Lecture 2: Environmental Microbiology PDF

Lecture 2 Dr. Eman El Gebaly  Not do a lot, but what do, do well Microbes have Extremophiles small genomes Having optimal condition outside the normal environment. These or...

Lecture 2 Dr. Eman El Gebaly  Not do a lot, but what do, do well Microbes have Extremophiles small genomes Having optimal condition outside the normal environment. These organism survive, reproduce and grow in extreme or unusual enviroment on the earth. 1- Thermophiles – Heat Loving "Thermopillic microorganisms" are heat loving which can grow in the temperature 55-65 °C. Minimum growth temperature: 45°C. Optimal growth temprature: 55- 65°C Maximum growth temperature: 110 °C. They contain heat-stable enzymes. Used in biotechnology Example:-Thermus aquatics and Thermococcus littorals are used as sources of the enzyme DNA polymerase, for the PCR. Dr. Eman El Gebaly 2-Psychrophiles - Cold Loving Most psychrophiles are bacteria or archaea. Psychrophiles are also called as Cryophiles. found in Antarctic oceans & deep ocean. They are capable of growth and reproduction in cold temperatures, ranging from 4°C to +15°C. They have the cold –active enzyme and special proteins or cryoprotectants called antifreeze proteins. Examples are Arthrobacter sp. and psychrobacter sp.. Dr. Eman El Gebaly 3-Osmophiles :-sugar loving organism Osmophillic organisms are able to grow in high sugar concentration. osmophiles protect themselves against this high osmotic pressure by the help of osmo protectants such as alcohols and amino acids. Osmophile are important because they cause spoilage in the sugar and sweet goods industry. Example of osmophiles is Aspergillus, Saccharomyces, Enterobacter aerogenes and Micrococcus. Dr. Eman El Gebaly 4-Halophiles:-salt loving organisms are organisms that live in high salt concentrations. most halophiles are aerobic and heterotrophic. some are anaerobic and photosynthetic. Example :- halobacterium , halococcus Dr. Eman El Gebaly 5- Alkalophiles:- They grow at the PH 9 and above. isolated from alkaline environments. cell surface play a key role in keeping the intracellular pH value in the range between 7 and 8.5. Used in:- Biological detergents and Enzyme production. Example:- bacillus okhensis ,alkalibacterium sp. 6-Acidophiles:-acid loving organism They grow at pH 3 or below these organisms have the ability to pump hydrogen ions out of their cells. The internal pH of the cell is about 6.5 & external pH is about 2.5 or less Used:- Enzyme production. Dr. Eman El Gebaly 7-Methanogens Methane producing bacteria Methanogens belong to the Archaea group of the Prokaryotes. Methanogens are bacteria that produce methane gas. Methanogens require anaerobic conditions. Many require warm conditions to work best.. They can be used as sources of biogas gas. This would be a renewable source of energy. Examples: Methanobacterium and Methanococcus Dr. Eman El Gebaly  8-Methylotrophs: Methane degrading organism They are aerobic organism that can use reduced one carbon compounds, such as methanol or methane as a carbon and energy source. may grow on other organic molecules including Organic acids Ethanol and sugars. Example: Methylosinus sp.& Methylococcus capsulatus (is used to degrade methane and other pollutants ) Dr. Eman El Gebaly Dr. Eman El Gebaly Assimilative processes are Dissimilative processes do used to bring needed not incorporate elements elements into the cell and into the cell, but instead to incorporate them into they use the energy gained the cell protoplasm. in the process to form ATP. Dr. Eman El Gebaly  Autotrophs derive energy from either light absorption (photoautotrophs) Microorganisms are classified as autotrophs oxidation of inorganic molecules (chemoautotrophs). or heterotrophs based on whether or not they require pre-formed Some photosynthetic bacteria (photoheterotrophs) require pre- organic matter. formed organic matter as reducing agents, but generate ATP from the absorption of light energy. Dr. Eman El Gebaly Classification Energy source Source of Example of for generating carbon for the organisms ATP cell Photoautotroph Light CO2 Bacteria, plants Chemoautotroph Inorganic CO2 Bacteria compounds Photoheterotroph Light CO2, organic Bacteria matter Heterotroph Organic matter Organic Bacteria, fungi, matter animals Dr. Eman El Gebaly  Ecological role of microorganisms Microorganisms in ecosystems can have two complementary roles: (1) the synthesis of new organic matter from CO2 and other inorganic compounds during primary production and (2) de- composition of this accumulated organic matter. Dr. Eman El gebaly  Microbial ecosystems – Aquatic An aquatic ecosystem is an ecosystem in water. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. The primary production of our aquatic ecosystems is governed by the supply of essential nutrients, of which nitrogen is one of the most important. Dr. Eman El gebaly  Microbial ecosystems – terrestrial Terrestrial ecosystems are distinguished from aquatic ecosystems by the lower availability of water and the consequent importance of water as a limiting factor. Dr. Eman El gebaly  Microbial Community?? Diversity: Assessing microbial diversity means answering the question: What microbes are presentand what are their characteristics? Abundance: Assessing microbial abundance means answering the question: How “many” microbes are present in terms of numbers and/or biomass? Activity: Assessing microbial activity means and answering the question: What are the microbes doing and as a result, how are they impacting the abiotic and biotic environment? Dr. Eman El gebaly  Biogeochemical Cycles or Nutrient cycles: Is how elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another. Types of Biogeochemical Cycle: Atmospheric- carbon cycle and nitrogen cycle Sedimentary - phosphorus cycle and Sulphur cycle  Microbial Role in Biogeochemical Cycling A biogeochemical cycle is a pathway by which a chemical element (such as carbon or nitrogen) circulates through the biotic (living) and the abiotic (non-living) factors of an ecosystem. The key collective metabolic processes of microbes (including nitrogen fixation, carbon fixation, phosphorous metabolism, and sulfur metabolism) effectively control global biogeochemical cycling  The carbon cycle: Cyanobacteria: Cyanobacteria, also known as blue-green bacteria, blue-green algae obtain their energy through photosynthesis. Carbon in the form of carbon dioxide (CO2) is readily obtained from the atmosphere, but before it can be incorporated into living organisms it must be transformed into a usable organic form. The transformative process by which carbon dioxide is taken up from the atmospheric reservoir and “fixed” into organic substances is called carbon fixation.  The nitrogen cycle Nitrogen is essential for all forms of life because it is required for synthesis of the basic building blocks of life (e.g., DNA, RNA, and amino acids). The Earth’s atmosphere is primarily composed of nitrogen, but atmospheric nitrogen (N2) is relatively unusable for biological organisms. Consequently, chemical processing of nitrogen (or nitrogen fixation) is necessary to convert gaseous nitrogen into forms that living organisms can use. Almost all of the nitrogen fixation that occurs on the planet is carried out by bacteria that have the enzyme nitrogenase, which combines N2 with hydrogen to produce a useful form of nitrogen (such as ammonia).  Nitrifying bacteria convert the most reduced form of soil nitrogen, ammonia, into its most oxidized form, nitrate. Denitrifying bacteria capable of performing denitrification as part of the nitrogen cycle. They metabolise nitrogenous compounds using various enzymes, turning nitrogen oxides back to nitrogen gas or nitrous oxide. THANK YOU