Applications of Biotechnology for the Utilization of Renewable Energy Resources - Sustainable Biotechnology: Sources of Renewable Energy - page 4

fermentation conditions. Hence, combined with the economy of scale derived from
large refineries, secondary products could be key to bridging the price gap between
fossil fuels and renewables.
One critical advantage of biofuels is their potential to achieve a reduction in
greenhouse gas releases, since the plants from which they are produced derive their
carbon from the atmosphere. The overall balance of greenhouse gases however,
depends in large measure on the particular feedstocks used and the methods by
which they are produced. Corn ethanol for instance, while being potentially car-
bon neutral, is not likely to achieve an overall reduction in greenhouse gas release
due to its requirement for nitrogenous fertilizer and the associated release of nitrous
oxide [7]. An interesting approach to the production of biodiesel is the use of algae
to synthesize oil from the CO 2 they capture for growth. Algae cultivation offers
a potential low-cost alternative to physical methods of carbon sequestration such
as pumping liquid CO 2 underground or underwater or chemical methods such as
base-mediated capture of CO 2 and subsequent burial of the resulting carbonates.
The algae, while using CO 2 as their sole source of carbon for growth, can produce
up to 50% of their weight in oil suitable for conversion to biodiesel. Algae are one
of the best sources of plentiful biomass on earth; their potential for biosynthesis of
astaxanthin, a red carotenoid nutraceutical responsible for the color of salmon flesh,
was explored in Chapter 13 “Photoautotrophic Production of Astaxanthin by the
Microalga Haematococcus pluvialis ”, Del Rio et al.
In a biological system, the biosynthesis of industrially useful compounds has
long been recommended. Heparin, a low-molecular weight highly sulfated polysac-
charide represents a unique class of natural products, that has long been used as an
anticoagulant drug. Due to recent outbreaks of contamination and seizure of hep-
arin manufacturing facilities [8], an efficient bioconversion process of heparin is
required. In Chapter 14 “Enzymatic Synthesis of Heparin”, Liu and Liu describe
novel enzymatic approaches for the biosynthesis of heparin sulfate that mimic
E. coli heparosan.
Discovering new and sustainable resources can help refuel industrial biotech-
nology. Adverse environmental conditions which normal earth microbiota do not
tolerate, offer potential sites to explore specific sets of microorganisms desig-
nated as “Extremophiles”. The discovery of these microorganisms has enabled the
biotechnology industry to innovate unconventional bioproducts i.e. “Extremolytes”
[9]. In Chapter 15 “Extremophiles: Sustainable Resource of Natural Compounds-
Extremolytes”, Kumar et al. provide an overview of these extreme habitats. The
applications of extremophiles and their products, extremolytes, with their possible
implications for human use are also discussed broadly.
This topic “Sustainable Biotechnology: Sources of Renewable Energy” is a col-
lection of research reports and reviews elucidating several broad-ranging areas of
progress and challenges in the utilization of sustainable resources of renewable
energy, especially in biofuels. This topic comes just at a time when government
and industries are accelerating their efforts in the exploration of alternative energy
resources, with expectations of the establishment of long-term sustainable alter-
natives to petroleum-based liquid fuels. Apart from liquid fuel this topic also