Question

Write short notes:

Useful and harmful bacteria

Answer 1

1. Useful bacteria:
   Most of the bacteria act as a decomposer. They breakdown large molecules into 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 the 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.
2. 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, Pasteurella, etc.