Bài giảng - Applications of microbes in environment and agriculture

Applications of Microorganisms in Agriculture and Environment... Applications of Microorganisms in Agriculture...  The transfer of genetic information from one organism to another  Met

Applications of Microorganisms

in Agriculture and Environment

Applications of

Microorganisms in

Environment

is the use of microorganism metabolism

to remove pollutants

We Use Existing Microbes

 To clean up oil spills

Decomposition by Microbes

Figure 27.8

Components of agent orange

We Use Existing Microbes

 To leach ores

In addition to the oxidation of sulfur and sulfur

compounds Thiobacillus ferrooxidans is able

to oxidize ferrous to ferric iron and so derive its energy from this exergonic reaction

2Fe++ + 2H+ + ½O2  >    2Fe+++ + H20 

2Fe+++ + 6H20       >    2Fe(OH)3 + 6H+

2Fe++ + 5H20 + ½O2   >    2Fe(OH)3 + 4H+ 

Wastewater treatment

 CO2 + 4 H2  CH4 + 2 H2O

 CH3COOH  CH4 + CO2

Anaerobic Sludge Digester

Figure 27.23

We Use Existing Microbes

 To turn trash into soil

Applications of Microorganisms in Agriculture

Basic Principles of Recombinant DNA Technology

 The transfer of genetic information from one organism to another

 Methods and techniques are known as

Recombinant DNA Technology

Steps in Recombinant DNA

Technology

1. Cleaving (cutting) the target DNA

2. Ligating the target DNA into a vector

3. Transformation of a host cell with the

recombinant DNA (vector DNA with

DNA insert)

4. Screening of cells for those harboring

the recombinant DNA or producing the appropriating protein product

Examples of applications of

genetic engineering in agriculture

Insect resistant plants

What is Bt and how does it work?

 Bacterium Bacillus thuringiensis produces protein, delta-endotoxin,

that is toxic to insects in orders Lepidoptera, Coleoptera (beetles)

- Bt toxin in form of powder used as insecticide spray  applied

to leaves where larvae feed on

2 Toxin binds to specific receptors in gut

and insects stops eating.

Mode of action:

1 Insect eats Bt crystals (  ) and

bacterial spores Bt crystals dissolve at

high pH in insect gut.

3 Toxin causes the gut wall to break

down, allowing spores and normal gut

bacteria to enter the body.

4 Insect dies as spores and gut bacteria

proliferate in the body

Genetic engineering of Bt-resistant corn (Bt-corn)

 Clone Bt toxin gene from bacteria and express in plants

 Bt-transgenic plants are resistant to insects, no need for spraying insecticide

Bt-crops for corn borer control

 Currently in crops of

corn (control of corn borer)

cotton (control of bollworm)

 Studies that demonstrate harmful effects of Bt corn on other insects and ecosystems

 effect of Bt-transgenic corn on Monarch

butterfly larvae feeding on milkweed?

Bt corn may harm stream ecosystems

Bt corn may harm stream ecosystems

Bt corn may harm the caddishfly, which serves as food for fish and amphibians Parts of Bt corn, such as leaves, cobs and pollen, can travel as far as 2000 meters away from source areas-a phenomenon that was not considered when

Bt corn was licensed.

Biofuels – Alternatives to Corn

Jatropha curcas - an important feedstock for the production of biofuels

- widespread use in India and Egypt

- fast growing source of oil-bearing nuts that can be pressed to produce biodiesel

- oil for use in generators, sewing machines and small motors

- Glycerin, a by product of Jatropha oil, can also be used to produce soap