Bioenergy application of Dunaliella salina SA 134 grown at various salinity levels for lipid production

Khadim

et al. 2018

Journal of Phycology

The objective of the present study was to characterize intrinsic physiological and biochemical properties of the wall-less unicellular cholorophyte Dunaliella salina isolated from a hypersaline Sambhar Lake. The strain grew optimally at 0.5 M NaCl and 16:8 h L:D photoperiod along with maintaining low level of intracellular Na even at higher salinity, emphasizing special features of its cell membranes. It was observed that the cells experienced stress beyond 2 M NaCl as evidenced by increased intracellular reactive oxygen species and antioxidative enzymes, nevertheless proline and malondialdehyde content declined sharply accompanied by higher neutral lipid accumulation. Salinity exceeding 2 M resulted decrease in photosynthetic quantum yield (Fv/Fm) and enhanced glycerol synthesis accompanied by leakage. Super oxide dismutase seemed to play a pivotal role in antioxidative defense as eight isoforms were expressed differentially while catalase and glutathione peroxidase showing no significant change in their expression at higher salinity. The ability of D. salina to grow in range of salinities by sustaining healthy photosynthetic apparatus along with accumulation of valuable products made this alga an ideal organism that can be exploited as resource for biofuel and commercial products.

Section: Discussionsupporting

confidence: 93%

“…, Ahmed et al. ). Production of neutral lipids in Chlamydomonas was correlated with the larger cell size at higher NaCl concentrations (Yao et al.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Biochemical and physiological characterization of a halotolerant Dunaliella salina isolated from hypersaline Sambhar Lake, India

Khadim

et al. 2018

Journal of Phycology

“…Recently, new strains with different ability to accumulate carotenoids and different capacity of photoprotection against high light stress have been isolated; the most promising strain was characterized by a β-carotene productivity of 3.5 g l −1 day −1 at 1500 µmol m −2 s −1 [ 36 ]. Currently, various strains of D. salina growing at different salinity conditions are available [ 37 ].…”

Section: Main Textmentioning

confidence: 99%

Biomass from microalgae: the potential of domestication towards sustainable biofactories

et al. 2018

Interest in bulk biomass from microalgae, for the extraction of high-value nutraceuticals, bio-products, animal feed and as a source of renewable fuels, is high. Advantages of microalgal vs. plant biomass production include higher yield, use of non-arable land, recovery of nutrients from wastewater, efficient carbon capture and faster development of new domesticated strains. Moreover, adaptation to a wide range of environmental conditions evolved a great genetic diversity within this polyphyletic group, making microalgae a rich source of interesting and useful metabolites. Microalgae have the potential to satisfy many global demands; however, realization of this potential requires a decrease of the current production costs. Average productivity of the most common industrial strains is far lower than maximal theoretical estimations, suggesting that identification of factors limiting biomass yield and removing bottlenecks are pivotal in domestication strategies aimed to make algal-derived bio-products profitable on the industrial scale. In particular, the light-to-biomass conversion efficiency represents a major constraint to finally fill the gap between theoretical and industrial productivity. In this respect, recent results suggest that significant yield enhancement is feasible. Full realization of this potential requires further advances in cultivation techniques, together with genetic manipulation of both algal physiology and metabolic networks, to maximize the efficiency with which solar energy is converted into biomass and bio-products. In this review, we draft the molecular events of photosynthesis which regulate the conversion of light into biomass, and discuss how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. We outline major successes reached, and promising strategies to achieving significant contributions to future microalgae-based biotechnology.

“…Moreover, domestication strategies have been developed in C. sorokiniana to generate mutant strains with enhanced biomass productivity [12]. In other Chlorophyta, limitations related to the lack of optimized genetic tools still exist, and particularly concern strains relevant for industrial applications: Dunaliella salina, extensively cultured in open ponds and photobioreactor for β-carotene [13] and lipids production [14] and Haematococcus pluvialis, an industrial source of astaxanthin [15]. Members of the Nannochloropsis genus, and the diatom Phaeodactylum tricornutum, all belonging to Heterokonta, are obligate photoautotrophs that have been intensively characterized, and are also well-developed models for studying microalgal molecular physiology and genetic engineering.…”

mentioning

confidence: 99%

Potential and Challenges of Improving Photosynthesis in Algae

Vecchi

Barera

Bassi

et al. 2020

Plants

108

Sunlight energy largely exceeds the energy required by anthropic activities, and therefore its exploitation represents a major target in the field of renewable energies. The interest in the mass cultivation of green microalgae has grown in the last decades, as algal biomass could be employed to cover a significant portion of global energy demand. Advantages of microalgal vs. plant biomass production include higher light-use efficiency, efficient carbon capture and the valorization of marginal lands and wastewaters. Realization of this potential requires a decrease of the current production costs, which can be obtained by increasing the productivity of the most common industrial strains, by the identification of factors limiting biomass yield, and by removing bottlenecks, namely through domestication strategies aimed to fill the gap between the theoretical and real productivity of algal cultures. In particular, the light-to-biomass conversion efficiency represents one of the major constraints for achieving a significant improvement of algal cell lines. This review outlines the molecular events of photosynthesis, which regulate the conversion of light into biomass, and discusses how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. This review highlights the most recent results in the manipulation of the fundamental mechanisms of algal photosynthesis, which revealed that a significant yield enhancement is feasible. Moreover, metabolic engineering of microalgae, focused upon the development of renewable fuel biorefineries, has also drawn attention and resulted in efforts for enhancing productivity of oil or isoprenoids.