Dry Algae Research Articles

Removal of Pb(II) pollution by algae-Fe-Ni magnetic nanocomposite

A magnetic nanocomposite material was synthesized by combining Chaetomorpha Algae with a Fe–Ni alloy. The dry algae, Fe, and Ni were mechanically alloyed using a ball milling technique in an argon atmosphere. The resulting Algae-Fe-Ni Magnetic Nanocomposite (AFNMN) was characterized using various analytical techniques, including particle size distribution (PSD) analysis, Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), vibrating sample magnetometry (VSM), atomic absorption spectroscopy (AAS), and Fourier transform infrared (FTIR) spectroscopy. Multiple isotherm models were employed to study the adsorption of Pb(II) ions onto the AFNMN material. Density functional theory (DFT) was applied to predict the most stable amino acids for the removal of Pb(II) pollutants from a set of 14 amino acids. To optimize the Pb(II) uptake performance, three key experimental parameters were fine-tuned: pH, temperature, and reactor vessel geometry. Four different optimization methods were utilized, including response surface methodology (RSM), fuzzy logic, adaptive network-based fuzzy inference system (ANFIS), and artificial neural network genetic algorithms (ANN-GA). Additionally, a heat transfer simulation was conducted to determine the optimal vessel positions for achieving the desired temperature variations within the reactor during the adsorption process.

The Bioremoval of Toxic Dyes Using Chlorella Algae in Airlift Bioreactor

<p style="text-align:justify; margin-bottom:11px"><span style="font-size:11pt"><span style="line-height:107%"><span style="font-family:Calibri,sans-serif"><span style="font-size:14.0pt"><span style="line-height:107%"><span style="font-family:"Times New Roman",serif">Malachite green (MG) and Crystal Violet (CV) are used mainly as dyestuff and antimicrobials in aquaculture. They have a severe toxic effect on the environment. Several techniques were used to remove impurities from an aqueous solution: chemical, physical, and electrical. Among all these techniques, using dry algae is a more economical and helpful process. This study aims to investigate using an airlift reactor in the removal of MG and CV by chlorella algae as a biosorbent under different variables. The experiments were carried out in an airlift bioreactor. The experiments were carried out under the effect different operating conditions of initial dye concentration (5-40 ppm), alga dosage (0.3-1.8 gm/l), pH (3–10), air flow rate (0-40 ml/min), temperature (298-318 K) and contact time (5-60 min).  The results show that the introduce of air bubbles significantly enhances the removal efficiency of the dye. The best removal effectiveness was 95.2% for MG dye and 96.1% for CV dye.  The thermodynamics results reveal that the processes are exothermic for both dyes. Kinetic and adsorption isotherms results show the best fit is pseudo-second order and Langmuir model. The mass model result shows that the liquid film diffusion model was the best-fitted for both dyes.</span></span></span></span></span></span></p>

Nitrogen Mineralization of Selected Organic Materials and Their Combined Effects with Nitrogen Fertilizer on Spinach Yield.

A 2-month incubation study was carried out using two soil types to determine the nitrogen mineralization of different inorganic-organic amendments. The following seven treatments (Ts) were established: T1 = control (no amendment), T2 = 5 g of dry algae per kg of soil (100%DA), T3 = 136 g of agri-mat per kg of soil (100%GAM), T4 = 61 g of ground grass per kg of soil (100%GG), T5 = 0.6 g of N using lime-ammonium nitrate (LAN) + 2.5 g of dry algae (50%DA50NF), T6 = 50%GAM50NF, and T7 = 50%GG50NF. Three samples per treatment were obtained at 0, 3, 7, 15, 30, 45, and 60 days for N mineral determination. A 2-month glasshouse experiment was established afterward with the following five treatments: T1 = control, T2 = 50%DA, T3 = 50%GAM, T4 = 50%GG, and T5 = 100 NF. The results indicate that nitrogen mineralization was significantly higher in organic-inorganic amendments compared with singular organic amendments. The percentage differences ranged from 157% to 195%. The 50%DA treatment increased the spinach yield by 20.6% in sandy loam and 36.5% in loam soil. It is difficult to fully recommend the 50%DA treatment without field-scale evaluation, but it is a promising option to be considered.

Optimal growth conditions to enhance Chlorella vulgaris biomass production in indoor phyto tank and quality assessment of feed and culture stock

Commercial microalgae cultivation is a dynamic field with ongoing efforts to improve efficiency, reduce costs, and explore new applications. We conducted a study to examine how different light exposure periods affect Chlorella vulgaris's growth. We employed a Phyto tank batch system of approximately 3.5 L with LED light control, controlled airflow, and sterilized bags, maintained at 22.0 ± 2.0 °C indoors. Various methods, including spectrophotometry, and cell counter were employed to monitor Chlorella vulgaris growth under different light exposure cycles. Additionally, quality analysis as feed source was employed by proximate, amino acid, beta-glucan, and microbial content analysis. The results revealed significant variations in C. vulgaris biomass production based on light exposure duration. Notably, the 16:8-h light-dark photoperiod exhibited the highest biomass concentration, reaching 6.48 × 107 ± 0.50 cells/mL with an optical density (OD) of 1.165 absorbance at 682 nm. The 12:12-h light-dark photoperiod produced the second-highest biomass concentration, with 2.305 × 106 ± 0.60 cells/mL at an OD of 0.489. Proximate analysis of dry algae powder revealed low lipid content (0.48 %), high protein content (37.61 %), variable ash concentration (average 10.75 %), and a significant carbohydrate fraction (51.16 %) during extended daylight and shorter dark periods. Amino acid analysis identified nine essential amino acids, with glutamic acid being the most abundant (17.7 %) and methionine the least (0.4 %). Furthermore, quality analysis and microbiological assays demonstrated that the C. vulgaris biomass is well-suited for fish and livestock use as a feed source and possibility as human nutraceuticals. These findings can be considered more environmentally friendly and ethically sound due to the absence of genetic modification.

Green building future: algal application technology

In the context of rising global energy demands driven by population growth and urbanization, the construction industry significantly contributes to greenhouse gas emissions during the construction phase and subsequent energy consumption. Fossil fuel dependency for heating and energy needs exacerbates climate change, necessitating urgent solutions. Algal technology emerges as a promising strategy for green building practices, addressing energy efficiency and emissions reduction. Algae's unique ability to absorb carbon dioxide (CO2) through photosynthesis is harnessed by deploying photobioreactors on building exteriors. Studies indicate that each kilogram of dry algae consumes 1.83 kg of CO2 while offering applications as organic fertilizer, oil, and protein sources. This technology not only diminishes CO2 emissions but also transforms wastewater and generates bioenergy, catering to building energy requirements. Algal technology's economic and environmental significance becomes evident through carbon capture, energy generation, and circular waste management, aligning with sustainability principles. This study highlights the potential of algal technology to shape the future of eco-friendly conscious construction practices, providing avenues for reduced emissions, efficient energy utilization, and sustainable development.

Red Algae Palmaria Palmata: Biological and Chemical-Technological Characteristics, Recommendations for Its Use as a Source of Nutrients in Human Nutrition

One of the ways to develop micronutrient balanced products may be to include P. palmata red algae in its formulation. The aim is to study the biochemical parameters of P. palmata growing in the White Sea, and to assess the prospects of its use in human nutrition. The thesis presents the biological and chemical-technological characteristics, as well as the results of the drying process of P. palmata growing in the coastal zone of the White Sea, Solovetsky Islands. Analysis of the chemical composition of P. palmata showed that the main components were carbohydrates (45.6–75%) including fiber – 3.6–7.7%, proteins – 7.04–22.62%, ash –18.03–31.74%. The research presents the macro- and microelement composition of P. palmata collected in 2022 in the White Sea. 1 gram of dry algae for iodine, chromium by 12–16% corresponds to the norms of physiological need. The amino acid score value for all essential amino acids is less than 100%, while the limiting amino acids are lysine and threonine. The difference coefficient of amino acid score is 7.6%, the biological value of P. palmata protein is 92%. The dried P. palmata yield from raw algae is 18–20%. Under favorable weather conditions, Palmaria layers are dried to 10–15% water content within 23–26 hours. Based on the results of studies on the safety indicators and chemical composition of P. palmata, the authors demonstrated its applicability in food formulations development as a source of biologically active substances, such as amino acids. Alcohol extracts obtained from P. palmata have antimicrobial activity against Proteus vulgaris and Pseudomonas aeruginosa. In this regard, alcohol extracts from P. palmata can probably be used as an antimicrobial agent in the process of food production.

Porous cellulose microspheres loaded with dry Nile water algae for removal of MB dye and copper ions from aqueous media

AbstractLow‐cost‐effective applied technologies for water and wastewater treatment, such as microalgae, have growing attention due to their mutual benefit in wastewater treatment and for valuable algae biomass production. A newly constructed Nile water algae cross‐linked cellulose microsphere (NACS) was applied by functionalization of cross‐linked cellulose acetate with dry Nile water algae forming an efficient adsorptive microsphere. The adsorption capacity of microspheres was evaluated for the removal of basic dye (Methylene blue: MB) and heavy metal copper ions (Cu+2). The molecular structure revealed that the prepared microspheres have several functional groups and elements that have a high affinity for heavy metals and dye removal; furthermore, the morphological structure emphasizes this removal affinity by the presence of micropores at the surface of the microsphere. The results of maximum biosorption conditions showed both MB and Cu through the microsphere were 20 mg/L MB and (10 and 20) mg/L Cu concentrations, 2 g/L of adsorbent dose, pH (MB = 6 and Cu = 5.5), and contact time of 60 min. The maximum adsorption capacities (qmax) were significantly enhanced at 200 and 153.2 mg/g for MB and Cu (II), respectively. The possibility of removal, recovery, and reuse of MB by prepared microsphere was efficiently achieved.

Determination of kelp (Laminaria digitata) technological characteristics depending on the drying method

The paper considers four methods of drying kelp (Laminaria digitata): convective dehydration at an air temperature of minus 5 oС, relative air humidity of 55 and 90 %; vacuum drying at a metal carrier temperature of 20°C and a vacuum depth of 250 Pa; convective dehydration at an air temperature of 20°C and a relative air humidity of 35 %. In dried algae, the final moisture content, water activity, and strength characteristics were evaluated. To determine the swelling coefficient, dry algae were pre-crushed. It was established that at a temperature of minus 5°C and a relative air humidity of 90 %, dehydration had an unsatisfactory result in terms of the final moisture content of the finished product 27.4 %. This type of drying at a relative air humidity of 55 % provides a final moisture content of the product (12.3 ± 0.48) % and a relatively high swelling coefficient of 6.9. Algae, dehydrated at minus 5°C, had elastic properties, in contrast to other considered methods. Vacuum drying made it possible to obtain the minimum final moisture content of dry algae and the highest swelling coefficient of 7.7. However, drying to constant weight lasted 25.5 hours. Of the considered drying options, the convective method (t = 20°C) showed the highest rate. The duration of drying to constant weight was 8 hours. The final moisture content of the product was acceptable (9.8±1.52) %. However, the water activity after algae swelling had the highest value of 0.97±0.004, and the swelling coefficient had a relatively low value of 6.5. In further studies, it is planned to study the effect of various methods of algae dehydration on the preservation of its biologically active substances.

Investigation of Infiltration and Runoff Rate on Agri-Mats Using a Laboratory Rainfall Simulation Study

ABSTRACT Soil erosion by water is a major global environmental concern due to its devastating effect on agricultural sustainability and food security. The aim of the current study was to investigate the effectiveness of agri-mats on water erosion control using a laboratory rainfall simulator. Six agri-mat samples were subjected to a runoff and infiltration rate test for this study: three agri-mats were made with 100% dry sugarcane bagasse and the other three agri-mats were made with 10% dry algae +90% dry sugarcane bagasse. The 100% dry sugarcane bagasse agri-mat treatment had higher runoff rate of 16.8 millimeters per hour (mm.hr−1) compared to a mere 1.7 mm.hr−1 recorded under the BA agri-mat during the first 10 min. In addition, the 100% dry sugarcane bagasse agri-mats released magnesium at a rate of 105.7 mg.hr−1 (milligrams per hour) compared to 6.6 mg.hr−1 lost from the 10% dry algae +90% dry sugarcane bagasse agri-mat treatment. Results shows that when algae was used as an additional organic material during the fabrication process, agri-mat delayed runoff by absorbing more moisture than it loses. Algae has the capacity to increase water-holding capacity while improving nutrient status and electrical conductivity of the agri-mats, making them more beneficial not only as the runoff combating technology but as a soil conditioner.

