A bioreactor or sludge digester is a large and closed tank where sludge is separated and stored. In the bioreactor, the sludge is decomposed by the action of anaerobic bacteria (bacteria that can respire without oxygen). These anaerobes produce biogas through the process of fermentation. Biogas is a renewable fuel that contains majorly a gas called methane.

Now-a-days the farmers preferred the natural predators of pests than chemical pesticides. Support this statement with example.

The organisms that harm crops and their products are known as pests that include insects, fungi, weeds, large animals, etc. The living organisms that are the natural predators of pests and used to destroy these pests are called biopesticides. Organic farmers adopt a method to control pests where the insects are not eradicated but are kept at manageable levels. They control pests and diseases by utilising natural predation instead of introducing chemicals. The use of viruses, bacteria, and other insects for controlling pest and pathogen is called biocontrol or biological control. Microbial biocontrol agents are species-specific pesticides. The biological pests control method is generally preferred by the organic farmers because it saves the environment from the pollution and the humans from diseases. One of the example of a biopesticide is the bacterium Bacillus thuringiensis . The spore of this bacterium synthesises an insecticidal crystal protein that destroys the egg of some insects. It does not harm the plant and not cause any harm in the environment.

Name two genetically modified bacteria which are used for the production of improved quality of alcohol.

Genetic engineering is a process for the production of transgenic organisms that carry the gene of interest (foreign gene) for the production of desired products. Clostridium acetobutylicum and Escherichia coli are two genetically modified bacteria that are used for the production of improved quality of alcohol. The genes that code for enzymes responsible for the fermentative pathway for alcohol production is inserted into these bacteria through rDNA technology by using appropriate vectors.

A bioreactor or sludge digester is a large and closed tank where sludge is separated and stored. In the bioreactor, the sludge is decomposed by the action of anaerobic bacteria (bacteria that can respire without oxygen). These anaerobes produce biogas through the process of fermentation. Biogas is a renewable fuel that contains majorly a gas called methane.