Gamal S. El-Baroty

Enhancement of lipid accumulation in Scenedesmus obliquus by Optimizing CO2 and Fe3+ levels for biodiesel production

The effects of cultivation of Scenedesmus obliquus in nutrient medium supplemented with 0.03%, 3, 9% and 12% CO(2) or 2.5-20 mg L(-1) of Fe(3+) on dry weight of biomass (DW), total lipid accumulation (TL contents) and total lipid productivity (TLP) were evaluated under indoor conditions. The accumulation of TL and TLP showed an increasing trend with increasing of CO(2) or Fe(3+) levels. In cultures with 12% CO(2) or 20mg/L Fe(3+), maximum TL contents of 33.14% and 28.12%, respectively were obtained. These lipids displayed a fatty acid profile which is suitable for biodiesel production as the most abundant compounds were oleic (32.19-34.44%), palmitic (29.54-25.12%) and stearic (12.26-16.58% of total FAMEs) acids. The properties of biodiesel obtained from S. obliquus, were the same with those specification for biodiesel standards including ASTM D 6751 (American Society for Testing Material) and the European Standard En 14214. Thus, S. obliquus biomass could be used as suitable feedstock for biodiesel production.

Fungicidal Activity of Artemisia herba alba Asso (Asteraceae)

The antifungal activity of Artemisia herba alba was found to be associated with two major volatile compounds isolated from the fresh leaves of the plant. Carvone and piperitone were isolated and identified by GC/MS, GC/IR, and NMR spectroscopy. Antifungal activity was measured against Penicillium citrinum (ATCC 10499) and Mucora rouxii (ATCC 24905). The antifungal activity (IC50) of the purified compounds was estimated to be 5 μ g/ml, 2 μ g/ml against Penicillium citrinum and 7 μ g/ml, 1.5 μ g/ml against Mucora rouxii carvone and piperitone, respectively.

Characterization and bioactivity of phycocyanin isolated from Spirulina maxima grown under salt stress

In this study, Spirulina maxima (SM) has been selected following preliminary investigations, for cultivation in either normal (0.02 M) or stress (0.1 M) NaCl medium (Zarrouk) under room conditions to evaluate the possibility of increasing the total phycobiliprotein content (TPC) and their chemical constituents: C-phycocyanin (C-PC), allophycocyanin (APC) and phycoerthrin (PE). TPC material was separated, purified and characterized by various spectroscopic techniques (UV-Vis and IR spectra). The antioxidant activity against free radicals of DPPH, ABTS, superoxide (˙(-)O(2)), hydroxy (˙OH) and reducing power potential were determined. Results indicated a highly significant correlation between increased TPC content in SM cells and the increasing concentration of NaCl in medium, and its chemical constituents were significantly different (P > 0.05). TPC of SM (grown in stress NaCl) containing high amounts of C-PC groups, showed strong antioxidant activity compared with ascorbic acid (standard antioxidant). Although, it activity against different free radicals were found to be variable and dose-dependent. Moreover, the TPC showed lower antimicrobial activity (MIC values in the range of 250-300 μg mL(-1)) than that of chloramphinicol (30 μg mL(-1), reference antimicrobial). Therefore, Spirulina maxima could be cultivated in a salinated open pond, and considered as highly healthy foods and source of natural pigments.

Lipid induction in Dunaliella salina culture aerated with various levels CO2 and its biodiesel production.

In this work, the effect of various levels of CO2 (0.01, 0.03, 3.0, 9.0 and 12.0%) aeration on the biomass production, lipid accumulation and its fatty acid profile as well as biodiesel properties of marine microalgae Dunaliella salina were investigated. The results show that the maximal biomass and lipid productivity (in parenthesis) in cultures aerated with different levels of 0.01, 0.03, 3.0, 9.0 and 12.0% CO2 were 255 (5.36), 412 (15.10), 781 (25.32), 1451 (41.96) and 951 mg/L (59.23 mg L-1d-1), respectively. Whereas, the lipid contents in cells were 2.33, 5.62, 10.28, 28.36 and 40.65%, respectively. Moreover, the levels of CO2 in culture medium had significant effect on fatty acid composition of D. salina. Linolenic and palmitic acids were identified as the major fatty acids in D. salina cells grown at different levels of CO2. The quality of biodiesel produced from algal lipid by a transesterification reaction was located between the limit imposed by the European Standards (EU 14214) and ASTM (US D6751). Based on the results obtained, D. salina could be used for mass-cultured in outdoor ponds, as a promising alternative to current CO2 mitigation strategy and as a suitable feedstock for biodiesel production.

The Potential Use of Microalgal Carotenoids as Dietary Supplements and Natural Preservative Ingredients

Dunaliella salina has been selected as the most valuable microalgae for production of carotenoids as a source of natural pigment when grown under defined conditions. Compared with optimal conditions, D. salina contained higher amounts of total carotenoids (TCAR, 12.6%, dw)—including β-carotene (60.4%, of total carotenoids), astaxanthin (17.7%), zeaxanthin (13.4%), lutein (4.6%), and cryptoxanthin (3.9%)—when grown under stress conditions. These TCAR showed greater in vitro antioxidant potential by inhibition of lipid peroxidation of rat liver microsomes induced by Fe++/ascorbate and Fe++/H2O2 model systems than butylated hydroxytoluene (BHT). The toxicological evaluation of D. salina functional ingredients as an antioxidant and natural food colorant was conducted, in which male albino rats were fed ad libitum for 6 weeks with one of the following diets: standard diet (S), S diets containing 0.5 g trans β-carotene/kg diets (S + 0.5 β C), S + 0.5 g D. salina carotenoids/kg diets (S + 0.5 DC), and S + 1.0 g D. salina carotenoids/kg diets (S + 1.0 DC). Generally, no mortality or treatment-related toxicological signs were observed in any of the rats during the 6 weeks of the experiment. The concentrations of glucose and glycogen in liver and glucose, total proteins, bilirubin, and creatinine as well as enzymes activities of aspartate (AST) and alanine aminotransferases (ALT), and alkaline phosphatase (ALP) in plasma were not significantly different from each other in all four diets. In contrast, the levels of total lipids and lipids components showed significant differences in all groups. Groups S + 0.5 βC, S + 0.5 DC, and S + 1.0 DC showed a significant decrease in concentrations of total lipids, triglycerides, total cholesterol, and phospholipids in either plasma or hepatic tissues compared with S group. The results showed that D. salina carotenoids could be potentially rich sources of natural antioxidants and food colorants and have hypolipidemic and hypocholesterolemic properties.