Title of Invention

"IMPROVED PROCESS OF MANUFACTURING ETHANOL FROM GLUCOSE"

Abstract There is disclosed process for manufacture of Ethanol from Glucose, which comprises subjecting an aqueous solution of around 10% concentration (wt/vol) of glucose by fermentation at around 30°C in the presence of yeast followed by separating Ethanol produced at a P.H. of 4 - 4.5. The fermentation is carried out in the presence of organic solvent as herein described so as to obtain and aqueous phase containing a product of fermentation and organic phase above the aqueous phase having high purity ethanol obtained from fermentation. A suitable conditions for maximum production is also disclosed.
Full Text This invention relates to an improved process of manufacturing ethanol from Glucose.
The conventional way of making ethanol from starch involves either acid or enzymatic hydrolysis followed by fermentation and atmospheric distillation. Anhydrous ethanol is obtained from the ethanol - water azeotrope produced in atmospheric distillation by several ways e.g. using a third component such as benzene to break the azeotrope or using either a hygroscopic solvent or a solid desicant to remove the water from aqueous ethanol.
The conventional processes are both capital and energy intensive. For instance, it takes about 2 0 hours hold up time to complete fermentation of a given batch. Also both capital and energy consumption are high in obtaining anhydrous alcohol using any conventional azeotrope breaking process. A novel process has been conceived which attempts to cut down both fermentation hold up time and capital and energy cost for the production of anhydrous alcohol.
It is known in my earlier Indian Patent No. 173212 as follows :
1. Extractive Fermentation using a suitable organic
solvent to produce 100% ethanol.
2. Use of inert particles of proper shape in the aqueous
medium and vibration of the fermenter to expedite
fermentation by increasing the rate of mass transfer
in and out of the yeast cells.
3. Faster transfer of alcohol from aqueous to organic
phase by recycling alcohol rich solution from bulk
to intefacial region and withdrawal of alcohol
depleted liquid from the interface and dispersal into
the bulk.
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4. Cut down fermentation time and hence the size of the fermentor.
a) Produce 100% alcohol in organic medium. 5" Produce 100% ethanol as one of the product using simple technique of extraction of alcohol into an organic solvent followed by distillation. The process in the said Indian Patent generally consists of simultaneous fermentation and extraction where glucose is fermented to ethanol and ethanol is simultaneously extracted into an organic solvent. The solvent is immiscible with respect of wate; but has high solubility for ethanol and is lighter than the aqueous phase. A list of organic solvents are given below :
1 . 1 - Decanol
2 . Ethyl benzene

3. Isopropyl Benzene
4. M-ethyl toluene
5. N - butyl propionate
Amongst these solvents the desirable ones are those for which the distribution coefficients (which is as is well known the concentration ratio of alcohol between the organic phase and aqueou phase) are higher and boiling points are higher such that substantial amount of alcohol can be extracted into the organic phase and separation of alcohol from the organic solvent will be easier with less capital investment and lower operating cost.
The quantity of organic solvent used depends upon a number of factors as follows :-
a) Volume of aqueous phase and
b) Distribution coefficient.
Fermentation time is reduced due to lowering of alcohol concentration in the bulk caused by its migration to organic phase as it becomes produced. The density convection currents are
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generated dud to diffusion of alcohol out of the aqueous phase into the organic phase due to the affinity of the alcohol produced towards the organic solvent which makes the layers of aqueous phase being depleted of alcohol heavier and hence these layers
(upper layer) sink towards the bottom.

