Laboratory fermentation

1. Laboratory fermentation
{production of ethyl alcohol from molasses}
by
SRI P. KRISHNA REDDY
Lecturer in chemical engineering
Gov. institute of chemical engineering
Visakhapatnam
Andhra Pradesh
India

17. Ethyl Alcohol from Sugar solution (Molasses):-
Molasses is a non-crystalline of sugar obtained as mother liquor after
crystallization of sugar from sugar solution. This contains about 50% sugar. It is
diluted to about 10% solution. The process can be explained in the following
two stages:
a) Cultivation of Yeast in the molasses.
b) Recovery of Ethyl alcohol from cultivated solution.

18. Releasing of
carbon -dioxide is
observed
Stage 1
Heating of
distilled
water
+
Addition
of sugar
+
yeast
Stage 5
Stage 2
Stored in cans
and kept for
observation
for cultivation
Of yeast
Stage 3
Stage 4

19. I stage:
As shown in the diagram diluted solution is heated up
to above room temperature (40-50oC) and then yeast is
added proportionality and kept for cultivation for about
2-3 days. Yeast supplies the enzymes invertase and
zymase. The enzyme invertase hydrolysis sucrose to
glucose and fructose. The enzyme zymase converts
glucose to ethanol and carbon dioxide.
Heating of
distilled water
+
Addition of sugar
+
yeast

20. The formation of final products i.e., ethanol and carbon dioxide
can be observed by the bubbler (expanded bubbler) which is
tied to the cultivation can be observed in the diagram.
The fermented liquid which contains about 8-10% ethanol is
called “Wash”.

21. II Stage:
As observed in the diagram the “mash” is collected and
fractionally distilled to recover rectified spirit containing 95.6%
alcohol. The final rectified alcohol is stored in cans. Further
dehydration with quick lime and distilling with sodium or calcium
gives 99.8% ethanol called absolute alcohol.

22. Laboratory fermenter