Journal of Sustainable Bioenergy Systems, 2013, 3, 163-170
http://dx.doi.org/10.4236/jsbs.2013.33023 Published Online September 2013 (http://www.scirp.org/journal/jsbs)
Biodiesel from Plant Resources—Sustainable Solution to
Ever Increasing Fuel Oil Demands
Md Enamul Hoque*, Lu Pui Gee
University of Nottingham Malaysia Campus, Jalan Broga, Semenyih, Selangor, Malaysia
Received December 27, 2012; revised January 28, 2013; accepted February 15, 2013
Copyright © 2013 Md Enamul Hoque, Lu Pui Gee. This is an open access article distributed under the Creative Commons Attribu-
tion License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
ABSTRACT
The demand for fuel oil is ever increasing with the advance of the modern world, whereas worldwide reserves of fossil
oils are diminishing at an alarming rate. However, there exist large stockpiles of vegetable oil feedstocks that could be
exploited to produce fuel oil, called biodiesel with the aid of biotechnology. Initially, the biodiesel produced from
vegetable oil did not attract much attention because of its high cost. However, the recent increase in petroleum prices
and the uncertainties of petroleum availability led to the renewal of interest in biodiesel production from such sustain-
able resources (i.e., vegetable oil feedstocks). This research focuses on the production of biodiesel from plant resources,
and further investigates the influences of key process parameters, such as the molar ratio of methanol to oil, catalyst
concentration, reaction temperature, reaction period and stirring speed on the biodiesel yield. This investigation is to
determine the optimum process parameters for maximum biodiesel yield. The biodiesel was produced from three vege-
table oil feedstocks, namely palm, soybean and sunflower oil via a transesterification process. It was observed that all
the process parameters significantly influenced the biodiesel yield. The maximum biodiesel yields for palm, sunflower
and soybean oil feedstocks were found to be 87.5%, 83.6% and 80.2%, respectively at optimum condition. The results
suggest that through proper optimization of the process parameters the biodiesel yields could be maximized. In conclu-
sion, the production of biodiesel from plant resources would be regarded as a sustainable solution to the ever increasing
demand of fuel oils.
Keywords: Sustainable Solution; Fuel Oil; Biodiesel; Plant Reso urce; Biotechn ology; Process Parameter
1. Introduction
Biodiesel (known as fatty acid methyl ester) is a mono-
alkyl ester of long chain fatty acids produced from re-
newable resources such as virgin vegetable oils, waste
vegetable oils, animal fats, algae etc. [1-3]. It is an alter-
native fuel that is used in compression-ignition diesel
engine with slight or no modification, and has attracted
great attention because of its renewability, better gas
emissivity and biodegradability [4]. Biodiesel has a
lower volumetric heating values and higher cetane and
flash points [5]. Biodiesel can be used in the pure form
noted as B100 or as a blend (e.g. 20% biodiesel and 80%
petroleum diesel). The biodiesel has been regarded as the
potential substitute for petroleum diesel as it offers a
number of attractive beneficial properties compared to
conventional petroleum diesel [6]. For example, the use
of biodiesel maintains a balanced carbon dioxide cycle as
it is based on renewable biological materials. Besides,
environmentally friendliness due to reduced emissions
(carbon monoxide, sulphur, aromatic hydrocarbons and
soot particles) during combustion is of another benefit,
while it offers non-toxic and complete biodegradabile
properties. The production of biodiesel from various
sources has been explored by some researchers [7-14].
Direct use of vegetable oil containing high amount of
free fatty acids in diesel engines, can cause oil ring
sticking, lubricating problems, poor fuel atomization or
even prevention of atomization as a result of plugged
orifices, poor cold engine start up, and the creation of
gum and other deposits [15]. Therefore, a special proce-
dure is required to diminish the free fatty acids in the
vegetable oil and thus converts the vegetable oil to bio-
diesel which has similar properties and performances to
that of petroleum diesel. Potential processes for the pro-
duction of biodiesel include microemulsion, pyrolysis
(thermal cracking) and transesterification. Among all
*Corresponding a uthor.
C
opyright © 2013 SciRes. JSBS

M. E. HOQUE, L. P. GEE
164
these, transesterification is considered to be the most
practiced process as it is relatively simple and cost-ef-
fective. Besides, it also tends to lower the viscosity of the
biodiesel and produces glycerol as a by-product which
also has commercial value.
