252
information on bioprospecting of microalgae under oxidative stress conditions,
mainly for their carotenoid accumulation and biofuel potential. An overview of
omics platform including genomics, transcriptomics, proteomics and metabolomics
is also provided in the context of better understanding the stress response of microalgae at cellular level and using these advanced approaches for the development of
microalgal biofactory.
Keywords Microalgae • Bioprospecting • Oxidative stress • Reactive oxygen species • Biofuel • Carotenoids • Omics
Contents
13.1 Microalgae and an Overview of Microalgal Applications ............................................. 252
13.2 Oxidative Stress and Reactive Oxygen Species ............................................................. 254
13.3 Role of Oxidative Stress in Carotenoid Accumulation in Microalgae ........................... 257
13.4 Link Between Oxidative Stress and Biofuel Potential of Microalgae ........................... 262
13.5 Other Recent Applications of Microalgae Linked with Oxidative Stress ...................... 266
13.6 Systems Biology and Omics Platform for Microalgal Biofactory ................................. 267
13.7 Conclusion and Future Perspectives .............................................................................. 270
References ................................................................................................................................. 271
13.1 Microalgae and an Overview of Microalgal Applications
Microalgae are unicellular, microscopic (2–200 μm), polyphyletic, CO 2 evolving
and sunlight-driven cell factories found in diverse environmental conditions and
habitats such as lacustrine, brackish, freshwater, hyper-saline, wastewater ponds,
dams, rivers, marine and coastal areas. In any habitat, microalgae have been shown
to have successional tendencies due to variable nutrient availability, inclement
weather and seasonal variations (Bernal et al. 2008). They are autotrophic organisms which grow by photosynthesis and are considered as eukaryotes, although the
prokaryotic cyanobacteria are also included in this category (Greenwell et al. 2009).
The enormous biodiversity of microalgae represent almost untapped resource. It has
been estimated that about 20,000–800,000 microalgal species exist, of which only
about 50,000 species are reported (Suganya et al. 2016).
The use of microalgae by humans started when the Chinese used Nostoc and few
other cyanobacteria as a food source around 2000 years ago. After World War II, the
USA, Germany and Japan started mass culture of microalgae to meet the increasing
food demand (Ratha and Prasanna 2012). Since then microalgae have been explored
for the control of water pollution, regeneration of atmosphere in biospheres, mitigation of greenhouse gases, etc. With simple growth requirements (light, CO 2 , N, P
and K), microalgae produce a wide range of potential metabolic products such as
pigments, fatty acids, vitamins, carotenoids, antioxidants, enzymes, toxins, food
supplements, pharmacological substances, polymers, etc. (Pancha et al. 2015a, b;
Araujo et al. 2011). Microalgae are a great source of natural compounds which
K. Chokshi et al.
information on bioprospecting of microalgae under oxidative stress conditions,
mainly for their carotenoid accumulation and biofuel potential. An overview of
omics platform including genomics, transcriptomics, proteomics and metabolomics
is also provided in the context of better understanding the stress response of microalgae at cellular level and using these advanced approaches for the development of
microalgal biofactory.
Keywords Microalgae • Bioprospecting • Oxidative stress • Reactive oxygen species • Biofuel • Carotenoids • Omics
Contents
13.1 Microalgae and an Overview of Microalgal Applications ............................................. 252
13.2 Oxidative Stress and Reactive Oxygen Species ............................................................. 254
13.3 Role of Oxidative Stress in Carotenoid Accumulation in Microalgae ........................... 257
13.4 Link Between Oxidative Stress and Biofuel Potential of Microalgae ........................... 262
13.5 Other Recent Applications of Microalgae Linked with Oxidative Stress ...................... 266
13.6 Systems Biology and Omics Platform for Microalgal Biofactory ................................. 267
13.7 Conclusion and Future Perspectives .............................................................................. 270
References ................................................................................................................................. 271
13.1 Microalgae and an Overview of Microalgal Applications
Microalgae are unicellular, microscopic (2–200 μm), polyphyletic, CO 2 evolving
and sunlight-driven cell factories found in diverse environmental conditions and
habitats such as lacustrine, brackish, freshwater, hyper-saline, wastewater ponds,
dams, rivers, marine and coastal areas. In any habitat, microalgae have been shown
to have successional tendencies due to variable nutrient availability, inclement
weather and seasonal variations (Bernal et al. 2008). They are autotrophic organisms which grow by photosynthesis and are considered as eukaryotes, although the
prokaryotic cyanobacteria are also included in this category (Greenwell et al. 2009).
The enormous biodiversity of microalgae represent almost untapped resource. It has
been estimated that about 20,000–800,000 microalgal species exist, of which only
about 50,000 species are reported (Suganya et al. 2016).
The use of microalgae by humans started when the Chinese used Nostoc and few
other cyanobacteria as a food source around 2000 years ago. After World War II, the
USA, Germany and Japan started mass culture of microalgae to meet the increasing
food demand (Ratha and Prasanna 2012). Since then microalgae have been explored
for the control of water pollution, regeneration of atmosphere in biospheres, mitigation of greenhouse gases, etc. With simple growth requirements (light, CO 2 , N, P
and K), microalgae produce a wide range of potential metabolic products such as
pigments, fatty acids, vitamins, carotenoids, antioxidants, enzymes, toxins, food
supplements, pharmacological substances, polymers, etc. (Pancha et al. 2015a, b;
Araujo et al. 2011). Microalgae are a great source of natural compounds which
K. Chokshi et al.