Environmental Engineering Reference
In-Depth Information
characteristics and wood properties. This hybrid is also amenable to in vitro manipulations includ-
ing genetic transformation.
Recent reviews (Hinchee et al. 2009; Abramson et al. 2010; Harfouche et al. 2011) have
considered genetic engineering of
Eucalyptus
along with other tree crops. Eucalyptus genome
sequencing was also reviewed recently (Grattapaglia and Kirst 2008). Several microsatellite
markers of
Eucalyptus
were developed and characterized by Brondani et al. (1998). Complete
nucleotide sequence of the chloroplast genome from the Tasmanian
E. globulus
was reported
by Steane in 2005. Harcourt et al. (2000) reported development of transgenic
Eucalyptus
. They
used
Agrobacterium
-mediated transformation to transfer insecticidal
cry3A
gene to
E. camaldu-
lensis.
Recently, the forestry biotechnology company has patented transgenic Eucalyptus
hybrid
(
E. grandis
×
E. urophylla
). These freeze-tolerant transgenic plants harbor transcription factor
CBF2
from
Arabidopsis
driven by the
Arabidopsis
rd29a
stress-inducible promoter (Hinchee
et al. 2009). According to a recent report from the Institute of Science in the Society (ISS),
Arborgen's transgenic
Eucalyptus
were modified with genes conferring resistance to antibiotics
and altering the lignin pathway in addition to the CBF transcription factor (http://www.i-sis.org.
uk/FTGEEEASI.php).
3.5 BIodIesel
The diesel engine, made by Dr. Rudolph Diesel, was originally run on peanut oil at the Paris
Exposition of 1900. Various vegetable oils were used to run these first engines, and Dr. Diesel stated
“the diesel engine can be fed with vegetable oils and will help considerably in the development of
the agriculture of the countries which use it” (Demirbas 2008). Transesterification is the process of
making biodiesel from triglycerides (fatty acids). During this process, triglycerides are reacted with
methanol or ethanol in the presence of a catalyst (that speeds up the reaction rate) to produce “bio-
diesel, (m)ethylesters, and glycerin” (Demirbas 2008) (Figure 3.2). Some of the benefits of biodiesel
are availability, renewability, biodegradability, lower exhaust emissions, and it is nonflammable and
nontoxic (Demirbas 2008).
Although the use of biodiesels can help stem the use of foreign oil, the present cost of commercial
production outweighs its benefits, with a gallon of biodiesel (100%) costing from $2.00 to $2.50 plus
taxes (Demirbas 2008). Also, “the competitiveness of biodiesel relies on the prices of biomass feed-
stock and costs, linked to the conversion technology” (Demirbas 2009). When blended with petrol
(up to ~20%), there seems to be no problem incorporating the new fuel in engines or equipment,
and little modification is required with higher percentage blends (Demirbas 2009). Production of
biodiesel can lead to useful by-products that may help reduce the total cost of seed cake, fruit husks,
and glycerin (Achten and Mathijs 2007). The use of vegetable oils is likely an inexhaustible source
of renewable energy with several different sources: cottonseed, rapeseed, sunflower seed, soybean,
jatropha, and palm. In the United States, soybean oil is the primary biodiesel source, palm oil is the
source in Indonesia and Malaysia, rapeseed oil in Europe, and jatropha in India and Southeast Asia
(Demirbas 2008).
3.5.1 B
iodiESEl
p
roduction
m
EthodS
A general process for biodiesel production is represented in Figure 3.2. Various methods of biodiesel
production from different sources were reviewed recently (Andrade et al. 2011). This review described
the transesterification of vegetable oils, animal fats, and oil from algae to produce biodiesel using
homogeneous, heterogeneous, and enzyme catalysts along with ultrasound, microwave, and super-
critical alcohol techniques. Transesterification (base, acid, or enzyme catalyzed) and noncatalytic
transesterification are two general methods used for biodiesel production. During transesterification,
methanol is preferred over the use of ethanol because of its relatively low cost, lower moisture sen-
sitivity, miscibility with biodiesel, and ability to reduce the viscosity of biodiesel (Demirbas 2008).
