Streptomycin is extracted from the fermentation broth using an organic solvent in a counter-current staged extraction unit. The distribution coefficient of streptomycin at pH = 4 is KD = Yi/Xi = 40, and the flow rate of the aqueous (H) phase is H= 150 L/min. If only five extraction units are available to reduce the streptomycin concentration from 10 g/L in the aqueous phase to 0.2 g/L, determine the required flow rate of the organic phase (L) in the extraction unit.

6.75l l/min

Explanation:

Streptomycin is extracted  from the fermentation broth using an organic solvent in a counter current staged extraction unit.

for 5 stage counter current staged extraction unit for streptomycin

X5 = 0.2g/l

X0 = 10.0g/l

X5/X0 = 0.02

given

Xn/X0, E, and

n = 5

A estimate of E  can be evaluated directly;

E = 1.8

= LKd/H

by substituting the given values; Kd = 40, H= 150l/min

then we have,

L;L = 1.8(150)/40

= 6.75l l/min

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.

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