FIELD OF THE INVENTION:
This invention relates to a method for the enzymatic transesterification of
vegetable oils.
This invention further relates to a method for the enzymatic
transesterification of oils, in particular edible and non-edible vegetable
oils such as Simaruba oil, rice bran oil, mahwa oil, pongamia oil and
waste fried oil, for the production of biodiesel.
BACKGROUND OF THE INVENTION:
Edible and non-edible oils, particularly vegetable oils have attracted
attention as alternaiive potential renewable source for the petroleum
based diesel fuel due to the diminishing petroleum reserves and
environmental consequences of exhaust gases from diesel engines. The
important advantages of biodiesel include its higher flash point, superior
lubricating properties, higher cetane number and above all biodiesel can
almost completely eliminate lifecycle carbon dioxide emissions.
It has been found that Simaruba, Mahwa, Pongamia, rice bran and waste
fried oils are a rich source of oil. It has been found that Simaruba glauca
plants are a rich. The source of Simaruba oil glauca plants grow native to
tropical regions of the Americas from the southeasternmost United States
(southern Florida) south through Mexico and the Caribbean to Brazil,

Venezuela and southern part of India and are able to ensure a
reasonable production of seeds with very little inputs.
Oil content of Simaruba seed ranges from 40.2-70.5% by weight. The
fatty acid composition of Simaruba oil consists of oleic acid (85%) and
linoleic acid (10%). Mahwa (Mahwa longifolia) and Pongamia (Pongamia
pinnata) are trees thought to have originated in India and is found
throughout Asia.
The trees are well suited to intense heat and sunlight and their dense
network of lateral roots and thick, long taproot make drought them
tolerant and are able to ensure a reasonable production of seeds with
very little inputs.
Rice Bran Oil was traditionally used In Southern India for cooking.
Following decline in usage for last three decades this is gaining
momemtum due to number of increasing restaurants.
Fried oil is the left over oil after food preparation fried oil has attracted
attention as an alternate source biodiesel due to its very high fatty acid
content. To reduce the free fatty acid content, some pretreatment is
required.

The oil content of Pongamia seed ranges from 30 to 50% by weight. The
fatty acid composition of the Pongamia oil consists of oleic acid (71.3%),
linoleic acid (18.3%), eicosenoic acid (12.4%), stearic acid (8.9%) and
palmitic acid (7.9%).
The oil content of Mahwa seed ranges from 30 to 40% by weight. The
fatty acid composition of the Mahwa oil oleic acid (37%), palmitic acid
(24.5%), stearic acid (22.7%), linoleic acid (14.3%) and arachidic acid
(1.5%).
The fatty acid composition of the Rice bran oil consists of oleic acid
(42.50/c) linoleic (39.1%), palmitic acid (15%), stearic acid (1.9%) and
arachidic acid (0.5%).
Composition of waste fried oil consists of oleic acid 24.7%, linoleic acid
55.6% stearic acid 4.74%, palmitic acid 7.5% and other acid 1.4%.
Therefore, it was envisaged to use these oils for the synthesis of biodiesel.
However, chemical methods involve high temperatuee requirements, and
use hazardous chemicals, which cannot be easily disposed off. Further
physiochemical methods of synthesis often lead to poor reaction
selectivity.

Therefore, a need exists In the industry to devise a process for the
synthesis of biodiesel from oils, which has low temperatuee
requirements, is eco-friendly and selective.
OBJECTS OF THE INVENTION
It is an object of this invention to propose a process of the enzymatic
transesterificaiion of oils, which is eco-friendly and cost-effective.
It is a further object of this invention to propose a process of the
enzymatic transesterification of oils, which has low temperatuee
requirements.
Another object of this invention, is to propose a process of the enzymatic
transesterification of oils, which is selective in nature and generates
negligible by products.
These and other objects and advantages of the invention will be apparent
from the ensuing description.
BRIEF DESCRIPTION OF THE INVENTION ACCOMPANYING
DRAWINGS:
Fig. 1 gas chromato gram of Simaruba biodiesel.
Fig 2 gas chromato gram of Pongamia biodiesel.

Fig 3 gas chromato gram of Mahwa biodiesel.
Fig 4 gas chromato gram of Ricebran biodiesel.
Fig 5 gas chromato gram of waste biodiesel.
BRIEF DESCRIPTION OF THE INVENTION -
This invention relates to a process for the enzymatic transesterification of
oils for the production of biodiesel.
In accordance with this invention, a transestrification reaction of the oils
were carried out in a solvent, using an enzyme. The overall
transesterificaiion reaction has been depicted as follows:

The transesterification reaction has been carried out in screw-capped
vials with different methanol to oil molar ratio, solvent to oil volume ratio
with different amount of immobilized lipase. Synthesis of fatty acid
methyl esters has been monitored by gas chromatograph from the
aliquots of transesterification reaction, collected at different time
intervals.