The transesterification is a chemical process that in-
volves a number of consecutive reversible reactions be-
tween the triglyceride segment of vegetable oil and an
alcohol in the presence of a catalyst to produce ester (i.e.
biodiesel) and by-product (i.e . glycerin) [16]. The tri-
glyceride is converted stepwise to diglyceride, mono-
glyceride and finally glycerol, whereby 1 mol of alkyl
ester is removed at each step. The formation of alkyl
ester from monoglyceride is believed to be the step that
determines the reaction rate since monoglyceride is the
most stable intermediate compound [17]. Generally, the
alcohols used in the transesterification process include
methanol, ethanol, propanol and butanol. However,
methanol is widely used because of its cost effectiveness,
and favorable physical and chemical nature (shortest
chain alcohol) [18]. A catalyst is usually used to enhance
the reaction rate and biodiesel conversion. Since the re-
action is reversible, excess alco hol is required to shift the
equilibrium to the product side. Various types of cata-
lysts such as alkali-based, acid-based or enzymatic are
used depending upon the nature of the oil exploited for
the biodiesel production. Alkali-based catalysts include
sodium hydroxide (NaOH), potassium hydroxide (KOH)
etc. Sulfuric acid (H2SO4) and hydrochloric acid (HCI)
are usually used to as acid catalysts, while lipases and
algaes have been tested as enzymatic catalysts [16].
However, the choice of catalyst depends on the free fatty
acids (FFA) content in the feedstock oil. Alkaline-cata-
lyzed transesterification is much faster than acid-cata-
lyzed transesterification and thus most often used [17].
Overall, this study concentrates on the production of
biodiesel from various plant (palm, soybean and sun-
flower oil) feedstocks, and further investigates the influ-
ences of key process parameters, such as the molar ratio
of methanol to oil, catalyst concentration, reaction tem-
perature, reaction period and stirring speed on the bio-
diesel yields.
2. Materials and Methods
2.1. Feedstocks and Reactants
Three types of locally produced (in Malaysia) vegetable
oils were used in the experiments as fundamental feed-
stocks for the production of biodiesel. They were palm
oil (obtained from Yee Lee Edible Oils Private Limited),
soybean oil (obtained from Yee Lee Edible Oils Private
Limited) and sunflower oil (obtained from Econfood
Manufacturing (M) Sdn. Bhd). The analytical-grade
methanol and potassium hydroxide (KOH) provided by
the Chemical Laboratory, University of Nottingham Ma-
laysia Campus were used as the prime reactants.
2.2. Preparation of Potassium Methoxide
The measured KOH was dissolved in methanol within a
conical flask. The conical flask had been swirled for few
minutes until the KOH was fully dissolved in methanol
and hence, the final so lution of potassiu m methox ide was
produced. To prevent the potassium methoxide to be ex-
posed to the air the opening of the conical flask was
wrapped with aluminum foil. Otherwise, the potassium
methoxide may react with air which can lead to the com-
promise of its reaction with methanol and catalyst.
2.3. Transesterification Reaction
The feedstock oil was firstly preheated in a conical flask
for 25 minutes to a preheating temperature (e.g. 55˚C) by
means of a water bath shaker. Potassium methoxid e solu-
tion was then added to the preheated oil in the flask. The
overall solution was heated to the specified temperature
for specified time period with continuous stirring at the
specified speed for the transesterification process to oc-
cur. The transesterification is a chemical process that
involves a series of reversible reactions (Figure 1) be-
tween a triglyceride (fat/oil) and an alcohol thus produc-
ing esters and glycerol [15]. Generally a catalyst is em-
ployed to enhance the reaction rate and ultimately the
biodiesel yield. Because of the reversible nature of the
transesterification reaction an excess amount of alcohol
is required to shift the equilibrium to the product side.
For this experiment, the transesterification reaction (i.e.
biodiesel production) was started with the primarily set
process parameters such as methanol to feedstock molar
ratio of 6:1, catalyst (KOH) concentration of 1.0%, reac-
tion temperature of 65˚C, reaction period of 3 hours and
stirring speed of 130 rpm based on another study [19].
The process parameters were then varied over a range
(methanol to feedstock molar ratios of 3:1, 6:1, 9:1, 12:1
& 15:1; catalyst (KOH) concentrations of 0.50 wt%, 0.75
wt%, 1.0 wt%, 1.25 wt% & 1.50 wt%; reaction tempera-
tures of 55˚C, 60˚C & 65˚C, reaction periods of 1 hr, 2
hrs, 3 hrs & 4 hrs, and stirring speeds of 80 rpm, 100 rpm
& 130 rpm) to investigate the influences of process pa-
Figure 1. Transesterification process that involves a series
of reversible reactions between a triglyceride (fat/oil) and
an alcohol which produces esters and glycerol [15].

M. E. HOQUE, L. P. GEE
165
rameters on the biodiesel yields. Upon completion of the
transesterification reaction at various set parameters, a
mixtur e of biodie se l and glyce rin was pro duced.
2.3.1. Separati o n o f Biodiesel
The hot biodiesel mixture was cooled to room tempera-
ture and allowed to settle overnight or at least for a pe-
riod of 8 hours until the distinct separate layers of bio-
diesel and glycerin were formed. The biodiesel (golden
color) was settled at the top, while the glycerin (dark
brown) was at the bottom. The crude biodiesel separated
from glycerin by means of a pipette, was taken into an-
other con i c al flask for was hing.
2.3.2. Wa s hing of Bi o di esel
The crude biodiesel was washed with distilled water to
remove impurities like, traces of glycerin, methanol or
potassium hydroxide. The traces of glycerin, methanol or
potassium hydroxide were absorbed into the water and
thus the leaving the biodiesel pure. The water absorbing
the impurities turned white murky, which was allowed to
settle for an hour for separation from the biodiesel. The
biodiesel was settled at the top and the water absorbing
impurities was at the bottom. The washing process was
repeated until the water became completely clear. At the
end the pure biodiesel was extracted by means of a pi-
pette and preserved in a conical flask for further evalua-
tion.
3. Results and Discussions
The biodiesel was produced from three vegetable oil
feedstocks, namely palm, soybean and sunflower oil via
transesterification process with a range of various proc-
ess parameters, such as molar ratio of methanol to oil,
catalyst concentration, reaction temperature, reaction
period and stirring speed. The influences of these process
parameters on the biodiesel yields are described and dis-
cussed as below.
3.1. Influence of Methanol to Oil Molar Ratio
In the production of biodiesel from vegetable oils
through transesterification process, the methanol/oil mo-
lar ratio is observed to play significant role. The trans-
esterification is an equilibrium process and is generally
carried out with more alcohol than that required for ac-
tual reaction to shift the equilibrium to the expected
product (i.e. methyl ester) side. It is reported that the
transesterification reaction is inadequate at the metha-
nol/oil molar ratio below 5:1 [20]. Various methanol/oil
molar ratios numerically 3:1, 6:1, 9:1, 12:1 and 15:1
were used to investigate the influence of variation of
methanol/oil molar ratio on the biodiesel yields as pre-
sented in Figure 2. At lower methanol/oil molar ratio
(e.g. 3:1) the biodiesel yields were found to be relatively
lower for all three feedstocks (palm, sunflower and soy-
bean oils). The biod iesel yields at the methanol/oil molar
ratio of 3:1 were found to be 70.8%, 68.4% and 65.6%
for palm, sunflower and soybean oils, respectively. The
biodiesel yields increased with the increase of metha-
nol/oil molar ratio and reached the highest yields at the
molar ratio value of 6:1. The highest biodiesel yields at
the methanol/oil molar ratio of 6:1 were found to be
87.5%, 83.6% and 80.2% for palm, sunflower and soy-
bean oils, respectively. Other studies also suggested the
60
65
70
75
80
85
90
3 : 16 : 19 : 112 : 115 : 1
Methanol t o O il M ol ar Rati o
Y i eld of Bi odi esel (% )
Palm Oil
Sunflower Oi l
Soybean O i l
Figure 2. Influence of methanol/oil molar ratio on biodiesel yields for various feedstock oils, with other parameters constant
(catalyst (KOH) concentration of 1.0%, reaction temperature of 65ºC, reaction period of 3 hours and stirring speed of 130
rpm).

M. E. HOQUE, L. P. GEE
166
optimum molar ratio to be in between 4.8:1 to 6.5:1 for
the maximum biodiesel yields from other feedstock oils
(e.g. animal fat, used cooking oil etc.) [5].
