawa, Arao, & Fujiwara, 2012 ).
What is the pH range of alkaliphiles?
The term "alkaliphile" is used for microorganisms that grow optimally or very well at pH values above 9 but cannot grow or grow only slowly at the near-neutral pH value of 6.5.
What is an alkaliphile?
The term "alkaliphile" is used for microorganisms that grow optimally or very well at pH values above 9 but cannot grow or grow only slowly at the near-neutral pH value of 6.5. Alkaliphiles include prokaryotes, eukaryotes, and archaea.
What are alkaliphiles in laundry detergent?
The current proportion of total world enzyme production destined for the laundry detergent market exceeds 60%.
Can alkali treated wood pulp be bleached?
It has also been reported that alkali-treated wood pulp could be biologically bleached by xylanases produced by alkaliphiles.
Can alkaliphiles be isolated?
Many different taxa are represented among the alkaliphiles, and some of these have been proposed as new taxa. Alkaliphiles can be isolated from normal environments such as garden soil, although viable counts of alkaliphiles are higher in samples from alkaline environments.
Where are alkaliphiles found?
Alkaliphilic microorganisms can be found even in the environment where overall pH may not be alkaline. Haloalkaliphiles have been mainly found in extreme alkaline and saline environments such as Rift valley lakes of East Africa and Western Soda lakes of the United States ( Horikoshi, 1999 ). Professor Horikoshi extensively studied alkaliphiles and contributed in a major extent in developing interest in alkaliphiles. Since then, alkaliphiles have gained more attention.
How are alkaliphiles distributed?
Alkaliphiles are not confined to a single group or to a defined set of phylogenetic lineages, but they are widely distributed in various evolutionary branches ( Jones et al., 1994 ). Earlier, many of the diversity studies of alkaliphiles have been done by traditional culturing and taxonomic procedures. Cultured microorganisms represent only a minor component in the existing diversity of Soda Lakes because most of the microbial population is difficult to culture. Molecular techniques have been found very effective in exploring microbial diversity and the structure of the microbial communities. Recovery of the 16 S rRNA genes directly from environmental samples provides a mean of investigating microbial populations of any ecosystem ( Jones et al., 1998 ). Jones et al., 1994, Jones et al., 1998 and Duckworth et al. (1996) discussed at length about systematic studies and phylogenetic diversity of Soda Lake alkaliphiles. The study of Duckworth et al. (1996) included phylogenetic analyses of more than 40 alkaliphilic bacteria and archaea from a range of East African Soda lake habitats. 16 S rRNA genes from a range of aerobic, chemoorganotrophic alkaliphilic bacteria and archaea isolated from East African Soda Lake habitats have been sequenced. Phylogenetic analyses of the isolates revealed that the Gram-negative alkaliphiles were found to be confined to the γ3 subdivision of the Proteobacteria with many isolates related to Halomonas and Deleya group. Gram-negative alkaliphiles were found to be most closely related to Enterobacteria / Aeromonas / Vibrio part of the γ 3 subdivision and Pseudomonas region of the γ 3 subdivision. Gram-positive alkaliphiles were found to be present in both high G+C and low G+C divisions with many isolates related to Bacillus and Arthrobacter. Alkaliphilic haloarchaea were closely related to the members of genera Natronococcus and Natronobacterium. An anaerobic thermophilic isolate has been assigned to a new genus within Thermotogales which is closely related to the genus Fervidobacterium.
Why are alkaliphiles so active?
The alkaliphiles perform their metabolic reactions at such high pH due to the activity of these extremozymes. If we initiate our discussion from the alkaline protease from Bacillus, reported by Horikoshi (1971), remarkable activity was recorded at 11.5 pH which was active up to 13 pH with 3/4 of its activity that was completely differ from the normal proteases. The molecular level investigation on such alkaliphilic strains for their genes corresponding to proteases revealed these alkaline proteases are very diverse from the other subtilisins. They have the unique sequences of amino acids that make them more resistant, hence they are categorized as oxidatively stable ( Saeki et al., 2000 ). The alkaline proteases explored at genetic and proteomic level and have been showed high similarity and they are also resistant against detergents and oxidizing agents ( Deng et al., 2010 ). The properties of such stable alkaline proteases makes them more promising candidate for the industries related to cleaning such as laundry and the pharmaceuticals ( Joo et al., 2003, Ibrahim et al., 2015 ).
How does bioenergetics help with alkaliphiles?
Bioenergetics plays an important role in the survival at high pH because in the alkaline conditions energy demands for cell increases due to the pH homeostasis and the production of ATP along with to cope up with the other side effects of high pH (such as stressed cell wall). The principal mechanism behind the pH homeostasis in alkaliphiles is the active intrusion of H+ ions through Na + /H + antiporters. These antiporters are membrane proteins and act as secondary active transporters (energized by the transmembrane electrical potential: ΔΨ). Transmembrane electrical potential is the difference in the inner and outer layer of membrane. This energy difference helps to drive the proton ions toward cytoplasm as the exchange of sodium ion outside the cell. This electric potential is generated by the primary ion pumps and other biochemical reactions related to ATP metabolism.
