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

Abstract

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.

Physiological and Biochemical Responses of Bicarbonate Supplementation on Biomass and Lipid Content of Green Algae Scenedesmus sp. BHU1 Isolated From Wastewater for Renewable Biofuel Feedstock

“…Two lipophylic dyes BODIPY 505/515 and Nile Red (NR-47353) powder (0.250 μg) were dissolved in 1 ml of acetone, which was used as the stock solution to detect the presence of neutral lipid in microalgal cells ( Singh et al, 2019 ). Stationary phase microalgal cells (2 ml) were collected by centrifugation and washed three times with 1x Phosphate Buffer Saline (PBS).…”

Elevated inorganic carbon and salinity enhances photosynthesis and ATP synthesis in picoalga Picocystis salinarum as revealed by label free quantitative proteomics

“…), bacteriocins, bioactive and antimicrobial compounds (Upasani and Desai, 1990;Sahay et al, 2012;Kajale et al, 2020). Among microalgae, cyanobacteria Arthrospira and green algae Dunaliella have received enormous scientific attention and have been widely characterized for various biotechnological applications (Phadwal and Singh, 2003;Kulshreshtha and Singh, 2013;Singh and Singhm, 2014;Singh et al, 2018;Vidyalaxmi et al, 2019;Ma et al, 2019;da Silva et al, 2021;Gonzalez and Laroche, 2021). Recent culture independent multi-omics study shed light on the microbiome evolution of lake Sambhar in comparison to other saline ecosystems, reported relative abundance of members of Archaea, Bacteria and Eukaryota domain, with Dunaliella well recognized under Chlorophyceae (Mehta et al, 2021), however, P. salinarum remains unreported.…”

Two splice variants of the DsMEK1 mitogen-activated protein kinase kinase (MAPKK) are involved in salt stress regulation in Dunaliella salina in different ways

“…Intracellular glycerol content of D. salina subjected to 3.5 M salinity concentrations was measured using the method of Prabhakar et al [52] with slight modifications. All samples (5 mL) were centrifuged (6000 g, 5 min at RT), and the pellets were washed with fresh culture medium.…”