Determination of Optimum Iron Requirement for Production of Microalgae Biomass as Biofuel Feedstock

Microalgae biomass is considered as one of the promising alternative feedstock for biofuel production. The biomass productivity of some of the microalgae can exceed an order of magnitude compared to any other terrestrial plant. Apart from nitrogen and phosphorus, iron is one of the major elements that must be provided to microalgae culture for high density biomass production. The amount of iron that is required per cell or per unit of microalgae biomass will vary among microalgae strains. Depending on the concentration of iron in the cultivation media, the microalgae will accumulate different amount of iron and this process may alter the compositions of other major metabolites. In order to be competitive the cost of microalgae biomass production should be lower and the desired metabolites should be present in higher percentages; therefore, the appropriate concentration of iron should be determined. On the contrary, there are very limited study on the microalgal iron requirement. The first objective of this study is to determine the minimum concentration of iron requirement by some of the locally isolated potential microalgae. The second objective of this study is to characterize the lipid accumulation under different iron concentrations. Gillard f/2 and BG-11 are the two common nutrients composition used to culture marine and freshwater microalgae respectively. In these two nutrients media, the concentrations of iron are 0.65 mg/l and 1.24 mg/l for Guillard F/2 and BG-11 media respectively. Due to some limitations, in most of the cases the concentrations of phototrophic microalgae in large scale biomass production doesn't exceed 0.5 g/L. If these two media are to be used in large scale, iron requirement can be calculated as 1.3 kg (6.3 kg as FeCl3.6H2O) and 2.4 kg (12 kg as FeCl3.6H2O) respectively for each ton of biomass production. Therefore, the cost of the iron fertilizer can be significant for low cost feedstock; furthermore, if there is residual iron in the discharge water it will require additional treatment steps. Three local marine microalgae (Nannochloris sp., Tetraselmis sp., Chlorocystis sp.) and three local freshwater microalgae (Scenedesmous sp., Chlorella sp., Neochloris sp.) were selected to study their iron requirement. Apart from iron, all the nutrients were added as per f/2 or BG-11 media concentrations. However, for the marine microalgae, the range of iron concentration was 0 to 1 mg/L while for the freshwater microalgae it was 0 to 3 mg/L. All the experiments were conducted in triplicates. 10 ml of culture was inoculated in 90 ml containing any culture media in a 250 ml flask; the flasks were kept in an orbital shaker which was maintained at 120 rpm speed, 25°C, 12 hours photoperiod. The growth period for any strain was kept fixed at 7 days. It was found that marine Naanochloris sp. didn't require the addition of iron; the available iron in the seawater is sufficient to produce 0.5 g/L biomass density. The other two strains had also smaller iron requirement compared to f/2 media. For the three freshwater microalgae, there was also minor requirement for iron (1 mg/L) which was much lesser than iron concentration in BG-11 media. Iron deficiency, during the cultivation process, resulted in bleaching and changes in metabolites (especially in pigments). Nannochloris sp. and Scenedesmous sp. will be later grown in outdoor small raceway tanks (1000 liter) to verify the indoor small scale results.qscienc

Haematococcus pluvialis Microalgae Extract Inhibits Proliferation, Invasion, and Induces Apoptosis in Breast Cancer Cells

Breast cancer (BC) is the most common malignant cancer in females worldwide. Drug resistance, toxicity, and the failure of current therapies to completely cure BC has challenged conventional medicine. Consequently, complementary alternative medicine has become popular due to its safety and efficacy. Haematococcus pluvialis (H. pulvialis) is a green microalga living in fresh water, and its crude extract is rich of bioactives, including carotenoids, known to inhibit cancer cell growth. In the present study, we investigated the effects of a methanol crude extract called "T1" of H. pulvialis on cell growth and migration/invasion of the BC cell line MDA-MB-231 in comparison to the fibroblast control cells. TI significantly suppressed BC cell growth, inhibited migration and invasion and induced apoptosis. Interestingly, apoptosis was mediated by a significant loss of mutant p53 protein, and increased Bax/Bcl2 ratio. Our findings support our hypothesis that T1 exerts its anti-cancer effects by inhibiting BC invasion and inducing apoptosis mediated, at least, via the p53/Bax/Bcl2 pathway. Ongoing experiments aim to identify the molecular mechanisms underpinning T1-inhibited BC cell invasion using pre-designed metastasis gene-based array method.This research was funded by the Qatar University Internal Grant Nos. QUST-2-CAS-2021-137 and QUST-2-CAS-2021-138.Scopu

Вероятностно-временные характеристики и оптимизация ожидаемых доходов моделей информационных систем и сетей

В работе приведен обзор методов и методик исследования сетей массового обслуживания (МО) некоторых новых типов - различных марковских сетей с доходами (НМ-сетей) с дисциплинами обслуживания заявок FIFO в системах, сетей с ограниченным временем ожидания разнотипных заявок в них, обходами систем обслуживания заявками и сетей с положительными и отрицательными заявками (G-сетей), применяемых при нахождении вероятностно-временных характеристик и доходов в информационных системах и сетях (ИСС) и других объектах в переходном режиме