At the molar ratio higher than 6:1 the biodiesel yields
were decreased as observed in Figure 2. For example, at
the molar ratio of 15:1 the biodiesel yields for palm, sun-
flower and soybean oils were 68.8%, 64.4% and 63.3%,
respectively which had been significantly lower than the
highest yields obtained at the molar ratio of 6:1. The de-
cline of biodiesel yields at higher molar ratio than 6:1
could be due to the phenomenon that the excess methanol
deactivated the catalyst, thus reducing its reactivity. The
excess methanol also caused the biodiesel extraction dif-
ficult upon transesterification process by blurring the
separation border between produced biodiesel and glyc-
erin. Therefore, the molar ratio of 6:1 was assigned to be
the optimum for the biodiesel conversion, and thus this
molar ratio (6:1) was kept constant throughout the ex-
periment to evaluate the influences of other parameters
on the biodiesel yields. The biodiesel yields were also
observed to be varied among the feedstock oils even at
the same methanol/oil molar ratio. It could be mainly due
to the differences of free fatty acid (FFA) and water con-
tents in the feedstock oils [13], which caused the catalyst
to react with the oils variably.
3.2. Influence of Catalyst Concentration
(%KOH)
A range of KOH concentrations, numerically 0.5%,
0.75%, 1.00%, 1.25% and 1.50% weights of oils were
used to study the influence of catalyst concentration on
the biodiesel yields. The biodiesel yields against various
catalyst concentrations are presented in Figure 3. The
biodiesel yields significantly increased with the increase
of catalyst concentration, producing the highest yields at
the KOH concentration of 1.0%. The highest biodiesel
yields for palm, sunflower and soybean oils were found
to be 87.5%, 83.6% and 80.2%, respectively. The in-
creased conversion of biodiesel with the increase of
catalyst concentration was believed to be due to the in-
creased solubility of methanol into feedstock oils that
enhanced biodiesel conversion reaction [19]. The highest
yield could be because of maximum ester conversion by
the ample amount of catalyst that rendered optimum
solubility of methanol into feedstock oil.
Lower catalyst concentration (e.g. 0.5% KOH) re-
sulted in lower biodiesel yields, like 57.8%, 53.3% and
49.0% for palm, sunflower and soybean oils, respectively.
It could be due to rather limited biodiesel conversion (i.e.
transesterification) because of less influence of catalyst
on the solubilit y of methanol into feedstock oil. Likewise,
at higher catalyst (i.e. KOH) concentrations (e.g. 1.25%
and 1.50%) than 1.0% the biodiesel yields declined re-
markably due to the formation of fatty acid salts (i.e.
soap) by saponification process [19]. The produced soap
blurred the clear separation of biodiesel from glycerin
and also increased the viscosity of the biodiesel, and thus
lowering the biodiesel yield. Therefore, 1.0% KOH was
considered to be the optimum catalyst concentration and
utilized for further inve stigations.
3.3. Influence of Reaction Temperature
The transesterification reaction was conducted at three
different temperatures (e.g. 55˚C, 60˚C and 65˚C), while
other parameters were maintained constant like, metha-
nol/oil molar ratio of 6:1, catalyst concentration of 1.0%
40
45
50
55
60
65
70
75
80
85
90
0.50% 0.75% 1.00%1.25% 1.50%
Catalyst Conc. (KOH%)
Y i el d of Biodi esel (% )
Palm Oil
Sunflower Oil
Soy bean Oil
Figure 3. Influence of catalyst concentration (%KOH) on biodiesel yields for various feedstock oils, with other parameters
constant (methanol/oil molar ratio of 6:1, reaction temperature of 65˚C, reaction period of 3 hours and stirring speed of 130
pm). r

M. E. HOQUE, L. P. GEE 167
KOH, reaction period of 3 hours and stirring speed of
130 rpm. Although the biodiesel conversion (i.e. trans-
esterification) process can happen at a range of tempera-
tures (e.g. from ambient to a temperature close to the
boiling point of methanol) usually higher temperature
speeds up the reaction rate and shortens the reaction pe-
riod. The maximum reaction temperature was set at 65˚C
with the consideration that the temperature higher than
65˚C might cause burning of methanol. On the other
hand, the minimum temperature of 55˚C was taken into
consideration with the assumption that too low tempera-
ture would slow down the reaction rate and thus increase
the reaction period too long, which might not be techni-
cally favorable.
