267
environment through bioadsorption, i.e. adhesion of metals to cellular surfaces, and
bioaccumulation, i.e. intracellular accumulation. Recently, Belghith et al. (2016)
reported metal removal capacity of D. salina under cadmium stress. As the metal
concentration in the medium increased, the total removed cadmium by the cells also
increased. Cadmium removal of 35.85% was observed at 75 mg/L concentration.
Exposure of cadmium reduced the carbohydrate and increased the total metallothionein’s protein content of the cells. The accumulation of carotenoid increased with the
increase in the concentration of cadmium in the medium, while the amounts of polyphenols and flavonoids varied with cadmium concentration.
Rai et al. (2013) observed a concentration-dependent increase in the activity of
SOD, CAT and APX and accumulations of carotenoid and MDA in C. vulgaris
exposed to 0.01–100 μg/ml of chromium. Sabatini et al. (2009) studied oxidative
stress and antioxidant response of Scenedesmus vacuolatus exposed to different
concentrations of copper (6.2, 108, 210 and 414 μM) for 1 week. The increase in the
concentration of copper in culture medium resulted in the significant increase of the
total copper in S. vacuolatus along with their protein and MDA contents. Cells
exhibited a significant increase in the CAT and SOD activity along with higher glutathione content in 414 μM copper.
13.6 Systems Biology and Omics Platform for Microalgal
Biofactory
Systems biology is a comprehensive quantitative analysis of the manner in which all
the components of a biological system interact functionally over time (Aderem
2005). The recent advances in systems biology utilizing the omics—genomics, transcriptomics, proteomics and metabolomics—approaches are now unlocking novel
metabolic capabilities of microalgae and highlight them as a multiuse feedstock
(Guarnieri and Pienkos 2015). A combinatorial approach using multiple omics platforms and the integration of their outcomes is now an effective strategy for clarifying the molecular systems that are integral for microalgal biofactory. Omics data
sets can be used to construct in silico metabolic models of biochemical reaction
networks for the analysis and prediction of cellular behaviour under genetic and
environmental perturbations (Hong and Lee 2015), thus allowing the design of more
efficient microalgae with the enhanced level of targeted products.
Genomics is considered as the generation and analyses of nucleotide sequences
of the genome as well as cDNA collections. From sequences, individual genes
and repeat elements are identified, the organization and arrangement of genes are
analysed and comparisons are made among genomes (Jamers et al. 2009), which
assists in phylogenetic analysis and can lead to the discovery of conserved genes
(Hardison et al. 2003). Genomics plays a significant role in systems biology as
genome annotation provides a framework for metabolic reconstruction. The best
studied algal species is C. reinhardtii whose genome draft sequence was completed
13 Oxidative Stress-Induced Bioprospecting of Microalgae
environment through bioadsorption, i.e. adhesion of metals to cellular surfaces, and
bioaccumulation, i.e. intracellular accumulation. Recently, Belghith et al. (2016)
reported metal removal capacity of D. salina under cadmium stress. As the metal
concentration in the medium increased, the total removed cadmium by the cells also
increased. Cadmium removal of 35.85% was observed at 75 mg/L concentration.
Exposure of cadmium reduced the carbohydrate and increased the total metallothionein’s protein content of the cells. The accumulation of carotenoid increased with the
increase in the concentration of cadmium in the medium, while the amounts of polyphenols and flavonoids varied with cadmium concentration.
Rai et al. (2013) observed a concentration-dependent increase in the activity of
SOD, CAT and APX and accumulations of carotenoid and MDA in C. vulgaris
exposed to 0.01–100 μg/ml of chromium. Sabatini et al. (2009) studied oxidative
stress and antioxidant response of Scenedesmus vacuolatus exposed to different
concentrations of copper (6.2, 108, 210 and 414 μM) for 1 week. The increase in the
concentration of copper in culture medium resulted in the significant increase of the
total copper in S. vacuolatus along with their protein and MDA contents. Cells
exhibited a significant increase in the CAT and SOD activity along with higher glutathione content in 414 μM copper.
13.6 Systems Biology and Omics Platform for Microalgal
Biofactory
Systems biology is a comprehensive quantitative analysis of the manner in which all
the components of a biological system interact functionally over time (Aderem
2005). The recent advances in systems biology utilizing the omics—genomics, transcriptomics, proteomics and metabolomics—approaches are now unlocking novel
metabolic capabilities of microalgae and highlight them as a multiuse feedstock
(Guarnieri and Pienkos 2015). A combinatorial approach using multiple omics platforms and the integration of their outcomes is now an effective strategy for clarifying the molecular systems that are integral for microalgal biofactory. Omics data
sets can be used to construct in silico metabolic models of biochemical reaction
networks for the analysis and prediction of cellular behaviour under genetic and
environmental perturbations (Hong and Lee 2015), thus allowing the design of more
efficient microalgae with the enhanced level of targeted products.
Genomics is considered as the generation and analyses of nucleotide sequences
of the genome as well as cDNA collections. From sequences, individual genes
and repeat elements are identified, the organization and arrangement of genes are
analysed and comparisons are made among genomes (Jamers et al. 2009), which
assists in phylogenetic analysis and can lead to the discovery of conserved genes
(Hardison et al. 2003). Genomics plays a significant role in systems biology as
genome annotation provides a framework for metabolic reconstruction. The best
studied algal species is C. reinhardtii whose genome draft sequence was completed
13 Oxidative Stress-Induced Bioprospecting of Microalgae