Activated sludge should have the ability to settle quickly so that it can
be rapidly pumped back from sedimentation tank to aeration tank
absorb pathogenic bacteria present in waste water while sinking to the bottom of the settling tank
be discarded and anaerobically digested
absorb colloidal organic matter
$$ \text { Match the following columns. } $$
| Column I | Column II | ||
|---|---|---|---|
| A. | Lady bird | 1. | Methanobacterium |
| B. | Mycorrhiza | 2. | Trichoderma |
| C. | Biological control | 3. | Aphids |
| D. | Biogas | 4. | Glomus |
Codes
A B C D
$2 \quad 4 \quad 3 \quad 1$
Codes
A B C D
$3 \quad 4 \quad 2 \quad 1$Codes
A B C D
$\begin{array}{llll}\text { } 4 & 1 & 2 & 3\end{array}$
Codes
$3 \quad 2 \quad 1 \quad 4$
$$ \text { Why does 'Swiss cheese' have big holes? } $$
The large holes in 'Swiss cheese' are due to production of a large amount of $\mathrm{CO}_2$ by a bacterium named Propionibacterium sharmanii.
What are fermentors?
For large scale production of biotechnological products, e.g., antibiotics, beverages) in industries, microbes are grown in very large vessels called fermentors or bioreactors.
$$ \text { Fermentors } $$
Name a microbe used for statin production. How do statins lower blood cholesterol level?
Statins are bioactive molecules, produced by the yeast Monascus purpureus. These bioactive molecules have been commercialised as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.