How are bacteria beneficial and how is it harmful?

Answer 1

Sometimes bacteria are beneficial.
1. Bacteria decompose dead organic matter and wastes from living things to put minerals back into the soil.
2. Bacteria fix nitrogen, taking atmospheric nitrogen and changing it into a nitrogen compound which plants can take up.
3. Some bacteria are photosynthetic, so they start food chains and make oxygen.
4. Some bacteria are chemosynthetic, so they start food chains near deep ocean vents.
5. Bacteria are the sources for some of our antibiotics.
6. Bacteria can be genetically engineered to make chemicals for human use.
7. Bacteria help make many foods such as yogurt, sauerkraut, and pickles.
8. Bacteria help organisms digest certain foods.

Harmful:
1. Bacteria cause infections and diseases, as well as producing toxins that can make people sick. Tuberculosis, pneumonia, scarlet fever, botulism
2. Bacteria spoil food causing economic loss and less food in the world.
3. Denitrifying bacteria take nitrogen from compounds in the ground and return it to the atmosphere in the form of nitrogen gas which plants cannot use directly.
4. Bacteria produce methane gas which is a major greenhouse gas - especially anaerobic bacteria in the digestive systems of livestock, in sanitary landfills, in the waterlogged soils of swamps, ...

Answer 2

False. Beneficial or harmful, the terms are relative. Beneficial microbes can become harmful under certain conditions, and vice versa. Whether we as humans consider an organism useful is a whole other topic - we are able to artificially control bacteria in reactors, and we can bioengineer to produce organisms with desirable metabolic processes... that said, most bacteria exist without any decided impact (positive or negative) on people.