Which of the following yields citric acid?
1.  Penicillium citrinum
2. Aspergillus niger
3. Saccharomyces
4.  Azospirillium

Saccharomyces cerevisiae is used in the formation of:
1. Ethanol
2. Methanol
3. Acetic acid
4. Antibiotics

Modern farmers can increase the yield of Paddy up to 50% by the use of:
1.  Cyanobacteria
2.  Rhizobium
3.  Cyanobacteria in Azolla pinnata
4.  Farm yard manure

The most thoroughly studied of the known bacteria-plant interactions is the:
 

The dough kept overnight in warm weather becomes soft and spongy because of:

1. Fermentation

2. Cohesion

3. Osmosis

4. Absorption of carbon dioxide from the atmosphere

Which one of the following pairs is not correctly matched:

1. Serratia – Drug addiction

2. Spirulina – Single-cell protein

3. Rhizobium – Biofertilizer

4. Streptomyces – Antibiotic 

A major component of gobar gas is:

1. Methane

2. Ethane

3. Butane

4. Ammonia 

A free-living nitrogen-fixing cyanobacterium that can also form a symbiotic association with the water fern Azolla is:

1. Chlorella

2. Nostoc

3. Anabaena

4. Tolypothrix

Common indicator organism of water pollution is:

1. Eichhornia crassipes

2. Escherichia coli

3. Entamoeba histolytica

4. Lemna pancicostata 

Azolla is used in the cultivation of: