Erudite Journal of Biotechnology (EJB), Vol. 1(1), pp. 1-9, November 2012
www.eruditejournals.org/ejb
© 2012 Erudite Journals Publishers
Accepted 29th October 2012
Full Length Research Paper
Assessment for the higher production of biodiesel from
Scenedesmus dimorphus algal species
Gulab Chand Shah*, Mahavir Yadav and Archana Tiwari
School of Biotechnology, Rajiv Gandhi Proudyogiki Vishwavidyalaya, Bhopal, Madhya Pradesh, University of
Technology of Madhya Pradesh, Airport Bypass Road, Gandhi Nagar, Bhopal-462 033, India. *Corresponding author.
Email: gulab777@gmail.com.
Abstract
Algae are the fastest-growing plants in the world, this study demonstrates the production of algal biodiesel
from Scenedesmus dimorphus, biodiesel is an alternative fuel for conventional diesel that is made from natural
plant oils, animal fats, and waste cooking oils. This paper discusses the economics of producing biodiesel fuel
from algae grown in open ponds. Microalgae have been identified as a potential biodiesel feedstock due to their
high lipid productivity and the process conditions are milder than those required for pyrolysis and prevent the
formation of by-products. Algae are very important as a biomass source. Algae will someday be competitive as
a source for biofuel. Algae can be grown almost anywhere, even on sewage or salt water, and does not require
fertile land or food crops, and processing requires less energy than the algae provides. Algae can be a
replacement for oil based fuels, one that is more effective and has no disadvantages. About 50% of their weight
is oil. This lipid oil can be used to make biodiesel for cars, trucks, and airplanes. Microalgae have much faster
growth-rates than terrestrial crops.
Key words: Microalgae, biofuels, lipid, biomass, glycerol, transesterification.
Abbreviation: ASTM, American Society of Testing Materials; FAME, fatty acid alkyl ester; TAGs, try acyl glycerol’s; MFC, microbial
fuel cell; MAO, microalgae oil; TG, triglycerides; PAHs, polycyclic aromatic hydrocarbons.
INTRODUCTION
The search for sustainable and renewable fuels is
becoming increasingly important as a direct result of
climate change and rising fossil-fuel prices. Commercial
production of biodiesel or fatty acid methyl ester (FAME)
involves
alkaline-catalyzed
transesterification
of
triglycerides found in oleaginous food crops with
methanol (Ronald et al., 2012). Biodiesel is produced
from triglycerides derived mainly from vegetable oils or
animal fats. Recently, new oil production methods have
been investigated such as oil produced from algae and
oleaginous yeasts indicating new sources of biodiesel
which, contrary to energy crops, do not conflict with the
cultivation of land for food; therefore they can offer
alternatives to the food vs. fuels land use (Anestis et al.,
2011).
Petroleum-based fuels are recognized as unsustainable
Erudite J. Biotechnol.,
2
Conventional production methods
The direct use of vegetable oils as biodiesel is possible
only by blending them with conventional diesel fuel in a
suitable ratio, but the direct usage of vegetable oils in
diesel engines is not technically possible because of
their: (i) high viscosity; (ii) low stability against oxidation,
and (iii) low volatility (Robles et al., 2009).
Sources of biodiesel and advantages of biodiesel as
diesel fuel
Figure 1. Overview of biodiesel production.
energy source due to their depleting supplies and
contribution to global warming. Renewable biofuels are
promising alternatives to petroleum-based fuels, among
which biodiesel has attracted the most attention in
recent years (Jin et al., 2010). Competitive liquid biofuels
from various biomass materials by chemically and
biochemically have been found promising methods for
near future. There are two global liquid transportation
biofuels: bioethanol and biodiesel, respectively (Fatih,
2011).
Cost and
process
environmental
impact
of
conversion
For a sustainable future of the planet, we must look into
renewable energy sources which implicitly include
sustainable fuel sources. Based on the positive energy
balance or life cycle analysis, biodiesel is shown to be
sustainable (Jidon and Naoko, 2010).
