1 Answers
(i) Useful bacteria: Most of the bacteria act as a decomposer. They breakdown large molecules in simple molecules or minerals.
Examples of some useful bacteria:
Lactobacillus: It helps in curdling of milk. Azotobacter. It helps to fix nitrogen for plants.
Streptomyces: It is used in antibiotic production such as streptomycin.
Methanogens: These are used for production of methane (biogas) gas from dung. Pseudomonas spp. and
Alcanovorax borkumensis: These bacteria have the ability to destroy the pyridines and other chemicals. Hence, used to clear the oil spills.
(ii) Harmful bacteria: This includes disease causing bacteria. They cause various diseases like typhoid, cholera, tuberculosis, tetanus, etc.
Examples of some harmful bacteria:
Salmonella typhi: It is a causative organism of typhoid.
Vibrio cholerae: It causes cholera. Mycobacterium tuberculosis’. It causes tuberculosis.
Clostridium tetani: It causes tetanus.
Clostridium spp: It causes food poisoning. Many forms of mycoplasma are pathogenic. Agrobacterium , Erwinia, etc are the pathogenic bacteria causing plant diseases. Animals and pets also suffer from bacterial infections caused by Brucella, Pastrurella, etc.