#Biocontrol Agents In Human Welfare How To Fight The

They are small enough not to be seen by our naked eyes. Microbes or microorganisms are tiny single-celled creatures. The document Microbes As Biocontrol Agents & As Biofertilizers NEET Notes EduRev is a part of the NEET Course Biology Class 12.

Biological control agents are natural enemies of insect and pests. These chemicals are toxic and extremely harmful, to human beings and animals alike, and have been polluting our environment (soil, ground water. Use of chemicals like insecticides and pesticides causes great harm.

Microorganisms include bacteria, fungi, protozoa, some algae, viruses, viroids and also prions. Useful Microbes – Microbes In Human Welfare Biological control of pests and diseasesUseful Microbes – Microbes In Human Welfare: Microbes in the production of Antibiotics, Vaccines, Curd, Fermented beverages, Biogas, Biofertilisers etc. It produces a toxin called as Bt toxin which is toxic to insects. An example of a microbial biocontrol agent includes Bacillus thuringiensis.

The source of these medicines is microorganisms. Whenever you fall ill the doctor may give you some antibiotic tablets, capsules or injections such as of penicillin. This post is about such useful microorganisms. Some other microorganisms are beneficial and contribute to human welfare. A list of common diseases caused by microorganisms are given in the previous post. Some microorganisms are harmful as they cause various diseases in humans.

Suddenly he found the spores of a little green mould in one of his culture plates. In 1929, Alexander Fleming was working on a culture of disease-causing bacteria. Streptomycin, tetracycline and erythromycin are some of the commonly known antibiotics which are made from fungi and bacteria. These days a number of antibiotics are being produced from bacteria and fungi. Such medicines are called ANTIBIOTICS.

Antibiotics, however, are not effective against cold and flu as these are caused by viruses. Antibiotics taken unnecessarily may kill the beneficial bacteria in the body. Today, we cannot imagine a world without antibiotics. Antibiotics have greatly improved our capacity to treat deadly diseases such as plague, whooping cough, diphtheria and leprosy, which used to kill millions all over the globe. From this the mould penicillin was prepared. In fact, it also killed many of these bacteria.

Biocontrol Agents In Human Welfare How To Fight The

Edward Jenner discovered the vaccine for smallpox in 1798.Chemicals, Enzymes and other Bioactive Molecules Several diseases, including cholera, tuberculosis, smallpox and hepatitis can be prevented by vaccination. This is how a vaccine works. The antibodies remain in the body and we are protected from the disease-causing microbes. So, if dead or weakened microbes are introduced in a healthy body, the body fights and kills them by producing suitable antibodies. The body also remembers how to fight the microbe if it enters again.

Clostridium butylicum (a bacterium) of butyric acid Acetobacter aceti (a bacterium) of acetic acid Aspergillus niger (a fungus) of citric acid Examples of acid producers are

Another bioactive molecule, cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Tnchoderma polysporum. Streptokinase produced by the bacterium Streptococcus and modified by genetic engineering is used as a ‘clot buster’ for removing clots from the blood vessels of patients who have undergone myocardial infraction leading to heart attack. This is because the bottled juices are clarified by the use of pectinases and proteases. You must have noticed that bottled fruit juices bought from the market are clearer as compared to those made at home. Lipases are used in detergent formulations and are helpful in removing oily stains from the laundry. Yeast (Saccharomyces cerevisiae) is used for commercial production of ethanol.

The puffed-up appearance of dough is due to the production of CO2 gas which is released by the microbes. The dough, which is used for making foods such as dosa and idli is fermented by bacteria. Louis Pasteur discovered fermentation in 1857. This process of conversion of sugar into alcohol is known as fermentation.

Cheese, is one of the oldest food items in which microbes were used. Microbes are also used to ferment fish, soyabean and bamboo- shoots to make foods. ‘Toddy’, a traditional drink of some parts of southern India is made by fermenting sap from palms. A number of traditional drinks and foods are also made by fermentation by the microbes.

Many of which are pathogenic. Sewage contains large amounts of organic matter and microbes. Wine and beer are produced without distillation whereas whisky, brandy and rum are produced by distillation of the fermented broth. Depending on the type of the raw material used for fermentation and the type of processing (with or without distillation) different types of alcoholic drinks are obtained. For this purpose the same yeast Saccharomyces cerevisiae used for bread-making and commonly called brewer’s yeast, is used for fermenting malted cereals and fruit juices, to produce ethanol. Microbes especially yeasts have been used from time immemorial for the production of beverages like wine, beer, whisky, brandy or rum.

This significantly reduces the BOD (biochemical oxygen demand) of the effluent. While growing, these microbes consume the major part of the organic matter in the effluent. This allows vigorous growth of useful aerobic microbes into flocs (masses of bacteria associated with fungal filaments to form mesh like structures). The primary effluent is passed into large aeration tanks where it is constantly agitated mechanically and air is pumped into it. The effluent from the primary settling tank is taken for secondary treatment.

The greater the BOD of waste water, more is its polluting potential. BOD is a measure of the organic matter present in the water. The sewage water is treated till the BOD is reduced.

These gases form biogas and can be used as source of energy as it is inflammable. During this digestion, bacteria produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide. Here, other kinds of bacteria, which grow anaerobically, digest the bacteria and the fungi in the sludge. The remaining major part of the sludge is pumped into large tanks called anaerobic sludge digesters. A small part of the activated sludge is pumped back into the aeration tank to serve as the inoculum or starter. This sediment is called activated sludge.

These bacteria are also present in the rumen (a part of stomach) of cattle. These bacteria are commonly found in the anaerobic sludge during sewage treatment. These bacteria are collectively called methanogens, and one such common bacterium is Methanobacterium. Certain bacteria, which grow anaerobically on cellulosic material, produce large amount of methane along with CO2 and H2. Biogas is a mixture of gases (containing predominantly methane) produced by the microbial activity and which may be used as fuel.

Biological agents are a better alternative to weedicides and pesticides. Biocontrol refers to the use of biological methods for controlling plant diseases and pests. Dung can be used for generation of biogas, commonly called gobar gas. Thus, the excreta (dung) of cattle, commonly called gobar, is rich in these bacteria. In rumen, these bacteria help in the breakdown of cellulose and play an important role in the nutrition of cattle.