The overall biodiesel yields for different feedstock oils
at different reaction temperatures are presented in Table
1. The results show that the biodiesel yields for all feed-
stocks significantly increase with the increase of tem-
perature as demonstrated in Figure 4. For example, the
biodiesel yields at the temperatures of 55˚C, 60˚C and
65˚C were found to be 81.38%, 83.24% and 87.5%, re-
spectively for palm oil, 78.31%, 80.17% and 83.6%, re-
spectively for sunflower oil, and 76.07%, 77.93% and
80.2%, respectively for soybean oil. The highest yields of
87.5%, 83.6% and 80.2% were obtained for the palm,
sunflower and soybean oil feedstocks, respectively at
highest reaction temperature of 65˚C. This could be at-
tributed to the phenomenon that the higher temperature
(means higher energy input) increased the collision
among the reacting molecules, which accelerated the
chemical reaction (i.e. transesterification process) and
thus increased the biodiesel yields. However, there had
been variation in highest yield for different feedstock oils
that could be because of the variation in their fatty acid
compositions. Therefore, the reaction temperature of
65˚C was considered as optimal and was maintained for
evaluating other p ar ameter s.
Some other studies also reported the similar findings
that the biodiesel yield was influenced by the reaction
temperature [19,21]. In the investigation of the influence
of temperature on the biodiesel conversion, National
Biodiesel Board [20] observed that the increase of tem-
perature from 30˚C to 50˚C increased the biodiesel yield
by 10%. Canakci and Gerpen reported that the biodiesel
yield had declined at the reaction temperature as high as
70˚C [22]. They argued that too high temperature pro-
moted the saponification reaction that negatively affected
the transesterification pro cess (i.e. biodiesel conversion).
3.4. Influence of Reaction Period
Besides the temperature, reaction period also plays sig-
nificant role in the optimization of biodiesel yield that
allows completion of the biodiesel conversion (i.e. trans-
esterification) reaction. Therefore, the transesterification
reaction was conducted for the periods of 1, 2, 3 and 4
hours maintaining other parameters constant (oil/metha-
nol molar ratio of 6:1, catalyst concentration of 1.0%
weight of oil, reaction temperature of 65˚C and stirring
speed of 130 rpm) to evaluate the influence of reaction
period on the biodiesel yields. The overall biodiesel
yields for different feedstock oils at different reaction
periods are presented in Table 1. The yields were found
to be increased significantly with the increase of reaction
period reaching maximum values at the reaction period
of 3 hours above which the yield values declined as
demonstrated in Figure 5. For example, the reaction pe-
riods of 1, 2, 3 and 4 hrs resulted in the biodiesel yields
of 79.709%, 83.98%, 87.5% and 87.5%, respectively for
palm oil, 76.1%, 80.56%, 83.6% and 81.7%, respectively
for sunflower oil, and 72.61%, 76.03%, 80.2% and
77.7%, respectively for soybean oil. At the reaction pe-
65
70
75
80
85
90
5560 65
Reac t i on Temperat ure (oC)
Biodies el Yields (%)
Palm
Sunflower
Soybean
(˚C)
Figure 4. Influence of reaction temperature on biodiesel yields for various feedstock oils, with other parameters constant
(methanol/oil molar ratio of 6:1, catalyst (KOH) concentration of 1.0%, reaction period of 3 hours and stirring speed of 130
rpm).

M. E. HOQUE, L. P. GEE
168
65
70
75
80
85
90
1234
Reac ti on P eri od (hrs)
B i odi esel Y i el ds (% )
Palm
Sunflower
Soybean
Figure 5. Influence of reaction period on biodiesel yields for various feedstock oils, with other parameters constant (metha-
nol/oil molar ratio of 6:1, catalyst (KOH) concentration of 1.0%, reaction temperature of 65˚C, and stirring speed of 130
rpm).
Table 1. Biodiesel yields at different reaction temperatures
and reactions periods for different fee dstock oils, with other
parameters constant (e.g. methanol to oil molar ratio of 6:1,
catalyst (KOH ) concentration of 1.0%, and stirring speed
of 130 rpm).