We highlight the important aspects of the biodiesel
which will strengthen the prospect as the next generation
green fuel. Four major areas are discussed: (i) cost and
environmental impact of conversion processes; (ii) efforts
towards environmentally benign and cleaner emissions;
(iii) diversification of products derived from biodiesel
glycerol; and (iv) policy and government incentives (Pinzi
et al., 2009).
Flow diagram of microalgal oil description
High acidic value of MAO makes them an inconvenient
raw material for the traditional biodiesel production.
However, by means of a sequential acidic/basic
transesterification, coupled with a heat integration
strategy, the opportunities of accepting microalgae oil as
a biodiesel precursor will increase (Sánchez et al.,
2011) (Figure 1).
There are more than 350 oil-bearing crops identified,
among which only soybean, palm, sunflower, safflower,
cottonseed, rape seed and peanut oils are considered as
potential alternative fuels for diesel engines (Ayhan,
2007). The advantages of biodiesel as diesel fuel are
liquid nature portability, ready availability, renewability,
higher combustion efficiency, lower sulfur and aromatic
content
higher
cetane
number
and
higher
biodegradability (Ma and Hanna, 1999).
Availability and renewability of biodiesel
Biodiesel is the only alternative fuel so that low
concentration
biodiesel–diesel
blends
run
on
conventional unmodified engines. It can be stored
anywhere where petroleum diesel fuel is stored. Biodiesel
can be made from domestically produced, renewable
oilseed crops such as soybean, rapeseed and sunflower
(Mittelbach and Remschmidt, 2004).
Lower
emissions
by
using
biodiesel
disadvantages of biodiesel as diesel fuel
and
Combustion of biodiesel alone provides over a 90%
reduction in total unburned hydrocarbons (HC), and a
75–90% reduction in polycyclic aromatic hydrocarbons
(PAHs) (Laforgia and Ardito, 1994).
Major disadvantages of biodiesel are higher viscosity,
lower energy content, higher cloud point and pour point,
higher nitrogen oxides emissions, lower engine speed
and power and injector cooking (Prakash, 1998).
Biodiesel economy and algal strain and culture
conditions
Economic advantages of biodiesel can be listed as
follows: it reduces green house gas emissions, it helps to
reduce a country’ s reliance on crude oil imports and
supports agriculture by providing a new labor and market
opportunities for domestic crops (Palz et al., 2002). H.
pluvialis samples were collected from rainwater in Bahía
Blanca Buenos Aires Province, Argentina. Uni-algal
cultures were obtained by means of serial dilutions.
Biflagellate cells were cultured in Bold’s Basal Medium,
containing 3.4 mM of sodium nitrate. The cells were kept
at 24°C (Stein, 1973).
Gulab et al.
3
Table 1. Composition of modified CHU 13 medium.
S/N
1
2
3
4
5
6
7
8
9
10
11
12
13
Composition
KNO3
K2HPO4
MgSO4 hepthydrate
CaCl2
Ferric citrate
Citric acid
CoCl2 dihydrate
H3BO3
MnCl2 tetrahydrate
ZnSO4 hepthydrate
CuSO4 pentahydrate
NaMoO4
0.72N H2SO4
Stock Media 20X (g/L)
8
1.6
4
2.14
0.4
2
2.14
114.4
73.4
8.8
3.2
1.68
Acceptability of microalgal biodiesel and improving
economics of microalgal biodiesel
Microalgal biodiesel will need to comply with existing
standards in the United States the relevant standard is
the ASTM Biodiesel Standard D 6751 (Knothe, 2006).
Cost of producing microalgal biodiesel can be reduced
substantially by using a biorefinery based production
strategy, improving cap abilities of microalgae through
genetic engineering and advances in engineering of
photobioreactors (Sánchez et al., 2003).
Enhancing algal biology and biorefinery based
production strategy
Genetic modification of microalgae has received little
attention. Molecular level engineering can be used to
potentially: (1) increase photosynthetic efficiency to
enable increased biomass yield on light; (2) enhance
biomass growth rate; (3) increase oil content in biomass;
(4) improve temperature tolerance to reduce the expense
of cooling (León-Bañares et al., 2004). Like a petroleum
refinery, a biorefinery uses every component of the
biomass raw material to produce use-able products.
Because all components of the biomass are used, the
overall cost of producing any given product is lowered
(Mata-Alvarez et al., 2000).
MATERIALS AND METHODS
Sample collection and media preparation
Microalgal species ware collected from the upper Lake,
Bhopal, Madhya Pradesh, India. Lake water used for
media preparation came from upper Lake and was stored
in 20 L bottle in the dark to prevent algal growth. The
Lake water was filtered twice before use through triple
thickness whatman filter paper followed by 0.45 µm
Working media 1X (mg/L)
400
80
200
107
20
100
107
5.72
3.67
0.44
0.16
0.084
1 drop
whatman membrane filter. The filtered Lake water was
then stored at 4°C in container in the dark. Lake/sand mix
soil was used for preparing soil extract. The soil extract
was prepared using the method by sifting dry soil once
through a coarse sieve (1 mm) and twice through a 500
µm sieve. One kilogram of the soil was then mixed into 2
L of deionized water. The mixture was filtered through
triple thickness Whatman No.1 filter paper, autoclaved for
20 min at 121°C, 103 kPa and cooled overnight. It was
then centrifuged at 1008 g for 5 min in the 50 ml
polyethylene tubes at room temperature. The supernatant
was poured into 100 mL reagent bottles, and autoclaved
for 20 min at 121°C, 103.35 kPa. Once the bottles were
cool, they were sealed with parafilm and stored at 4°C,
the volume was brought up to 1000 mL in de-ionized
water pH to 7.5 and then autoclaved (Table 1).
Algal culture and measuring algae concentration
through spectrophotometry
Using the proper protocol insure that the algal culture is
clean and not contaminated by protozoan and bacteria.
Stock culture of all species was maintained 100 ml
culture media in 250 ml conical flask and was sub culture
every 14 days. They were grown at constant temperature
growth room or cabinets under an irradiation provided by
a combination of cool white and lights and a 14:10 day
night period. Take out 1 ml of this medium and mix it with
9 ml of this fresh sterile liquid medium, then have 100
microalgae in or 10 microalgae/ml, add 1 ml of this
suspension to another 9 ml of fresh sterile liquid medium,
each ml would now contain a single microalgae. If this
tube shows any microbial growth, there is a very high
probability that this growth has resulted from the
introduction of a single microorganism in the medium and
represents the pure culture of those microalgae. Use of
this pure culture of microalgae for optimization of growth
condition and growth media (Table 2).The scanning
range is 200-70 nm, within the visible spectrum. Most
Erudite J. Biotechnol.
4
Table 2. The different media and condition for algal growth.
S/N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Sign
CDW
CDT
CDR
CLW
CLT
CLR
SDW
SDT
SDR
SLW
SLT
SLR
MW
MT
MR
DW
DT
DR
LW
LT
LR
Media ingredients
CHU medium + deionised water
CHU medium+ deionised water
CHU medium + deionised water
CHU medium + Lake water
CHU medium + Lake water
CHU medium + Lake water
Lake soil + deionised water
Lake soil + deionised water
Lake soil + deionised water
Lake soil + Lake water
Lake soil + Lake water
Lake soil + Lake water
CHU medium + Lake soil + Lake water (mixed)
CHU medium + Lake soil + Lake water
CHU medium + Lake soil + Lake water
Deionised water
Deionised water
Deionised water
Lake water
Lake water
Lake water
culture peak at 670-705 nm because absorbance is
directly proportional to concentration when only the algae
significantly absorb the appropriate wavelength, a
protocol can be made by establishing a linear fit of
standard dilution. After the appropriate wave length is
identified, concentrations of the starting sample are
measure and serial dilutions prepares from that sample.
Because the concentrations have been measured and
then calculated for the serial dilutions, the absorbance of
each dilution is plotted against its concentration.
Therefore, the linear curve fit is a plot of concentration vs.
absorbance at the appropriate wavelength.
Measurement of dry biomass and scale up of algal
culture
The total biomass as, total dry weight, was determined as
follow: whatman (2.5 cm) filter ware washed in deionized
water and dried in a 70°C oven for 24 h and stored in a
vacuum desiccator over silica gel until needed. The filter
ware then weighed to 4 decimal places on an analytical
balance. Ten milliliters of algal culture was filtered until
the filters were dry using a Millipore filtration apparatus.
The filter was then washed with 10mL of 0.65 M
ammonium format solution to remove excess salt and
dried at 90°C for 4 h and placed in vacuum desiccator
over night. Filter was then weighed to four decimal
places. Dry weight was calculated as g/L after subtracting
the filter weight from filter total weight of sample.
Sequencing algal culture vessels is as follows: (a)
innovate culture (test tube) house incoming culture of
algal species. Replicate them for backups. Use them only
Place
Window
Tissue culture lab
Roof
Window
Tissue culture lab
Roof
Window
Tissue culture lab
Roof
Window
Tissue culture lab
Roof
Window
Tissue culture lab
Roof
Window
Tissue culture lab
Roof
Window
Tissue culture lab
Roof
in event an algae culture become contaminated; (b) stock
cultures (125 ml flasks) are maintained aseptically and
use to inoculate starter and to restart stock cultures, and
starter cultures (1000 or 2000 ml flasks) are used to
inoculate carboys; (c) carboys (5-gallons) are used to
inoculate kalwalls, and Kalwalls (60-5 gallons) are used
for large culture quantities of algae; (d) open tanks are
used to culture algae in very large quantities. Select stock
culture of MT (CHU medium + Lake soil + Lake water) of
250 ml flasks and then inoculate into sterilized 1000 or
2000 ml flasks with CHU medium, Lake soil and sterile
water media for starter algal culture production. Select
starter cultures (1 L/ 2 L flasks) and then transfer into
prepared 5-gallon carboy with CHU medium, Lake soil
and sterile Lake water media for large scale algal
biomass production.
Growth parameter and harvest algal biomass
Temperature- 26°C, pH- 7.8, day/night period-14:10,
aeration- continuous and algal culture - 27.6 L. Algae can
be harvested from 5-gallon carboy culture by the addition
of 0.2% ferric chloride in the algal culture and after the
addition of the chemical flocculants algae settled down in
the bottom of the 5-gallon carboy. Settled biomass
removes out from the container and then dries in the
oven for 2 days at 55°C. Dry algal biomass is used
further in oil extraction.
Lipid determination and oil extraction
Ten milliliters of algal culture was filtered using whatman
Gulab et al.
2.5 cm filters, rinsed with isotonic 0.65 M ammonium
format solution and stored at -20°C for later lipid
extraction. Before extraction the filters ware thawed at
room temperature, then homogenized in a glass mortar
with 5 mL of methanol: chloroform: deionised water
(2:1:0.8 v:v:v).the extracts were then transferred to 10 mL
glass stopper centrifuged tubes and centrifuged at 1008 g
for 10 min at room temperature. The supernatant was
then carefully transferred to glass stopper graduated
glass centrifuge tubes. The extract was made up to 5.7
mL with fresh methanol: chloroform: deionised water and
1.5 mL of chloroform was added, followed by 1.5 mL of
deionised water and stirred. After partial phase
separation had occurred. The green chloroform bottom
layer was transferred to dry, pre-weighed 4 mL glass vial
over KOH pellets overnight in vacuum desiccators
weighing. Total lipid content was then calculated as g/L.
The simplest method is mechanical crushing.