The pretreatment step has been done in case of Pongamia and Waste
fried oils using weak acid followed by water degumming to reduce the
more viscosity of the oils. Phosphoric acid Oxalic acid have been used for
waste fried and Pongamia oils respectively.
The oils used for carrying out the process according to the invention are
Simaruba oil, pongamia oil, mahwa oil, rice bran oil and waste fried oil.
The alcohol used for transesterification reaction is selected from
methanol, ethanol, propanol, butanol.
The solvent used for the process is selected from hexane, petroleum
ether, tri tertiary butano..
The alcohol: oil molar ratio is maintained between 1:1 to 1:10 and the
solvent to oil volume ratio is between 1:0.2 to 1:1.
The enzyme used is immobilized lipase and in a preferred embodiment,
rhizopus oryzae 3562 is used for transesterification. The enzyme is used
in 2 U to 15 U.
The reaction is conducted over 24 to 96 hours. However, an optimal
conversion is achieved in a reaction time of around 36 hours. The
optimal molar conversion is monitored with respect to a fatty acid methyl
ester, such as methyl oleate. The optimal molar conversion with respect
to methyoleate is found to be around 50 to 62% for Simarouba oil, 40 to

55% for pongamma oil, 45 to 58% for Mahwa oil, 35 to 47% for ricebran
oil and 30 to 40% for waste fried oil.
The invention will now be explained in greater detail with the help of the
following non-limiting examples.
Example 1:
The transesterification reaction of simarouba oil was carried out with the
oil to methanol molar ratio of 1:1, hexane to oil volume ratio of 1:0.2 and
enzyme quantity of 10 µ. An optimum molar ratio of 62.23% (with respect
to methyl oleate) was achieved after 36 hours.
Example 2
The transesterification reaction of Pongamia oil was carried out with the
oil to methanol molar ratio of 1:6, hexane to oil volume ratio of 1:0.6 and
an enzyme amount of IOU. An optimum molar ratio of 58.24% (with
respect to methyl oleate) was achieved after 48 hours.
Example 3
The transesterification reaction of Mahwa oil was carried out with the oil
to methanol molar ratio of 1:4, hexane to oil volume ratio 1:0.4 and an
enzyme amount of 12U. An optimum molar ratio of 47.84% (with respect
to methyl oleate) was achieved after 72 hours.

Example 4:
The transesterification reaction of ricebran oil was carried out with the
oil to methanol molar ratio of 1:2, solvent to oil volume ratio of 1:0.8 and
an enzyme amount of SU. An optimum molar ratio of 47.84% (with
respect to methyl oleate) was achieved after 72 hours.
Example 5:
The transesterification reaction of waste fried oil was carried out with the
oil to methanol molar ratio of 1:10, solvent to oil volume ratio of 1:1 and
enzyme amount of 12U. An optimum molar ratio of 40.43% (with respect
to methyl oleate) was achieved after 48 hours.
The fuel properties of biodiesel i.e. viscosity, flash point, pour point and
calorific value have been determined.
The Simaroba biodiesel showed a viscosity of 8.9 (mm2/s), flash point of
IS6°C, pour point of 12°C and a calorific value of 38.6 MJ/Kg. The fuel
properties of Simaroba biodiesel were found to be improved from crude
Simaroba oil which ahs a viscosity of 36 mm2/s and a pour point of
32°C.

The gas chromatography of Simaroba biodiesel 1 has been carried out
and the chromatogram is shown in Fig 1, that of Pongamia oil biodiesel
in Fig 2; Mahwa oil biodiesel in Fig 3; Rice bran oil biodiesel in Fig 4 and
the chromatogram of waste Fried oil is shown in Fig 5.
The properties of the biodiesel are found to be improved from the crude
oils. The enzymatic transesterification of triglycerides is a good
alternative over chemical process due to its eco-friendly, selective native
and low temperatuee requiremen. Because of specificity of enzyme by-
product generation is almost negligible. The biocatalyst is easily
separable from the product ester. The process is very environment
friendly.

WE CLAIM:
1. A process for the preparation of biodiesel from vegetable oils
comprising the step of conducting a transesterificaiion reaction
of the oil with alcohol In a solvent, wherein the
transesterificaiion reaction is carried out in the presence of an
immobilized lipase enzyme.
2. The process as claimed in claim 1, wherein the vegetable oil is
selected from Simarouba oil, Pongamia oil, Mahwa oil, ricebran
oil and waste fried oil.
3. The process as claimed in claim 1, wherein the solvent is
selected from hexane, petroleum ether, tri-tertiary butanol.
4. The process as claimed in claim 1, wherein the alcohol is
selected from methanol, ethanol, propanol, butanol.
5. The process as claimed in claim 1, wherein the lipase enzyme is
Rhizopus oryzae 3562.
6. The process as claimed in claim 1, wherein the alcohol:oil molar
ratio is from 1:1 to 1:10.

7. The process as claimed in claim 1, wherein the solvent to oil
volume ratio is from 1:0.2 to 1:1.
8. The process as claimed in claim 1, wherein the enzyme is used
in 2U to 15 U.
9. The process as claimed in claim 1, wherein the reaction is
conducted over 24 to 96 hours.
10. The process as claimed in claim 1, wherein a step of
pretreatment is carried out for Pongamia oil and waste fried oil.
11. The process as claimed in claim 10, wherein pretreatment is
carried out Pongammia oil by treating with phoshoiic acid
followed by washing with water.
12. The process as claimed in claim 10, wherein pretreatment is
carried out on waste fried oil by treating with oxalic acid
followed by degumming with water.