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Economic viability of biodiesel production relies mainly on the productivity of biomass and microalgal lipids. In addition, production of omega fatty acids is favorable for human nutrition. Thus, enhancement of lipid accumulation with high proportion of omega fatty acids could help the dual use of microalgal lipids in human nutrition and biodiesel production through biorefinery. In that context, phytohormones have been identified as a promising factor to increase biomass and lipids production. However, nitrogen limitation has been discussed as a potential tool for lipid accumulation in microalgae, which results in simultaneous growth retardation. The present study aims to investigate the combined effect of N-depletion and 3-Indoleacetic acid (IAA) supplementation on lipid accumulation of the marine eustigmatophyte Nannochloropsis oceanica as one of the promising microalgae for omega fatty acids production. The study confirmed that N-starvation stimulates the lipid content of N. oceanica. IAA enhanced both growth and lipid accumulation due to enhancement of pigments biosynthesis. Therefore, combination effect of IAA and nitrogen depletion showed gradual increase in the dry weight compared to the control. Lipid analysis showed lower quantity of saturated fatty acids (SFA, 26.25%) than the sum of monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Under N-depletion, SFA decreased by 12.98% compared to the control, which recorded much reduction by increasing of IAA concentration. Reduction of SFA was in favor of PUFA, mainly omega-6 and omega-3 fatty acids which increased significantly due to IAA combined with N-depletion. Thus, the present study suggests a biorefinery approach for lipids extracted from N. oceanica for dual application in nutrition followed by biodiesel production.
Hussein Touliabah; Adel Almutairi. Effect of Phytohormones Supplementation under Nitrogen Depletion on Biomass and Lipid Production of Nannochloropsis oceanica for Integrated Application in Nutrition and Biodiesel. Sustainability 2021, 13, 592 .
AMA StyleHussein Touliabah, Adel Almutairi. Effect of Phytohormones Supplementation under Nitrogen Depletion on Biomass and Lipid Production of Nannochloropsis oceanica for Integrated Application in Nutrition and Biodiesel. Sustainability. 2021; 13 (2):592.
Chicago/Turabian StyleHussein Touliabah; Adel Almutairi. 2021. "Effect of Phytohormones Supplementation under Nitrogen Depletion on Biomass and Lipid Production of Nannochloropsis oceanica for Integrated Application in Nutrition and Biodiesel." Sustainability 13, no. 2: 592.
Effects of 12 heavy metals on growth of free and alginate-immobilized cells of the alga Pseudokirchneriella subcapitata were investigated. The tested metals ions include Al, As, Cd, Co, Cr, Cu, Hg, Se, Ni, Pb, Sr, and Zn. Toxicity values (EC50) were calculated by graphical interpolation from dose-response curves. The highest to the lowest toxic metals are in the order Cd > Co > Hg > Cu > Ni > Zn > Cr > Al > Se > As > Pb > Sr. The lowest metal concentration (mg L−1) inhibiting 50% (EC50) of algal growth of free and immobilized (values in parentheses) algal cells were, 0.018 (0.09) for Cd, 0.03 (0.06) for Co, 0.039 (0.06) for Hg, 0.048 (0.050) for Cu, 0.055 (0.3) for Ni, 0.08 (0.1) for Zn, 0.2 (0.3) for Cr, 0.75 (1.8) for Al, 1.2 (1.4) for Se, 3.0 (4.0) for As, 3.3 (5.0) for Pb, and 160 (180) for Sr. Free and immobilized cultures showed similar responses to Cu and Se. The free cells were more sensitive than the immobilized ones. Accordingly, the toxicity (EC50) of heavy metals derived only form immobilized algal cells might by questionable. The study suggests that batteries of alginate-immobilized algae can efficiently replace free algae for the bio-removal of heavy metals.
Zaki M. Al-Hasawi; Mohammad I. Abdel-Hamid; Adel W. Almutairi; Hussein E. Touliabah. Response of Pseudokirchneriella subcapitata in Free and Alginate Immobilized Cells to Heavy Metals Toxicity. Molecules 2020, 25, 2847 .
AMA StyleZaki M. Al-Hasawi, Mohammad I. Abdel-Hamid, Adel W. Almutairi, Hussein E. Touliabah. Response of Pseudokirchneriella subcapitata in Free and Alginate Immobilized Cells to Heavy Metals Toxicity. Molecules. 2020; 25 (12):2847.
Chicago/Turabian StyleZaki M. Al-Hasawi; Mohammad I. Abdel-Hamid; Adel W. Almutairi; Hussein E. Touliabah. 2020. "Response of Pseudokirchneriella subcapitata in Free and Alginate Immobilized Cells to Heavy Metals Toxicity." Molecules 25, no. 12: 2847.
Pennate diatom Nitzschia palea can be cultured in outdoor vertical-bed photobioreactors to produce biodiesel. To assess the production of biomass and lipids, non-axenic cultures of Nitzschia palea were grown outdoors, and the growth of these cultures was measured biweekly. During the annual cycle of algal culture, the culture temperature ranged from 17.3 °C to 33.5 °C, the dry weight biomass ranged from 0.11 g l−1 to 0.25 g l−1, light energy] ranged from 1.94 Wm−2 to 3.9 Wm−2 and intracellular lipid content ranged from 7.1% to 11.4% of biomass weight after drying at 60 °C. Gas chromatography/mass spectroscopy (GC/MS) analysis of n-hexane extracts showed that the intracellular lipids were primarily C14:0 myristic acid (9.01%), C15:0 pentadecyclic acid (8.26%) and two types of C16:0, palmitic acid (41.13%) and palmitoleic acid (29.25%). Gel permeation analysis showed that carboxylic acids comprised 28.9% of lipids, 16.3% of monoglycerides, 27.3% of diglycerides and 24.3% of triglycerides. Alcoholysis of lipids resulted in the conversion of about 93.9% of fatty acids to equivalent fatty acid methyl esters (FAME) or biodiesel, which, on basis of wt%, consisted primarily of C15:0 methyl myristate (8.3%), C16:0 methyl pentadecanoate] (7.2%), C17:1methyl palmitoleate (28.7%) and methyl palimtate](39.8%).
Hussein E. Touliabah; M.I. Abdel-Hamid; Adel Almutairi. Long-term monitoring of the biomass and production of lipids by Nitzschia palea for biodiesel production. Saudi Journal of Biological Sciences 2020, 27, 2038 -2046.
AMA StyleHussein E. Touliabah, M.I. Abdel-Hamid, Adel Almutairi. Long-term monitoring of the biomass and production of lipids by Nitzschia palea for biodiesel production. Saudi Journal of Biological Sciences. 2020; 27 (8):2038-2046.
Chicago/Turabian StyleHussein E. Touliabah; M.I. Abdel-Hamid; Adel Almutairi. 2020. "Long-term monitoring of the biomass and production of lipids by Nitzschia palea for biodiesel production." Saudi Journal of Biological Sciences 27, no. 8: 2038-2046.
Plasmid pBI221aadAGUS which carried both of GUS (β-glucuronidase) and aadA (aminoglyoside transferase) genes besides of the 35S cauliflower mosaic virus promoter was constructed and used for stable nuclear transformation of Chlamydomonas reinhardtii. The vector was transformed into the alga by particle gun bombardment and two positive colonies were selected on spectinomycin–containing medium. The restriction analysis of the DNA of the positive colonies showed that aadA was inserted in two orientations. The presence of introduced genes in the transformed colonies was confirmed by (PCR) using primers specific to GUS and aadA genes. The expression of aadA and GUS genes was revealed in all colonies that were grown on spectinomycin in liquid culture for 3–4 generations. The usefulness of this vector, differing in the orientation of the aadA cassette, was manisfested by transforming C. reinhardtii to spectinomycin resistance in the stable expression. This constructed plasmid-based expression vector system would help to unravel the functions of various genes in the green alga.
Mostafa M. El-Sheekh; Adel W. Almutairi; Hussein E. Touliabah. Construction of a novel vector for the nuclear transformation of the unicellular green alga Chlamydomonas reinhardtii and its stable expression. Journal of Taibah University for Science 2019, 13, 529 -535.
AMA StyleMostafa M. El-Sheekh, Adel W. Almutairi, Hussein E. Touliabah. Construction of a novel vector for the nuclear transformation of the unicellular green alga Chlamydomonas reinhardtii and its stable expression. Journal of Taibah University for Science. 2019; 13 (1):529-535.
Chicago/Turabian StyleMostafa M. El-Sheekh; Adel W. Almutairi; Hussein E. Touliabah. 2019. "Construction of a novel vector for the nuclear transformation of the unicellular green alga Chlamydomonas reinhardtii and its stable expression." Journal of Taibah University for Science 13, no. 1: 529-535.