Microorganism have major impact on human life by their beneficial and harmful activities since time immemorial and the pathogenic microbes have been a cause of worry for te society .

Role in Food industry
Bacteria play an important role in fermentation so that they are use for manufacturing butter, yogurt, cheese, cakes and beer. Alcohol beverages are produced by fermentation of carbohydrates substrate (present either in grains or fruits) by yeast ( saccharomyces cervesia) .
Bacteria are also used in the production of wine and vinegar which uses bacteria like acetobacter and glucanocetobacter which oxidize ethanol to acetic acid.

Fermentation Food
In Japan and China a number of fermented meat and fish products are consumed. Sausages , hams , salami etc are fermented using pediococcus cerevisiae and Lactobacillus plantarum.
Sauerkraut a fermented product of cabbage is consumed worldwide. The fermenting bacteria include Leucconostoc mesenteroids , Lactobacillus plantarum and Lactobacillus brevis.
Kimchi , a food made by cabbage and other vegetable is made by lactic acid bacteria and. Is common in korea.
Probiotics are similiar to curd consisting usually of live microorganism which are taken orally to promote good health and used as health supplements.
Cheese
Commerical variety of cheese is available and formation of this entire cheese making involves lactic acid fermentation of milk. Lactococcus lactis or Lactococcus cremoris are used for fermenting the milk.
Role in Pharmaceutical
Many antibiotics are obtained from bacteria such as Streptomycin , terramycin etc
Antibiotics
Antibiotic are compounds produced by microorganism which either kill the target pathogen or inhibit its growth. One of the most common antibiotics produced by bacteria is Streptomycin.
Vaccine.
Bacteria are used yo produce vaccines by either separating their antigens or sometimes even as dead or alive one form taht lacks pathogenic character. TB vaccine is against tuberculosis (Mycobacterium Tuberculosis) where dead bacteria of TB are administered to build up resistance to tuberculosis in human.
Hormones.
Naturally occuring strains of bacteria produce a variety of compounds medical significant hormones
Energy Production
Teh entire world is facing teh problem of shortage of energy. Bacteria are sued to produce biogas. Biogas is used as alternative resources of energy . oraganic waste can be converted into usable forms of energy
Mining industry
Bacteria are also used for the extraction of metals from mines . Now recombinant bacteria have been prepared which selectively extract metals from raw ore . the microbes such as Thiobacillus thioxidans and Thiobacillus are involved in booming to produce acid.
Bioremediation
Bioremediation is the process of adjustment of environment to enhances teh degradation or transformation of environmental pollutants by micro organisms. Bacteria can degrade a variety of organic compounds thus they are used in waste processing and bioremediation.
Biological Control
The commonly used bacteria biological control are Bacillus thuringiensis ( also called BT) ‚it is a growth positive , soil dwelling bacterium. Subspecies of this bacterium are used as Lepidopteran specific insecticides . because of their specificity , these pesticides are regarded as environmentally friendly
Bio fertilizer
Bio fertilizers contains live beneficial microorganism and certain plant nutrient ( amino acids , growth hormone, trace elements etc) which promote plant growth. They ecofriendly, cost effective and renewable and commonly mixed with soil to help growth.

Textile, Leather and Tobacco industry
Some bacteria lile clostridium are used for letting of hemp, jute and flax. These bacteria seprate the fibres . these fibres are used for making clothes and ropes . Bacteria are used for preparing commercial leather. Bacteria are used for drying tobacco leaves. These are used for preparing cigarettes.