What useful microorganisms are there

An example of microbial biocontrol agents that can be Introduced in order to control butterfly caterpillars is the bacteria Bacillus thuringiensis often written as Bt. These are available in sachets as dried spores which are mixed with water and sprayed onto vulnerable plants such as brassicas and fruit trees, where these are eaten by the insect larvae. In the gut of the larvae, the toxin is released and the larvae get killed.

The bacterial disease will kill the caterpillars, but leave other insects unharmed. Because of the development of methods of genetic engineering in the last decade or so, the scientists have introduced thuringiensis toxin genes into plants.

Such plants are resistant to attack by insect pests. Bt-cotton is one such example, which is being cultivated in some states of our country. A biological control being developed for use in the treatment of plant disease is the fungus Trichoderma. Trichoderma species are free-living fungi that are very common in the root ecosystems.

They are effective biocontrol agents of several plant pathogens. Baculoviruses are pathogens that attack insects and other arthropods. They have been shown to have no negative impacts on plants, mammals, birds, fish or even on non-target insects. Microbes as biofertilisers Biofertilisers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilisers are bacteria, fungi and cyanobacteria. You may be knowing about the nodules on the roots of leguminous plants formed by the symbiotic association of Rhizobium.

These bacteria fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient. Other bacteria can fix atmospheric nitrogen while free-living in the soil examples Azospirillum and Azotobacter , thus enriching the nitrogen content of the soil.

Fungi are also known to form symbiotic associations with plants mycorrhiza. Many members of the genus Glomus form mycorrhiza. The fungal symbiont in these associations absorbs phosphorus from soil and passes it to the plant. Plants having such associations show other benefits also, such as resistance to root-borne pathogens, tolerance to salinity and drought, and an overall increase in plant growth and development. Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen , e.

Anabaena, Nostoc, Oscillatona, etc. In paddy fields, cyanobacteria serve as an important biofertiliser. Blue green algae also add organic matter to the soil and increase its fertility. Preservatives Salts and edible oils are the common chemicals generally used to check the growth of microorganisms. Therefore they are called preservatives. We add salt or acid preservatives to pickles to prevent the attack of microbes.

Sodium benzoate and sodium metabisulphite are common preservatives. These are also used in the jams and squashes to check their spoilage. Common salt has been used to preserve meat and fish for ages. Meat and fish are covered with dry salt to check the growth of bacteria. Salting is also used to preserve amla, raw mangoes, tamarind, etc. Jams, jellies and squashes are preserved by sugar. Sugar reduces the moisture content which inhibits the growth of bacteria which spoil food.

Use of oil and vinegar prevents spoilage of pickles because bacteria cannot live in such an environment. Vegetables, fruits, fish and meat are often preserved by this method. Pasteurized milk can be consumed without boiling as it is free from harmful microbes. The milk is heated to about 70 0 C for 15 to 30 seconds and then suddenly chilled and stored.

By doing so, it prevents the growth of microbes. This process was discovered by Louis Pasteur. It is called pasteurization. Summary Microbes are a very important component of life on earth. Not all microbes are pathogenic. Many microbes are very useful to human beings. We use microbes and microbially derived products almost every day.

Bacteria called lactic acid bacteria LAB grow in milk to convert it into curd. The dough, which is used to make bread, is fermented by yeast called Saccharomyces cerevisiae.

Certain dishes such as idli and dosa, are made from dough fermented by microbes. Bacteria and fungi are used to impart particular texture, taste and flavor to cheese. Microbes are used to produce industrial products like lactic acid, acetic acid and alcohol, which are used in a variety of processes in the industry. Antibiotics like penicillins produced by useful microbes are used to kill disease-causing harmful microbes.

Antibiotics have played a major role in controlling infectious diseases like diphtheria, whooping cough and pneumonia. For more than a hundred years, microbes are being used to treat sewage waste water by the process of activated sludge formation and this helps in recycling of water in nature. Methanogens produce methane biogas while degrading plant waste. Viruses are almost always thought of as agents of disease.

This is because the ones that cause disease are the ones that have been studied. About half the plants have viruses, but most don't seem to be sick at all. The viruses seem to be living in the plants without doing any harm. Recently we stressed some plants that were infected with viruses by not watering them. This was part of another experiment, but, to our surprise, all of the plants infected by viruses were much more tolerant of drought. The plants included 10 different species, and we used four different viruses.

In all cases, the virus-infected plants did much better under drought stress. Drought-stressed rice plants after six days without water. The plant on the right is infected with Brome mosaic virus; the one on the left is "healthy" i.

This lactic acid bacteria improves nutritional quality by enhancing vitamin B The dough we prepare for idli, dosa, is fermented using fungi and bacteria. In many traditional drinks and foods, fermentation happens using bacteria.

Eg: Toddy. Microbes can help fish, soybean, and bamboo shoots in fermentation. Propionibacterium shermanii helps in the making of swiss cheese. Ripening of Roquefort cheese is done by growing fungi on them to produce distinct flavor.

Microbes in industrial products:. Many antibodies and beverages can be manufactured using microorganisms. Yeast assists the fermentation process in the manufacturing of wine, Whisky, Rum. Saccharomyces cerevisiae or brewer's yeast aids the fermentation of malted cereals, fruit juices to produce ethanol.

Microbes in Antibiotics:. Penicillin, the first antibiotic discovered, is also developed using a microorganism known as Penicillium notatum. This penicillin helped in healing for wounded soldiers during world war II.

Some other fatal diseases like Plague, whooping cough, Diphtheria, and leprosy can be treated using these antibiotics produced from microorganisms. Microbes in sewage treatment:. Bacteria help to treat sewage water from municipal waste.

It uses anaerobic respiration, BOD, etc. Microbes in production of biogas:. Methanogen bacteria help in the production of biogas. Microbes in chemicals, enzymes, and other bioactive molecules:.

Aspergillus niger is present in citric acid. It is a fungus. Acetobacter acetic is available in acetic acid. Clostridium butylicum bacteria in butyric acid. Lactobacillus is present in lactic acid. Lipases are an essential part of detergents. Pectinases help in storing the bottled juices. Streptokinase enzyme used to remove blood clots from the blood vessels of myocardial infarction patients.

Cyclosporin A acts as an immunosuppressive agent, and Cyclosporin A enzyme is produced by the eubacterium Trichoderma polysporum. Monascus purpureus yeast produces statins which are used as blood cholesterol-lowering agents. Microbes are used in various parts of our day to day life, including some industries, and they are equally useful for nature.

Some fungi and bacteria species help in the creation of steroids, which are used to inject to humans for various purposes.