Microbes play a very important role in the present world :
1. Microbes in Household Products:
Micro-organisms such as Lactobacillus and others, commonly called lactic acid bacteria(LAB), grow in milk and convert it to curd - which also improves its nutritional quality by increasing vitamin B₁₂.
In our stomach too, LAB play a very beneficial role in checking disease-causing microbes.
The Roquefort cheese is ripened by growing a specific fungi on it, which gives it a particular flavour.
2. Microbes in Industrial Products:
Even in industry, microbes are used to synthesise a number of products valuable to human beings. Beverages and antibiotics are some examples.
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.
The first antibiotic to be discovered, Penicillin is naturally extracted from the mould Pencillium notatum.
3. Microbes in Sewage Treatment:
Treatment of sewage water is done by heterotrophic microbes naturally present in the sewage. In biological sewage treatment, the microbes grown in the large aeration tanks consume the major part of the organic matter in the effluent. The biogas produced by the anaerobic bacteria during the sewage treatment, can be used as a source of energy as it is inflammable.
4. Microbes as biocontrol agents:
A biological control being developed for use in the treatment of plant disease is the fungus Trichoderma. Trichoderma species are effective biocontrol agents of several plant pathogens.
Baculoviruses are pathogens that attack insects and other arthropods. These viruses are used as biocontrol agents and are excellent candidates for species-specific narrow spectrum insecticidal applications.
5. Microbes as Biofertilzers:
The main sources of biofertilizers are bacteria, fungi and cyanobacteria.
The nodules on the roots of leguminous plants are formed by symbiotic association with Rhizobium, which can fix atmospheric nitrogen into organic forms, which is used by the plant as a nutrient.
Many members of the genus Glomus form mycorrhiza. The fungal symbiont in these associations facilitates absorption of phosphorous by the plant from the soil.