Which yeast is used for the production of ethanol from fruit juices?

The rejection of organ transplant in humans is prevented by using

Identify the fungus from the following options.

Read the following statement having two blanks ($A$ and $B$).
$A$ drug used for $A$ patients is obtained from a species of the organism $B$.
The one correct option for the two blanks is

$Bacillus$ $megatherium$ is used in:

Why is sugar repeatedly added in a fed-batch culture?