Microbes play a crucial role in the fermentation process to obtain a number of products. The two common products obtained by fermentation process through industrial processes are fermented-
Beverages: Yeasts are the widely used microorganism for the production of beverages like beer, brandy, rum, wine, whiskey, etc. Yeasts are single-celled, eukaryotic, microorganisms of the Kingdom Fungi. In these industrial process, the species of yeasts, Saccharomyces cerevisiae, generally called as the Brewer’s Yeasts are used for fermenting fruit juices and malted cereals to produce ethanol. Once after the fermentation, these beverages are distilled to produce both Alcoholic and non-alcoholic beverages including whiskey, brandy, rum, etc.
Organic acids: Microbes are also used for the industrial production of certain organic acids. Citric acid was the first discovered organic acids from microbial fermentation of lemon – a citrus fruits. Organic acids are also produced directly from glucose. Aspergillus Niger, Acetobacter acute and Lactobacillus are few examples of microbes used for the industrial production of organic acids.
Enzymes: Enzymes are naturally occurring, biological catalysts that are mainly used to control certain biochemical reactions in the living system. Enzymes have a wide range of applications in the production of both medical and non-medical field. Apart from the plants and animals, enzymes are also obtained from certain microbes and are referred to as the microbial enzymes.
Antibiotic: Antibiotics are chemical substances produced by certain microbes which functions either by killing or retarding the growth of harmful microbes without affecting the host cells. Penicillin was the first antibiotic to be discovered by Alexander Fleming in the year 1928 from the fungus Penicilliumnotatum.
Vitamins: Vitamins are organic compounds which are capable of performing many life-sustaining functions inside our body. They are essential micronutrients which are required in small quantities for the body’s metabolism. As our body cannot be synthesized these vitamins, they need to be supplied through the diet.
It is treated in sewage treatment plans (STPs) before disposing of so as to make it less polluting which is naturally carried out by heterotrophic microbes present in the sewage. The treatment is carried out in two stages – Primary treatment, Secondary treatment or biological treatment
Sewage treatment is carried out in Sewage Treatment Plants (STPs) in following steps:
This step involves physical removal of large and small particles from sewage through filtration and sedimentation.
Floating debris is removed by sequential filtration by passing through wire mesh screens.
After this, the grit (soil and small pebbles) is removed by sedimentation in settling tanks. The sediment is called primary sludge and the supernatant forms the primary effluent.
The effluent is taken for secondary treatment.
Primary effluent is passed into large aeration tanks with constant mechanical agitation and air supply.
This allows vigorous growth of useful aerobic microbes into floes (masses of bacteria associated with fungal filaments to form mesh-like structures).
These microbes consume major part of organic matter in the effluent, while growing. This reduces the Biochemical Oxygen Demand (BOD) of the effluent.
When BOD of sewage gets reduced, it is passed into settling tank.
The bacterial floes settle in tank and the sediment is called activated sludge.
A small amount of activated sludge is pumped back into the aeration tank to serve as inoculum.
The remaining major part of the sludge is pumped into large tanks called anaerobic sludge digesters.
The natural method of eliminating and controlling the insects, pests and other disease-causing agents using their natural, biological enemies is called biocontrol or biological control. The agents which are employed for this are called biocontrol agents. Microbes are one of them.
Biocontrol agents are an integral part of organic farming. In organic farming, farmers believe in mutualism. In other words, organic farmers keep a balance of useful and harmful agents within the system.
The chemicals used for eradicating pest and parasite might not be always successful and also harm useful agents too. Instead, farmers used biocontrol agents which predate the insects and pests that cause diseases to crops. This approach of pest management needs vivid knowledge about the life cycle and feeding habits of different life forms.
The utilization of biological methods to control plants pests and diseases is referred to as biocontrol which has been achieved through chemicals – pesticides and insecticides.
Use of biocontrol measures will reduce the dependence on toxic chemicals and pesticides to a greater extent.
Biological farming promotes life forms such as the inhabiting of the field, pests and predators, life cycles, feeding patterns that willl help in developing suitable means of biocontrol
Microbial biocontrol agents example – Bacillus thuringeinsis, available as dry spores, sprayed on vulnerable plants
Genetic engineering developments have enabled scientists to release B. thuringiensis toxins genes into plant body thereby making them resistant to attacks by insect pests. Example – Bt-cotton
Most of the baculoviruses used as biological control agents are in the genus Nucleopolyhedrovirus.
Biofertilizers are the microbial inoculants which can be usually defined as a preparation containing live or dormant cells of efficient strains of nitrogen fixing, phosphate solubilizing, and cellulytic microorganisms, etc. In contrast to chemical fertilizers, biofertilizers are viable microorganisms which are not the source of nutrients but provide help to plants in accessing the nutrient availability in rhizospheric region.
Several microorganisms are commonly used as biofertilizers including nitrogen-fixing soil bacteria (Azotobacter, Rhizobium), nitrogen-fixing cyanobacteria (Anabaena), phosphate-solubilizing bacteria (Pseudomonas sp.), and AM fungi. Similarly, phytohormone (auxin)-producing bacteria and cellulolytic microorganisms are also used as biofertilizer formulation.
These microbial formulations are used to enhance certain microbial process to increase the availability of nutrients in a form which can be assimilated by plant.
Biofertilizers are low-cost, renewable sources of plant nutrients.
These are the strains of beneficial soil microorganisms which are cultured and packed in suitable carrier in laboratory.
A carrier is a material, such as peat, lignite powder, vermiculite, clay, talc, rice bran, seed, charcoal, soil, rock phosphate pellet, paddy straw compost, wheat bran, or a mixture of such materials, etc. which provides better shelf life to biofertilizer formulation.
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