The interface through which alcohol transfer occurs, for faster transfer from the bulk to the interface the aqueous phase can be pumped out from the bulk and discharge it nears the interface continuously during the simultaneous fermentation and extraction process. By maintaining a higher concentration near the interface a larger density gradient can be generated leading to higher rate of transfer. It is necessary to release the pumped liquid near the interface over the whole are uniformly, such that the velocity is reduced as it enters but sufficient to penetrate the whole width of the phase. Due to this operation more solute (alcohol) is absorbed uniformly at the interface and reduces the interfacial tension, which is a measure of energy barrier at the interface for solute transport. Also higher concentration on the aqueous side at the interface will cause higher concentration of it on the organic side leading to higher overall rate of mass transfer.
Reference is invited to the said Patent for further additional details.
As will be appreciated from the above Patent, fermentation of ethanol from, glucose takes place using yeast in the presence of an organic solvent and two distinct phases namely, Aqueous Phase and Organic Phase are obtained, and alcohol is recovered from both the aqueous phase and the organic phase.
In further investigation of the process proposed in the said Patent, it has now...
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said Patent, it has now been discovered that the same starch can be used more effectively as a source for glucose.
It is now found that by modification of the above Patented process it is possible to use starch in the modified process to produce alcohol at a faster rate and at a cheaper cost.
After intensive study and experimentation it has been found that excellent results are obtained if the organic phase is also subjected to recycling techniques as provided for the aqueous phase in the Patented process.
The reason behind this modification is to recover maximum amount of alcohol from glucose at the shortest possible time. In the modified process it has been clearly observed that the rate of transfer of alcohol from the aqueous phase to the organic phase is affected by concentration factors of alcohol in the organic phase. In the earlier Patent the concentration of alcohol near the interface was the maximum and it gradually migrated into the bulk of the organic media. The concentration gradient of alcohol between the aqueous phase and the organic phase at the interface was less and hence the rate of production of absolute alcohol was also affected and more time was required due to slow migration of alcohol from the interphase to the organic phase.
After having understood the drawback I have been able to solve the (problem and improve over the Patented process.
I have withdrawn concentrated alcohol from near the inter-hose and transported it by re-cycling into the bulk of the organic phase. Also, low concentration alcohol containing organic phase was recycled from bulk to the interfacial region slightly below the above mentioned entry point. This immediately created a higher concentration gradient of the alcohol at the interphase.
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Thus, simultaneously with the re-cycling of alcohol in the organic phase from the near the interphase to the bulk of the organic phase, and from bulk to interfacial region I could automatically obtain faster migration of alcohol from aqueous phase to the organic phase.
The total conversion of glucose to alcohol also increases in the modified process as yeast is able to convert more glucose to alcohol in the aqueous phase since the rate of build up of alcohol in the aqueous phase is more gradual due to faster overall transfer of alcohol from aqueous to organic phase.
That means I am able to control toxicity to yeast due to generally caused by high concentration of alcohol.
Further advantages are obtained by re-cycling bulk of the organic phase to the interfacial region which help in faster rate of mass equalisation within the organic phase.
I have further found that it is also possible to use molasses instead of starch as a source for glucose in the invented process, though, the same could also used in the patented process but not with that much advantage as in this invented process.
The features regarding the handling of the aqueous phase remain the; same as in the earlier patented process. In other words the techniques adopted in the aqueous phase of the earlier Patent were also repeated for the organic phase. In addition to the above to enhance higher rate of transfer of alcohol it was possible to vibrate the fermenting vessel and also add inert floating particles to increase the rate of production. For further details of the function of the particles and vibration, reference is invited to my earlier Patent No.173212.
The invention will now be more fully described with reference to the flow diagrams shown schematically in the figure of the
accompanying drawings.
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Thus according to this invention there is provided process for manufacture of ETHANOL from Glucose which comprises subjecting an aqueous solution of around 10% concentration (wt/vol) of glucose and
fermented above at around 30°C in the presence of yeast followed by separating Ethanol produced at a p.H. of 4-4.5 and wherein the fermentation is carried out in the presence of organic solvent as herein described so as to obtain and aqueous phase containing a product of fermentation and organic phase above the aqueous phase having high purity ethanol obtained from fermentation and wherein the organic phase and the aqueous phase are maintained in the volume ratio of 2:1 to l:1 subjecting the aqueous phase at the lower level of the fermented to recirculate in the following manner:
a) Withdrawing a stream of the aqueous phase from the intermediate
location in the aqueous phase and recirculate same to the aqueous
phase at a level below that of the inter phase of aqueous phase
and organic phase ?
b) Withdraw the stream of aqueous phase from the level immediately
adjacent to inter phase from a location which is above the location
at which the first mentioned recirculated stream is admitted as
mentioned in part (a) above and recirculating the said withdrawn
stream to a lower level in the aqueous phase.
c) Withdrawing the product stream from near the bottom of the
aqueous phase.
d) Subjecting said stream to centrifugation to separate spent
yeast and Useful liquid stream.
e) Recirculate the recovered yeast and subjecting the useful
liquid stream to distillation to obtain ethanol stream (95% pure)
and waste water effluent stream characterized in that the organic phase is
subjected to recirculation in the following manner.
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a) Withdrawing the organic stream containing alcohol from near and above inter-
phase and re-circulate same to the bulk of the organic phase at a higher level.
b) Withdrawing the stream organic phase from the bulk region and re-circulating the
same at near the inter-phase.
