their ability to fix atmospheric nitrogen and other positive effects for plants and soil
(Malik et al. 2001). Cyanobacterial species like Tolypothrix, Anabaena, Nostoc, etc.,
are efficient fixers of atmospheric nitrogen and are mainly used as inoculants for
cultivation of paddy crops (both in upland and low land conditions) (Priyadarshani
and Biswajit 2012). Jochum et al. 2018 reported that the two strains of N 2 -fixing
cyanobacteria (Anabaena sp. UTEX 2576, Nostoc muscorum UTEX 2209S), and a
polyculture of Chlorella vulgaris (UTEX 2714) and Scenedesmus dimorphus
(UTEX 1237) had improved the efficacy of microalgae based fertilizers in paddy
growth with the help of using vertical semi-closed airlift photo-bioreactor (PBR)
(Jochum et al. 2018). Anabaena in conjugation with the water fern Azolla contributes
nitrogen (approximately 60 kg/ha/season) and also enhances soil quality with
organic substances (Priyadarshani and Biswajit 2012).
7.3
Energy Prospects from Microalgae with Special Reference
to Bioenergy
Speedily dwindling geological reservoirs, swelling energy demands, and increasing
global concerns about the environment have compelled mankind to search for petro
fuel substitutes. In this regard, numerous plant species have been investigated as
potential source of biofuel; however, several lacunas associated with terrestrial
energy crops/oil crops and lignocellulosic biofuel hinder their progression and
popularity. On the global forefront, microalgae have been projected as a prime
bioenergy source with the potential to replace conventional petro fuels (Chisti
2007). As discussed earlier in the introduction section, algae offer several
advantages as compared to oil crops/energy crops and consequently have been
extensively researched as a replacement for the predominant biofuel sources like
sugarcane and corn. Several developed nations, emerging economies, and reputed
companies like ExxonMobil, Sapphire Energy, Algenol, Solazyme, etc., have been
already working towards the concept to commercialization of microalgal biofuel.
7.3.1 Biodiesel from Microalgae
Conventionally biofuel is mostly produced from plant oils such as corn, canola,
soybean, rape seed, palm oil, Jatropha, Pongamia, coconut, ground nut, sunflower,
mustard, etc. But none of these feedstocks can even pragmatically satisfy even a
fraction of the present burgeoning need for energy (liquid biofuel). Furthermore, the
conundrum of the Food Vs Fuel debate has geared up the quest for newer, sustainable, cost efficient, and environmentally benign feedstock for biodiesel (fatty acid
methyl esters) production. A possible exception that may roll up the dice in favor of
sustainability in near future is biodiesel production from microalgae. Over the past
few decades microalgae have been the center of bioenergy research consideration.
Microalgae today lie in the vanguard of bioenergy research as an emerging and
promising feedstock for biodiesel production. Microalgal biodiesel research is now
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M. M. Phukan et al.
(Malik et al. 2001). Cyanobacterial species like Tolypothrix, Anabaena, Nostoc, etc.,
are efficient fixers of atmospheric nitrogen and are mainly used as inoculants for
cultivation of paddy crops (both in upland and low land conditions) (Priyadarshani
and Biswajit 2012). Jochum et al. 2018 reported that the two strains of N 2 -fixing
cyanobacteria (Anabaena sp. UTEX 2576, Nostoc muscorum UTEX 2209S), and a
polyculture of Chlorella vulgaris (UTEX 2714) and Scenedesmus dimorphus
(UTEX 1237) had improved the efficacy of microalgae based fertilizers in paddy
growth with the help of using vertical semi-closed airlift photo-bioreactor (PBR)
(Jochum et al. 2018). Anabaena in conjugation with the water fern Azolla contributes
nitrogen (approximately 60 kg/ha/season) and also enhances soil quality with
organic substances (Priyadarshani and Biswajit 2012).
7.3
Energy Prospects from Microalgae with Special Reference
to Bioenergy
Speedily dwindling geological reservoirs, swelling energy demands, and increasing
global concerns about the environment have compelled mankind to search for petro
fuel substitutes. In this regard, numerous plant species have been investigated as
potential source of biofuel; however, several lacunas associated with terrestrial
energy crops/oil crops and lignocellulosic biofuel hinder their progression and
popularity. On the global forefront, microalgae have been projected as a prime
bioenergy source with the potential to replace conventional petro fuels (Chisti
2007). As discussed earlier in the introduction section, algae offer several
advantages as compared to oil crops/energy crops and consequently have been
extensively researched as a replacement for the predominant biofuel sources like
sugarcane and corn. Several developed nations, emerging economies, and reputed
companies like ExxonMobil, Sapphire Energy, Algenol, Solazyme, etc., have been
already working towards the concept to commercialization of microalgal biofuel.
7.3.1 Biodiesel from Microalgae
Conventionally biofuel is mostly produced from plant oils such as corn, canola,
soybean, rape seed, palm oil, Jatropha, Pongamia, coconut, ground nut, sunflower,
mustard, etc. But none of these feedstocks can even pragmatically satisfy even a
fraction of the present burgeoning need for energy (liquid biofuel). Furthermore, the
conundrum of the Food Vs Fuel debate has geared up the quest for newer, sustainable, cost efficient, and environmentally benign feedstock for biodiesel (fatty acid
methyl esters) production. A possible exception that may roll up the dice in favor of
sustainability in near future is biodiesel production from microalgae. Over the past
few decades microalgae have been the center of bioenergy research consideration.
Microalgae today lie in the vanguard of bioenergy research as an emerging and
promising feedstock for biodiesel production. Microalgal biodiesel research is now
144
M. M. Phukan et al.