What is the best pH for alkaliphiles?
Alkaliphiles are the microorganisms that grow optimally at pH 9 and above but are unable to grow or grow very slowly at around neutral pH, i.e., pH 7.0–6.5 ( Horikoshi, 1999 ). Alkaliphiles are further divided into facultative alkaliphiles, obligate alkaliphiles, and alkalitolerant microorganisms. Facultative alkaliphiles grows well at neutral pH, while obligate alkaliphiles grows above pH 9 and unable to grow at neutral pH. Alkalitolerant microorganisms grow well up to pH 10 but exhibit rapid growth below pH 9.5. In addition to these categories, many alkaliphiles are adapted to high salt concentrations; they are called haloalkaliphiles. They require both high alkaline pH (>9) and high salinity (up to 33% w/v NaCl) for growth.
What are the two types of alkaline environments?
Alkaline environments can be placed into two categories depending upon the nature of the process of generation of alkalinity, viz., stable alkaline environments and transient alkaline environments. Stable alkaline environments are caused by combination of climatic, geological, and geographical conditions. Soda lakes and deserts represent the most stable, naturally occurring alkaline environments. Contrary to this, transient alkalinity in microhabitats like soil arises due to soil microbial processes like ammonification and sulfate reduction. These processes rarely lead to stable pH > 10. Human industrial activities like cement manufacturing [Ca (OH)2 ], mining operation, paper and pulp production (NaOH), electroplating, hide processing, and food processing also generate alkaline environments because of the chemistry of components used in that process ( Grant, 2006 ). Transient alkaline environments also include formation of alkaline hot springs in volcanic areas having pH 9.5 ( Hensel et al., 1997) where alkalinity might be generated by decomposition of silicates. In such environments, maintenance of stable alkaline pH is limited. Such transient alkaline environments are very less studied, and thus no information is available about alkaliphilic inhabitants present in such environments. In contrast, a far more diverse microbial alkaliphilic population is found in stable naturally occurring alkaline environments. There are two kinds of stable alkaline environments, viz., low Ca 2+ environments including soda lakes and deserts and high Ca 2+ environments including groundwater bearing high CaOH ( Ulukanli and Digrak, 2002 ).
Where are the Wadi Natrun lakes located?
The Wadi Natrun lakes are situated in Egypt about 100 km North West of the Cairo. The valley contains number of shallow lakes which has inflow by underground seepage from Nile River, and they have become hypersaline due to evaporative concentration. Imhoff et al. (1979) studied in detail Wadi Natrun Lakes. Wadi Natrun lakes, i.e., Lake Gabara, Muluk, Hamora, Zugm, Gaar, Rizunia are populated by alkaliphilic and halophilic microorganisms. The lakes reported the total dissolved salt concentration between 9.0%–39% (w/v). pH of the lakes is around 11 with sodium and potassium as major cations. Concentration of magnesium and calcium is very low. The display of different colors of green, red, and purple according to the seasonal bloom of Cyanobacteria, halophilic archaea, and purple bacteria is observed in these lakes. Lake Gabara having salt concentration 9% (w/v) was populated by Spirulina and other Cyanobacteria. The bottom surface harbored an active community of sulfate-reducing bacteria (SRBs). A large population of Chromatium like bacteria observed close to the sediments of Lake Gabara. Lake Muluk having 15% (w/v) salts contained Cyanobacterial mat and halophilic anoxygenic phototrophs like Halorhodospira halochloris and Halorhodospira halophila. The water of the Hamara having the salt concentration 23.8% (w/v) was light red due to the presence of haloalkaliphilic archaea. Phototrophic sulfur bacteria were also present in the mud. Most saline lakes, Lake Gaar having the salt concentration 37.4% (w/v), Rhizunia (38% w/v), and Zugm (39.4% w/v), were populated by alkaliphilic archaea, phototrophic purple bacteria, and few Cyanobacteria ( Oren, 2002 ). Study of Imhoff and Trüper (1981) and Imhoff (1988) revealed a substantial number of novel species of microorganisms from Wadi Natrun Lakes.
Which adaptation is shared by all alkaliphiles?
The intracellular pH homeostasis is a vital adaptation shared by all alkaliphiles as all alkaliphiles maintain lower cytoplasmic pH than its external environment.
Which two types of environment provide habitats for the most xerophilic organisms?
Two major types of the environment provide habitats for the most xerophilic organisms, namely foods preserved by some form of dehydration or organic solute-promoted lowering of a w and saline lakes, where low a w values are a consequence of inorganic ions.
What are extremophiles?
Extremophiles are living organisms with the ability to survive and thrive in extreme environments as a result of different physiological and molecular adaptations.
Why are radiophiles limited?
Studies on radiophiles are quite limited as they are to be isolated from extreme environments like outer space of other planets.