Determination of fatty acid concentration
Prepare solvent mixture (95% ethanol/ diethyl ether,1/1,
v/v) 0.1 M KOH in ethanol and 1% phenolphthalein in
95% ethanol. Weigh 0.5 g of oil in conical flask and
dissolve in at least 50 mL of solvent mixture. Titrate, with
shaking, with the KOH solution (in a 25 ml burette in 0.1
ml) to the end point of the indicator (5 drops of indicator),
the pink color persisting for at least 10 s, the acid value is
calculated by the formula: 56.1 x N x V/M where V is the
number of KOH solution used and N its exact normality,
M is the mass in g of sample.
Chemical and enzyme catalyzed transesterification
In a 150 mL Erlenmeyer flask with a magnetic stir bar
placed 0.25 g of anhydrous sodium hydroxide and
dissolved it with 10 mL of methanol. The mixture was
stirred until all of the sodium hydroxide was dissolved. In
a 250 mL beaker placed 5mL of algal oil. The oil was
heated to 60°C. Added 2 ml of the dissolved sodium
hydroxide into the heated oil, immediate the mixture
become cloudy. Allow to stir for 30 min on high. Transfer
content of beaker into a 250 mL separatory funnel. Allow
the mixture to separate for overnight. Transfer the
glycerol (bottom layer) into a beaker from biodiesel. Algal
oil (0.25 g) and acyl accepter (methanol, ethanol,
propanol-2, n-butanol) were taken in the ratio of 1:4 in a
screw-capped veil. To this mixture, 5 ml of enzyme
preparation (crude) was added and incubate at 40°C with
constant shaking at 200 rpm. Progress of the reaction
was monitored by removing aliquots (20 µL) at various
time intervals (4, 8…24 h). The aliquots ware
appropriately diluted (with hexane) and analysis by thinlayer chromatography.
5
Effect of varied amount of enzyme of enzyme on
transesterification
Algal oil (0.25 g) and acyl acceptor (methanol, ethanol,
propanol-2, and n-butanol) were taken in the ratio of 1:4
in a screw-capped vial. The crude enzymes were
prepared by adding of 20 mM sodium phosphate buffer,
pH 7.8 and take this crude lipase solution in varying
amount viz, 1, 2, 3, 4, and 5mL. To the reaction mixture,
these enzyme preparations were added and incubate at
40°C with constant shaking at 200 rpm for 24 h. The
aliquots were appropriately diluted (with hexane) and
analysis by thin-layer chromatography.
Effect of varied
transesterification
amount of
acyl
acceptor on
Algal oil (0.25 g) and acyl acceptor (methanol, ethanol,
propanol-2, and n-butanol) were taken in the different
ratio such as 1:1,1:2,1:3,1:4,1:5, in screw capped veil and
in this mixture 5 mL of prepared crude lipase enzyme
preparation was added. The reaction mixture was
incubated at 40°C with constant shaking at 200 rpm for
24 h. The aliquots were appropriately diluted (with
hexane) and analysis by gas thin-layer chromatography.
Qualitative analysis of
chromatography
esters of
by thin-layer
The formation of ethyl ester of algal oil in the reaction
mixture was also analyzed by thin- layer chromatography
with silica gel 60F254. The solvent system consisted of
hexane/ethyl acetate acetic acid in the ratio of 90:10:1.
The spot ware detected in the UV light.
The quantitave analysis of ester by titration
Prepare solvent mixture 95%ethanol/diethyl ether, 1/1,
v/v, 0.1 M KOH in ethanol and 1% phenolphthalein in
95% ethanol. Total reaction mixture in conical flask and
dissolve in at least 50mL of the solvent mixture. Titrate,
with shaking, with the KOH solution (in a 25 ml burette in
0.1 ml) to the end point of the indicator (5 drops of
indicator) the pink colour persisting for at least 10s. the
acid value is calculated by the formula: 56.1 x N x V/M
where V is the number of ml of KOH solution used and N
his exact normality, M is the mass in g of the sample.
RESULTS AND DISCUSSION
Optimization of algal culture
Although micro algae, especially Scenedesmus dimorphus
Erudite J. Biotechnol.,
Table 3. factor influencing algal growth.