Biodiesel Yields at Reaction Temperature of 55˚C
Reaction Period (hr) Palm Oil Sunfl owe r Oil Soybean Oil
1 72.819 70.773 68.727
2 77.376 74.679 71.61
3 81.375 78.306 76.074
4 79.515 74.493 73.377
Biodiesel Yields at Reaction Temperature of 60˚C
Reaction Period (hr) Palm Oil Sunfl owe r Oil Soybean Oil
1 74.679 72.633 70.587
2 79.236 76.539 73.47
3 83.235 80.166 77.934
4 81.375 76.353 74.679
Biodiesel Yields at Reaction Temperature of 65˚C
Reaction Period (hr) Palm Oil Sunfl owe r Oil Soybean Oil
1 79.79 76.1 72.61
2 83.98 80.56 76.03
3 87.5 83.6 80.2
4 85.21 81.7 77.7
riod of 3 hours, the obtained highest yields for the palm,
sunflower and soybean oil feedstocks were 87.5%,
83.6% and 80.2%, respectively. The increase of biodiesel
yield with the increase of reaction period could be asso-
ciated with the molecular structure of the oil, which con-
tains saturated fatty acids. These fatty acids having
higher activation energy require longer period of heating
for reaction to occur/complete. It was believed that at the
reaction period of 3 hours the required activation energy
was achieved giving rise to the equilibrium of the reac-
tion, and thus the biodiesel yield reached maximum value.
The prolonged heating might revert back the transesteri-
fication reaction direction which led to decline the bio-
diesel yield after 3 hours. Other study also reported that
the reaction period had influenced the yield of biodiesel
produced via transesterification process from vegetable
oil feedstocks [23].
3.5. Influence of Stirring Speed
For the chemical reaction to occur, it is important for the
reactants to come into close contact. In the conversion of
biodiesel (i.e. transesterification process), the stirring
speed was considered to be an important factor that
might have influenced the biodiesel yield. The trans-
esterification process was carried out at three different
stirring speeds of 80, 100 and 130 rpm, while other pa-
rameters were made to remain constant (e.g. methanol to
oil molar ratio of 6:1, catalyst concentration of 1.0%,
reaction temperature of 65˚C, and reaction period of 3
hours). The influence of stirring speed on the biodiesel
yield is presented in Figure 6. It was observed that the
biodiesel yields increased as the stirring speed increased
for all three feedstock oils. For example, the biodiesel
yields at the stirr ing speeds of 80, 100 and 130 rpm were
found to be 78.3%, 82.2% and 87.5%, respectively for
palm oil, 75.1%, 79.3% and 83.6%, respectively for sun-
flower oil, and 72.5%, 76.4% and 80.2%, respectively for
soybean oil. Higher yield at increased stirring speed was
believed to be due to the phenomenon that vigorous agi-
tation/stirring enhanced intimate contact/interaction be-
tween the reactant molecules (i.e. oil and KOH), which
thus resulted in increased biodiesel production.

M. E. HOQUE, L. P. GEE 169
65
70
75
80
85
90
80100 130
S t irring Speed (rpm)
Biodiesel Yields (%)
Palm
Sunflower
Soybean
Figure 6. Influence of stirring speed on biodiesel yields for various feedstock oils, with other parameters constant (metha-
nol/oil molar ratio of 6:1, catalyst (KOH) concentration of 1.0%, reaction temperature of 65˚C and reaction period of 3 hrs).
4. Conclusion
Various plant feedstocks (palm, soybean and sunflower
oil) were exploited to successfully produce biodiesel via
transesterification process which is considered to be
more economic in compared to other processes (e.g. su-
percritical methanol, thermal cracking, microemulsion
etc.). Besides the cost effectiveness, transesterification
process allows a wide range of parameters to play with
for the maximization of biodiesel yield and easy recovery
of byproduct glycerin. The process parameters had direct
influence on the biodiesel yields for all three types of
feedstocks. For maximum biodiesel yields, the optimum
parameters were determined to be methanol/oil molar
ratio of 6:1, catalyst (KOH) concentration of 1.0%, reac-
tion temperature of 65˚C, a reaction period of 3 hours
and stirring speed of 130 rpm. At op timum condition, the
maximum biodiesel yields were measured to/be 87.5%,
83.6% and 80.2% of the palm, sunflower and soybean oil
feedstocks, respectively. In conclusion, the vegetable oil
feedstocks hold high potential as renewable plant re-
sources for the production of biodiesel that is to contrib-
ute as a sustainable solution to the ever increasing fuel
oil demands. However, the exploitation of vegetable oil
feedstocks in producing biodiesel may give arise to an-
other concern (e.g. extensive acreage required for suffi-
cient production of oilseed crops etc.), which should be
dealt accordingly.
5. Acknowledgements
The authors would like to thank the Faculty of Engineer-
ing, University of Notting ham Malaysia Campus for pro-
viding the fund to carry out this highly prospective re-
search.
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