What temperature do thermophiles grow?
Typically, a thermophile shows maximum growth rates at temperatures above 45°C. There are many examples of the environment with extreme temperatures.
Why do halophiles have to increase their osmotic activity?
In order to avoid excessive water loss under high salt conditions, halophiles have employed two distinct strategies to increase the osmotic activity of their cytoplasm with the external environment, either producing compatible organic solutes or accumulating large salt concentrations in their cytoplasm to reach an equilibrium state in which the overall salt concentration within cells correlates that of the environment.
What are the characteristics of an extremophile?
Characteristics of extremophiles. Extremophiles are characterized by the ability to thrive in extreme environments which results from different forms of physiological and molecular adaptations. Extremophiles are mostly prokaryotes with the nuclear material in the cytoplasm and unicellular eukaryotes.
Why do alkaliphiles pump protons across their cell membranes?
Because alkaline conditions damage cells, so-called alkaliphiles pump protons across their cell membranes to reduce the pH inside their cells. There are places on Mars, like Gusev Crater, which resemble soda lakes on Earth, according to an analysis of minerals by NASA’s Spirit rover.
Which environment has the highest pH?
The most alkaline environments in the world are soda lakes, which can have a pH as high as 12, akin to ammonia. A number of microbes enjoy those caustic conditions, including Natronomonas pharaonis, which was first isolated from soda lakes in Egypt and Kenya in the 1980s.
How far down can microorganisms be found?
Communities of microorganisms have been found hunkered down in groundwater as far as 5 km below the surface of the land. Scientists think life exists even further down – to the point where the subsurface heat becomes unbearable for life. Even the deepest part of the ocean, the Mariana Trench, which plunges 11 km below the surface ...
Where are living cells found?
Recently, living cells – many of which are Archaea from the Pyrococcus and Thermococcus genera – were found in a mud core taken from 1.6 km below the sea floor off the coast of Newfoundland. Though they represent the deepest life ever discovered beneath the sea floor, microbes of various kinds have been discovered at even greater depths under the continents. Communities of microorganisms have been found hunkered down in groundwater as far as 5 km below the surface of the land. Scientists think life exists even further down – to the point where the subsurface heat becomes unbearable for life.
What was the first place to find alkaline rocks on Mars?
Life 25 June 2008. By Anna Davison. The Spirit rover found alkaline rocks in Gusev Crater, the first time such rocks were seen on Mars. (Image: NASA) The Atacama Desert in Chile is the driest place on Earth – too dry in some places to support any life. (Image: Chris McKay)
What is the pH of a geyser?
The most extreme acidophiles known are microbes of the genus Picrophilus. They thrive at a pH of 0.7, and can grow down to a drain-clearing pH of 0.
Where are acidophiles found?
Acidophiles are found in volcanic areas, hydrothermal sources, deep-sea vents, geysers and sulfuric pools or in the stomachs of animals. These microorganisms are generally used in food preservation such as pickling.
What are Alkaliphiles?
Alkaliphiles are microbes that grow well between pH 8 and 10.5. Extreme alkaliphiles show optimum growth pH 10 or higher. Alkaliphiles are usually found in soda lakes and high carbonate soils and sometimes even in garden soils. Agrobacterium is an extreme alkaliphile that grows optimally at pH 12.
What are Neutrophiles?
Neutrophiles are microorganisms that prefer a pH around 6.5 to 7.5 in order to grow optimally. Most bacteria, including human pathogenic bacteria, are neutrophiles. In addition to bacteria, there are neutrophilic microalgae, phytoplankton, and yeasts. These microbes prefer neutral environments. Therefore, they are commonly found in nature.
What are the Similarities Between Acidophiles Neutrophiles and Alkaliphiles?
Acidophiles, neutrophiles and alkaliphiles are three groups of microorganisms categorized based on the basis of pH requirement.
What are the three groups of microorganisms that live in acidic environments?
Microorganisms live and thrive within specific pH levels. Based on the optimum growth pH, there are three groups of microorganisms. Acidophiles thrive in acidic environments while neutrophiles thrive in neutral environments and alkaliphiles thrive in alkaline environments. Thus, this is the key difference between acidophiles neutrophiles and alkaliphil es.
What are the three major groups of microorganisms?
Based on the optimum growth pH, we can categorize microorganisms into three major groups as acidophiles neutrophiles and alkaliphiles. Acidophiles prefer pH near 3; neutrophiles prefer pH near 7; alkaliphiles grow well between pH 8 and 10.5. When the pH is not in the required growth pH range, they show a slow growth or they don’t grow.
What is the difference between acidophiles and alkaliphiles?
Difference Between Acidophiles Neutrophiles and Alkaliphiles. The key difference between acidophiles neutrophiles and alkaliphil es is that acidophiles are microorganisms that grow at a pH near to 3 while neutrophiles are microorganisms that grow at a pH near to neutral or 7 and alkaliphiles are microorganisms that grow well between the pH ...
