Aspects of Biotechnology in Microbial Ecology

Functions of microorganisms in microbial colony

1) Microorganism as pollutants

Salmonella can be found both inside and outside of eggs. Normally, eggs can be infected by fecal contamination when the egg exits the hen's body or by dirt from surroundings. That is why the eggs are washed and sanitized at the processing plant. Bacteria can also be inside an uncracked, whole egg. Contamination of eggs may be due to Salmonella within the hen's ovary or oviduct being transferred into the contents of yolk and white before the shell forms. Over the years, however, scientists have found that Salmonella Enteritidis has the ability to grow both in the egg yolk and white.

Keeping eggs adequately refrigerated prevents any Salmonella present in the eggs from growing to higher numbers, so eggs should be refrigerated until they are needed. Moreover, cooking reduces number of bacteria in eggs due to the use of high temperature.

Symptoms of Salmonella infection: (12-72 hours after consumption of contaminated food)
- Fever
- Abdominal pain
- Diarrhea

Actions that can be taken to reduce Salmonella infection from eggs
- Discard cracked eggs
- Keep eggs from refrigerated
- Avoid consumption of raw eggs.
- Eggs should be fully cooked

2) Microorganism cause of pollution

Methylmercury is a neurotoxin that poses significant health risk to human. It is formed by the action of anaerobic bacteria. They turn inorganic mercury into methyl mercury.

3) Microorganism as indicator of pollution

Dr mentioned that if E. coli is found in water, it has a high possibility that the water is contaminated with faeces.

4) Microorgnism may reduce pollution

For example, Rhodococcus can be used in oil degradation.

Extra information

- If we want to increase the production of microbes, bioreactor is used which the volume is up to 1000L.


- Pesticide such as DDL is toxic in high concentration. It function through interfering the synthesis of chitin. Thus it will disturb the development of insects such as grasshopper since the head, thorax and body is mostly made up by chitin.

- Superbug is resistant to antibody

-Thiram is a fungiside. It is used to prevent fungal disease in seed and crops. Besides, it also acts like an animal repellent to protect fruit trees and ornamental( plant that is grown for its beauty and decorative value) from damage by rabbits and rodents.

Water related disease

- What is Methaemoglobinemia? 
Reduction of ability of blood to carry oxygen due to reduced level of haemoglobin.

- Who will be the victim?
Infants are most infected. They may seem healthy, but show the sign of blueness around the mouth, hands and feets. This is why they are given the name 'Blue baby syndrome'.

- What are the syndrome?
These children will have breathing difficulties,continuous vomiting and diarrhoea.

- What is the cause?
High concentration of nitrate in drinking water, especially in bottle fed infants and water from well in rural areas. The source of nitrate comes from manure and fertiliser on agriculture land.

- How does it work?
In human body, nitrates will be converted to nitrites. Nitrites is then react with haemoglobin in red blood cell to form methaemoglobin, affecting the body's ability to carry oxygen.