For exemple tannase:
A novel tannase from the xerophilic fungus Aspergillus niger GH1
Mata-Gómez Marco, Luis V Rodríguez, Erika L Ramos, Jacqueline Renovato, Mario A Cruz-Hernández, Raúl Rodríguez, Juan Contreras, Cristóbal N Aguilar
J Microbiol Biotechnol 1, 1-10, 2009
Xerophilic fungi : are yeasts and molds that are capable of growth at or below a water activity (aw) of 0.85. These microorganisms have developed physiological mechanisms that enable their biochemical pathways to function in environments where little water is available.
External conditions of low aw are sensed by membrane osmosensors, and xerophiles then accumulate glycerol as a compatible solute to balance the internal and external osmotic pressure. They also modify their membranes to retain this glycerol within the cell. As a group, xerophiles are extremely important in the spoilage of many processed foods and stored commodities, and in indoor environments.
Moderate xerophiles include species within Aspergillus, Penicillium and Eurotium. Extreme xerophiles compete poorly at high aw, because they require decreased aw for growth. Some xerophiles have a preference for salt or sugar substrates, whereas other species can be isolated from both jam and salterns. Xerophiles are widely spread on the fungal tree of life.
- Xerophiles have requirement for reduced water activity; fungi are the most successful xerophilic organisms, and the most extreme xerophiles are found among fungi.
- Compatible solutes are accumulated intracellularly to maintain the osmotic balance in response to decreased water availability.
- Glycerol is the primary compatible solute among xerophilic fungi.
- Membrane composition plays an important role in retaining glycerol within the cells of xerophiles.
- Moderate xerophiles of the genera Aspergillus, Eurotium and Penicillium are economically important spoilage organisms.
- Some xerophiles are isolated from both high‐salt and high‐sugar environments; others have a preference for either salt or sugar.
- Xerophiles can cause spoilage of food and feed: stored commodities, sugary products and salted foods.
- Xerophilic species are widely spread on the fungal tree of life.
Fungi have some common characteristics of osmotolerance, for instance they all employ the compatible solutes strategy: they balance the osmotic pressure of the surroundings by accumulating small organic molecules (compatible solutes), most commonly glycerol, and maintain low intracellular concentrations of salt (such as toxic Na+ ions )
The ability of fungi to tolerate high or low temperatures suggests that there are species which can actively live and tolerate such extremes and use different mechanisms to survive such stress. Enzymes produced by both thermophiles and psychrophiles have received particular attention for biotechnological and pharmaceutical reasons.
Xerophilic fungi protein has a thermal stability and thier enzymes are not destroyed or breaked by high degrees of temperature.
Xerophilic fungi are yeast and moulds that are capable of growth at or below a water activity of 0.85. These microorganisms have developed physiological mechanisms that enable their biochemical pathways to function in environments where little water is available. External conditions of low water activity are sensed by membrane osmosensors, and xerophiles then accumulate glycerol as a compatible solute to balance the internal and external osmotic pressure. They also modify their membranes to retain this glycerol within the cell.
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