c) Withdrawing the product stream from the organic phase at a level substantially
above me inter phase containing high purity alcohol.
d) Subjecting the above stream to distillation to separate the organic solvent and
the alcohol recycling the recovered solvent to the fermentor and recovering as
alcohol final product stream having 100% ethanol.
e) using finely divided inert particles in the aqueous phase in a suspended manner
in order to provide more surface area for conversion of glucose to alcohol by
means of yeast, and
f) the fermentation being subjected to mechanical vibration of the fermentor at its
lower region to keep the inert particles suspended and enhance rate of
fermentation.
Because of this modification it is now possible to use either starch or molasses as source for Glucose.
It will be seen from the flow diagram shown in Fig.1 that a fermentor 1 is used in which fermentation of the required liquid takes place. An aqueous phase 2 is obtained which stays at the lower portion of the fermentor as aqueous phase. An organic solvent is used to extract the acohol produced due to fermentation and this produces an upper organic phase 3. The liquid slightly below the interface is recycled (4) to the aqueous phase. From an intermediate location in the aqueous phase, a stream 7 is withdrawn and partly recycled as stream 6 just below the level of the withdrawal of (4).
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A stream 5 having alcohol is withdrawn from the bottom of the aqueous phase and is pumped to a centrifuge 8. In the centrifuge the spent yeast is separated from the liquid phase having the alcohol. This liquid phase 9 is subjected to distillation in the distillation column 10 to obtain distilled alcohol phase 11 of 95% strength ana a waste water stream 12 which is sent to the effluent treatment plant.
In the earlier Patent, the organic phase containing the alcohol is withdrawn from a suitable location as stream 13 and is subjected to distillation in unit 14 for separation of the solvent and alcohol. The distilled alcohol stream 15 is 1008 pure ethanol. The solvent stream 16 is sent to the fermentor 1 as recycled stream.
In this present modification, the organic phase is also subjected to recycling in a manner similar to the aqueous phase.
Thus it will now be seen that the liquid in organic Phase-3 slightly above the inter phase is recycled to a higher level as stream 4-A. From an intermediate location in this organic phase a stream 6-a just below the level of withdrawal of stream 4-A.
A stream 5A having pure alcohol (99.9%) is withdrawn from the top of the organic phase as stream 13 and the subjected to distillation in unit 14 for separation of solvent and alcohol. The distilled alcohol stream 15 is 100% pure ethanol. The solvent stream 16 is sent to the fermentor 1 as recycled stream.
The invention is explained in further detail in the following example:
EXAMPLE:
2 0 litres of Molasses diluted to 10% fermentable sugar (which is Glucose), specific gravity 1.08 and 2 0 litres solvent, ethyl benzene were subjected to fermentation at around 30°C in presence of yeast for about 2.40 hrs. 87%; conversion of glucose to
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alcohol was achieved. A recirculation of 7.5 lit/hr. of the liquor was maintained from the top of the aqueous layer to the middle layer. Also, rate of withdrawal of liquid from middle to top was 7.5 lt/hr. The amount of total ethanol produced at the end of fermentation was found to be about 0.9568 Kg. of alcohol in 3 hours. This total amount of alcohol was the amount present in the upper organic phase as 100% ethanol and (ii) in the lower aqueous phase as 95% ethanol. The amount of ethanol in the organic phase (2 0 litres) was about 0.426 Kg. The amount of ethanol in the aqueous phase (20 lit) was about .53 kg. I verified the correctness of the amount of ethanol produced from the distribution co-efficient of solvent.
EXAMPLE 2 :
(1) Organic medium used was 20 litres of ethyl benzene and
aqueous phase was also 2 0 litres.
(2) Time of fermentation and extraction was 2 hours.
(3) Inert particles used were hollow concentric open spheres
of teflon.
(4) Recycle rates were 5 litres /hr in both instance (in the
aqueous phase).
(5) Recirculation rates were 2 litre/hr in both instances in
the organic phase.
It was found that the conversion of glucose to ethanol was 90%. The concentration of ethanol in the organic phase was .02126 kg/lit and in the aqueous phase was .02658 kg/lit giving a total yield of 0,4252 kg. in organic phase and 0.5316 kg. in aqueous phase. A total of 0.9568 kg. of ethanol was thus obtained.
EXAMPLE 3 :
(1) Organic medium used was 2 0 litres of ethyl benzene and
aqueous phase was also 2 0 litres.
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(2) Time of fermentation and extraction was one hour and
fifteen minutes at 30°C in presence of yeast.
(3) Inert particles used were hollow concentric open spheres
of teflon.
(4) Stecirculation rates were 5 litres/hour in both instances
in the aqueous phase only.
(5) Recirculation rates were 2 litres/liour in both instances
in the organic phase only.
to was found that the conversion of glucose (using St/Md) to ethanol was 95%. The concentration of ethanol in the organic phase was .0224 kg/lit and in the aqueous phase was .028 kg/lit giving a total yield of .0448 kg in the organic phase and 0.56 kg in the aqueous phase. A total of 1.008 kg. of ethanol was thus obtained.
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Claim:
1) Process for manufacture of Ethanol from Glucose, which comprises subjecting an aqueous solution of around 10% concentration (wt/ vol.) to Glucose by fermentation at around 30°C in the presence of yeast followed by separating Ethanol produced at a p. H of 4 - 4.5 and wherein the fermentation is carried out in the presence of organic solvent as herein described so as to obtain and aqueous phase containing a product of fermentation and organic phase above the aqueous phase having high purity ethanol obtained from fermentation and wherein the organic phase and the aqueous phase are maintained in the volume of 2:1 to 1:1, subjecting the aqueous phase at the lower level of the fermentor to re-circulate in the following manner:
a) withdrawing a stream of the aqueous phase from the intermediate
location in the aqueous phase and re-circulate same to the aqueous
phase at a level below that of the inter phase of aqueous phase and
organic phase.
b) withdraw the stream of aqueous phase from the level immediately
adjacent to inter phase from a location which is above the location at
which the first mentioned re-circulated stream is admitted as mentioned in
part (a) above and re-circulating the said withdrawn stream to a lower
level in the aqueous phase.
c) withdrawing the product stream from near the bottom of the aqueous
pnase.
d) subjecting said stream to centrifugation to separate spent yeast and
useful liquid stream.
e) re-circulate the recovered yeast and subjecting the useful liquid stream to
distillation to obtain ethanol stream (95% pure) and waste water effluent
stream characterized in that the organic phase is subjected to re-
circulation in the following manner