Effect of ethylene-vinyl acetate copolymer on kinematic viscosity and thermal stability of jojoba, date seed, and waste cooking oils in lubricant applications

Vegetable oils possess excellent lubricant properties, but one reason limiting their application as lubricants is their low kinematic viscosity. This study investigated how the addition of ethylene-vinyl acetate copolymer could affect the kinematic viscosity and thermal stability of jojoba, date seed, and waste cooking oils. The yield of oil from jojoba and date seed was 51.7 +- 0.77% and 8.2 +- 0.5%, respectively. The oleic acid content in jojoba, date seed, and waste cooking oils was 3.09, 49.15, and 72.4%, respectively. Kinematic viscosity of date seed oil with 4% ethylene vinyl acetate was 178 +- 2.8 mm2/s at 40  C, whereas the kinematic viscosities of jojoba and waste cooking oil with 4% ethylene vinyl acetate were 170 +- 2.1 and 165 +- 1.4 mm2/s at 40  C. The addition of 4% ethylene vinyl acetate increased kinematic viscosities of date seed, jojoba, and waste cooking oils by a multiplication factor of 5.5, 6.8, and 4.7, respectively. Thermal stability was evaluated using decomposition temperatures. Onset decomposition temperature for jojoba, date seed, and waste cooking oils with ethylene-vinyl acetate was 344, 267, and 339  C, and offset decomposition temperatures were 479, 474, and 450.6  C, respectively. Offset decomposition temperature for jojoba and date seed oils without ethylene-vinyl acetate was 407 and 445  C, whereas the onset temperature of industrial gear oil was 238  C, and the offset temperature was 363  C. Nevertheless, kinematic viscosity and thermal stability of vegetable oil-ethylene vinyl acetate blends were higher than those of industrial gear oil. Graphical abstract: [Figure not available: see fulltext.] 2021, Iran Polymer and Petrochemical Institute.The authors would like to acknowledge the Qatar National Research Fund (QNRF) support for providing funding (under Grant number NPRP8-646-2-272) for this study.Scopu

Utilization of nitrogen-rich agricultural waste streams by microalgae for the production of protein and value-added compounds

Current food and feed production practices via agricultural processes generate waste streams often rich in nitrogen. Conversion of the nitrogen in agricultural waste into valuable products would prevent environmental pollution and promote a circular economy. Nitrogen in agricultural waste could remain in both water-soluble and solid forms. While microalgae could utilize several forms of water-soluble nitrogen in protein-rich biomass, many agricultural wastes would require pretreatment steps so that nitrogen and other elements could be made available for microalgal consumption. In addition to nitrogen recovery, several microalgae could also produce other high-value metabolites (e.g., pigments, polyunsaturated fatty acids, etc.) using waste sources. This review explored the recent advances in microalgal cultivation using agricultural wastes to produce biomass rich in protein and other value-added metabolites for food and feed applications. Finally, the challenges and prospects of microalgal nitrogen recovery from various agricultural wastes are briefly discussed. 2023 Elsevier B.V.The authors would like to acknowledge the support of Qatar National Research Fund (QNRF, a member of Qatar Foundation) for providing the funding (under grant MME1-0910-190028 ) for this study.Scopu

Efficient extraction of lipids from microalgal biomass for the production of biofuels using low-cost protic ionic solvents

The valorization of lipids available in microalgal biomass supports the indispensable transition from fossil fuels to renewable energy systems such as biofuels. Ionic liquids have been long investigated for the effective extraction of those lipids, however; the complex and expensive synthesis of traditional ionic liquids (i.e., >$50/kg) hindered their employment in commercial applications. Protic ionic liquids are a class of ionic liquids that possess a simple method of preparation and a low cost of around$1-3/kg, rendering them viable for industrial implementation. This study investigates, for the first time, the deployment of protic ionic liquids with methanol co-solvent for the extraction of lipids from Coelastrella sp. and Haematococcus sp. microalgae. The treatment process focused on the use of N,N,N-dimethyl-butylammonium hydrogen sulfate due to its high lipid extraction performance of 323.3 mg lipids/g biomass from Coelastrella sp. (81% of available lipids) compared to other screened ionic liquids. Process parameters such as temperature, time, and ionic liquid to methanol mass ratio exhibited a key impact on the lipid yield. The fatty acid profile of the extracted lipids from Coelastrella sp. demonstrated suitability to produce biofuels. The treatment has also shown selectivity in extracting lipids while leaving behind a protein/carbohydrate rich solid residue. The results obtained suggest that protic ionic liquids are promising candidates for the cost-effective and eco-friendly treatment of microalgal biomass. 2023 Elsevier B.V.The authors gratefully acknowledge the financial support provided by Qatar National Research Fund , research grant ( PDRA6-0602-20007 ). The authors would like to express their appreciation for Dr. Touria Bounnit from the department for sustainable development at Qatar University for doing the GC-FID analysis. The statements made herein are solely the responsibility of the authors.Scopu

