Information AboutPsychrophilic |
| CATEGORIES ABOUT PSYCHROPHILE | |
| microbial growth and nutrition | |
| extremophiles | |
|
Psychrophiles utilize a wide variety of metabolic pathways, including Photosynthesis , chemoautotrophy (also sometimes known as lithotrophy), and Heterotrophy , and form robust, diverse communities. Most psychrophiles are Bacteria or Archaea , and psychrophily is present in widely diverse microbial lineages within those broad groups. Additionally, recent research has discovered novel groups of psychrophile fungi living in oxygen-poor areas under alpine snowfields. Psychrophiles are characterized by lipid cell membranes chemically resistant to the stiffening caused by extreme cold, and often create protein 'antifreezes' to keep their internal space liquid and protect their DNA even in temperatures below water's freezing point. __NOTOC__ TYPES OF PSYCHROPHILES There are generally considered to be two groups of psychrophiles: ''"obligate"'' psychrophiles, and a second group, the ''"facultative psychrotrophs"'', that are sometimes referred to as ''psychrotrophs'' by Food Microbiologist s. Obligate psychrophiles Obligate psychrophiles are those organisms having a growth temperature optimum of 15°C or lower and cannot grow in a climate beyond a maximum temperature of 20°C. They are largely found in icy places (such as in Antarctica ) or at the freezing bottom of the Ocean floor. This separation is becoming more difficult as more organisms with a fairly large growth temperature range are discovered. Facultative psychrophiles Facultative psychrophiles can grow at 0°C up through approximately 40°C, and exist in much larger numbers than obligate psychrophiles. They are generally not able to grow much below 0°C, though they may maintain basic functioning. They have evolved to tolerate cold, but they are not as physiologically specialized as obligate psychrophiles and are usually not found in the very coldest of environments. They are of particular significance to food microbiologists as they can grow in refrigerated environments and thereby cause food spoilage. SEE ALSO EXTERNAL LINKS |
|
|