A biotic factors
Light (quantity, quality)
Temperature
Nutrient requirement
O2 and CO2
Salinity
pH
Toxic chemicals
Biotic factor
Pathogens (bacteria, fungi, viruses)
Competition by other algae
Operational factor
Shear produced by mixing
Dilution rate
Depth
Harvest frequency
Figure 2. Optimization of algal culture.
6
is widely distributed in the upper Lake, but these are not
currently used for biotechnological applications. Micro
algal cultures are the same as other microbial culture with
the exception of the light requirement in autotrophic. For
successful micro algal culture, a suitable S. dimorphus
must be selected mainly based on general physical
chemical and biological characteristics together with the
growth optimization of selected species on a CHU13
medium. High cell density mass production culture was
unattainable due to a number of physical, chemical and
biological factors. These factors were summarized in
Table 3. In this study, microalgae were screened for high
dry biomass production. Table 4 shows that all the
different conditions and media composition produced
algal biomass with varying amount. The most one
productive was CHU medium + Lake soil + Lake water
media used for micro algae culture incubate at
department roof followed by CHU medium + Lake soil +
Lake water media at department window therefore CHU
medium + Lake soil + Lake water for micro algae culture
incubate at tissue culture lab. Temperature light and
nutrient media composition may represent the main
limitation for high biomass production rates for the
outdoor and indoor cultivation of microalgae. The
response of selected species of microalgae such as S.
dimorphus to varying nutrient media composition is also
an important consideration when considering the culture
of these algae in closed cultivation system in tissue
culture laboratory. Although the effect of temperature light
nutrient media composition on the growth rate of
laboratory microalgal culture was well but its effect in
outdoor cultures was not properly grown due to the high
temperature in the day time period in Figure 2. An
outdoor (roof) algal culture under goes a diurnal cycle
which, in areas out of the tropics, may show a different of
cell component in summer seasons, the maximum day
temperature of over 41°C temperatures can be an
important limiting factors. When nutrient and temperature
was not limiting the growth of microalgae, light availability
to the average cell becomes the dominant limiting factor
has demonstrated a decrease in the growth rate of micro
algae, with an increase in self shading due to increased
cell density.
Biodiesel production by chemical-catalyzed and by
lipase-catalyzed transesterification
Figure 3. Different steps for algal oil extraction.
Biodiesel was prepared in the form of methyl ester of fatty
acid form algae in oil using chemical catalyzed
transesterification reaction. Figure 4 shows the top layer
in the separation funnel is the biodiesel product and lower
layer is glycerine. The lipase from S. dimorphus source
(which ware prepared crude in laboratory) ware screened
for transesterification. Figure 5 shows lipase from S.
dimorphus is capable of transesterification with (Table 5)
methanol, ethanol and propanol-2 showed by tube 1, 2
and 3, respectively, in which biodiesel (methanol ester,
Gulab et al.
7
Table 4. Algal dry biomass g/L production at different condition and media.
Media composition
CHU medium + deionised water
CHU medium + Lake water
Lake soil+ deionised water
Lake water + Lake soil
CHU medium + Lake water + Lake soil
Lake water
Deionised water
Department window
2.2
3.9
2.3
4.3
5.2
3.7
0.11
Algal dry biomass (g/L)
Department roof Department culture lab
1.6
2
2.7
3.3
1.7
1.9
3.6
3.5
4.9
4.8
2.9
2.1
0.08
0.03
Figure 6. TLC analysis of the methyl ester. TLC analysis of
reaction mixture during transesterification reaction.
Figure 4. The chemical catalyzed trans-esterification reaction
Upper layer is biodiesel and lower layer is glycerine.
Figure 7. TLC analysis of different ester.