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a) withdrawing the organic stream containing alcohol from near and above
inter-phase and re-circulate same to the bulk of the organic phase at a
higher level.
b) withdrawing the stream organic phase from the bulk region and re-
circulating the same at near the inter-phase.
c) withdrawing the product stream from the organic phase at a level
Substantially above the inter phase containing high purity alcohol.
d) subjecting the above stream to distillation to separate the organic solvent
and the alcohol, recycling the recovered solvent to the fermentor and
Recovering as alcohol as final product stream having 100% ethanol,
e) using finely divided inert particles in the aqueous phase in a suspended
manner in order to provide more surface area for conversion of glucose to
alcohol by means of yeast, and
f) the whole fermentation is subjected to mechanical vibration of the
fermentor at its lower region to keep the inert particles suspended and
Enhance rate of fermentation.
2. A process as claimed in Claim 1 wherein source for glucose is starch or
molasses.

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3. A process for the manufacture of ethanol from glucose, substantially as
herein described.
There is disclosed process for manufacture of Ethanol from Glucose, which comprises subjecting an aqueous solution of around 10% concentration (wt/vol) of glucose by fermentation at around 30°C in the presence of yeast followed by separating Ethanol produced at a P.H. of 4 - 4.5. The fermentation is carried out in the presence of organic solvent as herein described so as to obtain and aqueous phase containing a product of fermentation and organic phase above the aqueous phase having high purity ethanol obtained from fermentation. A suitable conditions for maximum production is also disclosed.

Documents:


Patent Number 201474
Indian Patent Application Number 00203/CAL/2000
PG Journal Number 07/2007
Publication Date 16-Feb-2007
Grant Date 16-Feb-2007
Date of Filing 06-Apr-2000
Name of Patentee DR. AMALESH SIRKAR
Applicant Address 76/A, BONDEL ROAD, 2ND FLOOR, KOLKATA-700019
Inventors:
# Inventor's Name Inventor's Address
1 DR. AMALESH SIRKAR 76/A, BONDEL ROAD, 2ND FLOOR, KOLKATA-700019
PCT International Classification Number C12 P007/06
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA