7.1
Introduction
Today’s world is confronted with a global energy crisis. Adding to this energy crisis
is the planetary emergency of global warming resultant from extensive use of fossil
fuel usage. Declining geological reservoirs and the allied environmental issues have
put the whole world at stake, whereby warranting global efforts for exploring clean
and carbon neutral energy sources. The answer may lie well in our past, i.e. reliance
on biomass as the source of energy. The biomass sources are renewable in nature,
have a wider geographical distribution, and are environmentally benign. But the real
question remains, which biomass we require to satisfy the escalating energy
demand? Although time and again different researchers have rolled up the dice in
favor of plant derived biomass, microbial biomass may have their own story of
credibility. Aquatic Microbial Oxygenic Phototrophs (AMOPs) generally refer to
algae, cyanobacteria, and diatoms. Among all these organisms algae (from here on
microalgae for specificity) have been a topic of intense scientific focus for issues
pertaining to energy crisis, energy security, and sustainable development.
Microalgae have garnered the attention of the scientific community as a biofuel
feedstock (mostly biodiesel, bio-ethanol, pyrolytic bio-oil, and bio-hydrogen). They
are promising biomass species that can serve as feedstock for the forthcoming
biofuel industry. These wondrous microorganisms have been extensively
investigated owing to their numerous salient attributes in comparison to terrestrial
energy crops. Some of the salient prominent features of microalgae in this regard are:
1. The microalgal lipid content can easily be manipulated/adjusted by altering the
respective growth media composition (Meher et al. 2006).
2. They rely exclusively on atmospheric carbon dioxide as the carbon source for
their growth (Schenk et al. 2008).
3. The microalgal biomass doubling time during logarithmic phase may be normally as little as 3.5 h (Chisti 2007).
4. It is quite feasible to culture microalgae in waste as well as salty water (Schenk
et al. 2008).
5. The intrinsic oil content in many species of microalgae exceeds 80% (by weight
of dry biomass) (Chisti 2007).
6. Algae generally have superior rates of oil and biomass production when compared to conventional crops. This may be assigned to their simple cellular
structure (Becker 1994).
7. Biomass from microalgae can be harvested almost all throughout the year (in
batches). This ensures a consistent and incessant supply of oil (Schenk et al.
2008).
8. Various species of microalgae have been reported to produce different types of
lipids, various complex oils and hydrocarbons (Metzger and Largeau 2005),
which is much conducive in various biomass conversion processes.
9. It is possible to combine algal biofuel production with flue gas carbon dioxide
alleviation, treatment of waste water, and subsequent production of high value
bio-actives (Demirbas 2010).
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M. M. Phukan et al.
Introduction
Today’s world is confronted with a global energy crisis. Adding to this energy crisis
is the planetary emergency of global warming resultant from extensive use of fossil
fuel usage. Declining geological reservoirs and the allied environmental issues have
put the whole world at stake, whereby warranting global efforts for exploring clean
and carbon neutral energy sources. The answer may lie well in our past, i.e. reliance
on biomass as the source of energy. The biomass sources are renewable in nature,
have a wider geographical distribution, and are environmentally benign. But the real
question remains, which biomass we require to satisfy the escalating energy
demand? Although time and again different researchers have rolled up the dice in
favor of plant derived biomass, microbial biomass may have their own story of
credibility. Aquatic Microbial Oxygenic Phototrophs (AMOPs) generally refer to
algae, cyanobacteria, and diatoms. Among all these organisms algae (from here on
microalgae for specificity) have been a topic of intense scientific focus for issues
pertaining to energy crisis, energy security, and sustainable development.
Microalgae have garnered the attention of the scientific community as a biofuel
feedstock (mostly biodiesel, bio-ethanol, pyrolytic bio-oil, and bio-hydrogen). They
are promising biomass species that can serve as feedstock for the forthcoming
biofuel industry. These wondrous microorganisms have been extensively
investigated owing to their numerous salient attributes in comparison to terrestrial
energy crops. Some of the salient prominent features of microalgae in this regard are:
1. The microalgal lipid content can easily be manipulated/adjusted by altering the
respective growth media composition (Meher et al. 2006).
2. They rely exclusively on atmospheric carbon dioxide as the carbon source for
their growth (Schenk et al. 2008).
3. The microalgal biomass doubling time during logarithmic phase may be normally as little as 3.5 h (Chisti 2007).
4. It is quite feasible to culture microalgae in waste as well as salty water (Schenk
et al. 2008).
5. The intrinsic oil content in many species of microalgae exceeds 80% (by weight
of dry biomass) (Chisti 2007).
6. Algae generally have superior rates of oil and biomass production when compared to conventional crops. This may be assigned to their simple cellular
structure (Becker 1994).
7. Biomass from microalgae can be harvested almost all throughout the year (in
batches). This ensures a consistent and incessant supply of oil (Schenk et al.
2008).
8. Various species of microalgae have been reported to produce different types of
lipids, various complex oils and hydrocarbons (Metzger and Largeau 2005),
which is much conducive in various biomass conversion processes.
9. It is possible to combine algal biofuel production with flue gas carbon dioxide
alleviation, treatment of waste water, and subsequent production of high value
bio-actives (Demirbas 2010).
136
M. M. Phukan et al.