(i) Prevention of environmental pollution: Bacteria break down the organic wastes of the environment into simple substances. By oxidizing the complex material, making it suitable for reuse. This is why bacteria are called natural scavengers. Bacteria such as Pseudomonas, Nocardia, Mycobacterium etc. convert petroleum waste into simple compounds in the presence of oxygen.
(ii) Healthy sewage system: Bacteria keep the sewage system healthy by rapidly converting organic waste into liquid. Zooglea ramigera bacteria play an important role in organic waste conversion.
(iii) Oil removal: Oil consuming bacteria are used to remove floating oil in sea water. Pseudomonas aeruginosa is an oil-eating bacteria.
(iv) Biological control: Bacteria are used to suppress the larvae of harmful pests.