Sustainable production of toxin free marine microalgae biomass as fish feed in large scale open system in the Qatari desert

Mass cultivation of microalgae biomass for feed should be cost effective and toxin free. Evaporation loss in Qatar can be as high as 2 cm/d. Hence, production of marine microalgae biomass in Qatar would also require mitigating water loss as there was only very limited groundwater reserve. To address these issues, a combination of four growth conditions were applied to a 25,000 L raceway pond: locally isolated microalgae strain was selected which could grow in elevated salinity; strain that did not require silica and vitamins; volume of the culture would increase over time keeping denser inoculum in the beginning, and evaporation water loss would be balanced by adding seawater only. A local saline tolerant Nannochloropsis sp. was selected which did not require silica and vitamins. When the above conditions were combined in the pond, average areal biomass productivities reached 20.37 g/m2/d, and the culture was not contaminated by any toxic microalgae.Qatar Airways, Qatar Science & Technology Park

Optimization of iron dosage for microalgal biomass production as a feedstock for biofuel

Summary: Biomass and metabolite production of three marine (Tetraselmis sp., Nannochloropsis sp., Chlorocystis sp.) and three freshwater microalgae (Scenedesmus sp., Chlorella sp., Monoraphidium sp.) were studied under different iron concentrations. The biomass concentration in control cultures (i.e., no iron added) was in the range of 291.5 707.5 mg/L, suggesting that these microalgae could use dissolved iron in the source water and also the carried over iron from the inoculum. In terms of biomass production, 0.05 mg/L or less Fe3+ supplementation was optimum for all the marine microalgae, however addition of iron did not have any significant effect on the biomass yield of freshwater microalgae (P < 0.05). Different iron supplementations, however, resulted in mixed trends in metabolites contents among these strains. Nevertheless, iron uptake by these microalgae was low while extra iron could remain in the culture media or precipitate. The biomass concentrations of Nannochloropsis sp. and Scenedesmus sp. cultures, when grown in outdoor 1000 L raceway tanks without iron supplementation, were 721.5 mg/L and 530 mg/L, respectively. From the indoor and outdoor experiments, it can be concluded that some microalgae have a very low iron requirement.Scopu

Aquaculture from inland fish cultivation to wastewater treatment: a review

The aquaculture industry is rapidly developing, generating a high amount of wastewater. Inland aquaculture effluents contain nutrients and other substances that can cause eutrophication and the emergence of resistive organisms if released into the environment. Hence, aquaculture wastewater should be treated appropriately for reuse in different applications or safely released into the environment, promoting a sustainable industry and a circular economy. The current review provides insight into aquaculture wastewater generation, constituents, and treatment through various technologies. This study’s treatment technologies could be classified as physical, chemical, and biological. SWOT analysis was conducted on each technology to provide an in-depth understanding of the advantages and drawbacks. Suggestions were also stated to shed light on the importance of a sustainable aquaculture industry and the means to transition toward a circular economy. Graphical abstract: [Figure not available: see fulltext.].This work was funded by Qatar National Research Fund (QNRF) - grant no. (GSRA8-L-2-0509-21037)

Biocrude oil production from a self-settling marine cyanobacterium, Chroococcidiopsis sp., using a biorefinery approach

Although the whole microalgal biomass is typically used as a feedstock for hydrothermal liquefaction (HTL), the conversion of a primary metabolite (i.e., carbohydrate) to biocrude is very low. In this study, a self-settling cyanobacterium (i.e., Chroococcidiopsis sp.) was used to understand the effect of carbohydrate removal, as a pretreatment, on the net energy recovery from the residual biomass. The optimum biocrude yields from pretreated and control biomass were 50.2% (350 °C) and 41.3% (300 °C), respectively. For the temperature range studied, the biocrude yield from the pretreated biomass was higher compared to that obtained from the control feedstock. Further, maximum alkane formation of 42.7 and 23.3% occurred for pretreated and control biomass, respectively, at 325 °C. Total organic carbon and total nitrogen values in the aqueous phase liquid obtained from pretreated biomass were at least 1.31 and 1.23 times lower when compared to the corresponding values obtained from control biomass. When APL was recycled as a source of nutrients, it reduced the biomass yield (24.1%) and pigment content (68.4%) in Chroococcidiopsis sp. Further, a model was developed to understand how the cellular carbohydrate content would affect the net energy recovery for the proposed biorefinery route.The authors would like to acknowledge the support of the Qatar National Research Fund (QNRF, a member of Qatar Foundation) for providing the funding (under grant NPRP8-646-2-272 ) for this study.Scopu