Time (h)
Figure 5. Graph shows the effect of incubation time on
biodiesel production at 40°C using 5 ml Scenedesmus
dimorphus.
ethanol ester and propanool-2ester) mix with algal oil in
the upper layer and total reaction mixture in the lower
layer. The n-butanol does not transesterification into nbutanol ester which shows in TLC analysis (lane 4 in
Figure 7) but in tube 4 after lipase – catalyzed
transestrification with algal oil observed a light green
Erudite J. Biotechnol.
8
Table 5. Yield biodiesel production (%) by different acyl acceptor at
different time interval.
Time Interval (h)
4
8
12
16
20
24
Methanol
6
14
33
40
43
44
Ethanol
0
0
4
10
12
12
Propanol-2
0
5
8
19
22
22
a-Butanol
0
0
0
0
0
0
Table 6. Yield of biodiesel production (%) by different acyl acceptor with different
amount of enzyme.
Crude lipase enzyme (ml )
1
2
3
4
5
Methanol
15
16
21
43
44
Ethanol
0
0
0
9
12
Propanol-2
0
3
8
18
22
n-Butanol
0
0
0
0
0
Table 7. Yield of biodiesel production (%)by different acyl acceptor
with different molar ratio of algal oil: acyl acceptor.
Time interval (h)
1
2
3
4
5
Methanol
12
18
37
44
44
coloured layer which might be algal oil. This suggested
that when the number of carbon atom increased in
alcohol from 1 (methanol) to 4 (n-butanol). That increases
dissolving effect of substrate (algal oil) into alcohol. The
lipase from S. dimorphus source (which were prepared
crude in laboratory) ware screened for transesterification.
Figure 5 shows that from S. dimorphus is capable of
transestrification. With this enzyme a yield of 44, 24, 22
and 0%, respectively, for the methyl ester, ethyl ester,
propanyl ester and butanyl ester could be obtained after
24 h (Table 6). The reaction could be qualitatively
followed by TLC (Figures 6 and 7) and quantitatively by
titration (Figure 5). The formation of biodiesel did
increase beyond 24 h which is likely to be inactivation of
the lipase by substrate methanol. The inactivation of
lipase during transesterification reactions has also been
observed by other.
CONCLUSION
As demonstrated hear, micro-algal biofuels is technically
feasible. It is the only renewable biofuels that can
Ethanol
0
3
7
12
10
Propanol-2
5
9
15
22
21
n-Butanol
0
0
0
0
0
potentially completely relocate liquid fuels derived from
gasoline. Financial side of producing algal biofuels needs
to recover significantly to be possible. To produce lowcost micro algal biofuels require primarily improvements
to micro- algal biology through genetic engineering. Use
of the biorefinery idea and advances in photo bioreactors
engineering further lowered the cost of fabrication. In
view of their much greater yield than raceways, tubular
photo bioreactors are likely to be used in producing much
of the algal biomass required for making biodiesel. Photo
bioreactors provide a prohibited environment that can be
modified to the specific stress of highly productive
microalgae to attain a consistently good annual give up of
algal oil.
Algal-biodiesel creation can be done through the use of
chemical (acid, base). There is a recent attention in using
powerless lipase or immobilized whole cells as “green”
alternatives to chemical catalysts to produce biofuels
industrially. However, the cost of the final enzymatic
product remains a difficulty compared to the cheaper
substitute of using chemical catalysis. Using the
apparatus of recombinant DNA technology, it is possible
to increase the supply of appropriate lipases for biofuels
Gulab et al.
fabrication. Protein engineering and site-directed
mutagenesis may be used to alter the enzyme-substrate
specificity, stereo specificity, and thermo stability, or to
increase their catalytic efficiency, which will benefit
biofuels construction, and lower the cost of the generally
process.
Indeed, a thermo stable and more research efforts
should be focused in modifying and cloning more lipases.
Lipases can be immobilized to increase their prepared
stability, making reuse several times possible, and the
alcohol sis process cost-effectively reasonable and
spirited with straight processes.
ACKNOWLEDGEMENT
The authors thank all faculty members of Rajiv Gandhi
Proudyogiki Vishwavidiyalya for their support.
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