In vitro inhibition of SARS-CoV-2 Infection by dry algae powders

Chlorella spp., Spirulina spp., and fucoidan dry powders, are commercialized as food supplements and are considered safe for human consumption. Their broad-spectrum antiviral properties have been studied, however, their effect against SARS-CoV-2 remains unknown. We investigated the potential antiviral activity of three algae powders: Chlorella vulgaris, Arthrospira maxima (Spirulina) and fucoidan purified from marine brown algae Sargassum spp. against SARS-CoV-2 infection in vitro. Vero cells were incubated with 70 μg/ml of each algae powder and either 50 or 100 TCID50/ml of SARS-CoV-2, in two types of experiments (pretreatment and simultaneous) and comparing two kinds of solvents (DMEM and DMSO). Chlorella vulgaris powder, inhibited SARS-CoV-2 infection in all assays; viral RNA was significantly reduced in supernatants at 24, 48, 72, and 96 h post-infection, the highest difference in viral load (8000-fold) was observed after 96 h. Arthrospira maxima powder inhibited SARS-CoV-2 infection using 50 TCID50/ml for both experimental schemes, but protection percent was lower when viral inoculum was increase to 100 TCID50/ml; viral RNA decreased 48 h after infection, reaching a 250-fold difference at 72 h. Fucoidan powder partially inhibited SARS-CoV-2 infection since no CPE was observed in 62.5% of trated cultures in DMEM, but the antiviral activity was increased to 100% of protection when DMSO was used as solvent. All the algae samples showed high antiviral activity against SARS-CoV-2 with a SI above of 18. These results suggest that all three algae samples are potential therapeutic candidates for the treatment of COVID-19.

Protein Extraction from Spirulina Platensis with The Cellulase Enzyme Assistance

Microalgae is a relatively new, sustainable source of protein supplements. Among various microalgae strains, Spirulina platensis has shown an effective protein potential source compared with others. A high-performance protein recovery technology is required for this prospect. When the cellulase enzyme supported the recovery process, the condition to get the highest protein recovery efficiency (40.13±2.87%) were 50 UI/g dry algae for enzyme activity, 1:20 for the ratio of dry algae: solvent, 7.0 for pH value with a process temperature of 50oC for 90 minutes. This study succeeded in using cellulase enzymes to support protein extraction with high recovery efficiency from Spirulina platensis grown in Vietnam, opening up an additional source of protein in the trend of plant-based meat production.

GC- and UHPLC-MS Profiles as a Tool to Valorize the Red Alga Asparagopsis armata

Asparagopsis armata Harvey is a red alga native from the southern hemisphere and then introduced in the Mediterranean Sea and the Atlantic Ocean, including the Azores Archipelago, where it is considered an invasive alga. Some studies show that the extracts exhibit antimicrobial and antifouling activities, and it is incorporated in some commercialized cosmetic products. (e.g., Ysaline®). However, knowledge of this species chemical composition is scarce. The GC-MS and UHPLC-MS profiles of both the nonpolar and polar extracts were established to contribute to this problem solution. According to the results, A. armata is rich in a great structural variety of halogenated lipophilic and aromatic compounds, some of them identified here for the first time. In the lipophilic extract, 25 compounds are identified, being the halogenated compounds and fatty acids, the two major compound families, corresponding to 54.8% and 35.7% of identified compounds (224 and 147 mg/100 g of dry algae, respectively). The 1,4-dibromobuten-1-ol and the palmitic acid are the two most abundant identified compounds (155 and 83.4 mg/100 g of dry algae, respectively). The polar extract demonstrated the richness of this species in brominated phenolics, from which the cinnamic acid derivatives are predominant. The results obtained herein open new perspectives for valuing the A. armata as a source of halogenated compounds and fatty acids, consequently improving its biotechnological and economic potential. Promoting this seaweed and the consequent increase in its demand will contribute to biodiversity conservation and ecosystem sustainability.

The experimental research of sorption and destruction of diesel fuel by fucus algae of the Barents sea

There was shown the role of live and dry algae Fucus vesiculosus (Phaeophyceae) in the purification of the coastal waters from petroleum products. It was revealed that live algae can be effectively used for preventive, daily purification of marine water, when the content of diesel fuel does not exceed 3 mg/l. For the first time, the prospect of using dry fucus for bioremediation of marine water in emergencies creating a concentration of petroleum products in water of 1 g/l has been determined. In the case of using living plants to neutralize toxicant, the decisive role in the process belongs to the symbiotic association of algae and hydrocarbon-oxidizing bacteria. In case of using dry algae, dried macrophytes become a reservoir for the accumulation of diesel fuel. The main work on the destruction of hydrocarbons, probably, lies on HOB, as well as on physicochemical processes. Metabolic processes inherent in living algae and leading to the destruction of petroleum hydrocarbons weren’t determined in this case.

Assimilation of Particular Organic Matter and Dissolved Organic or Inorganic Compounds by Cribroelphidium selseyense (Foraminifera)

Marine carbon and nitrogen processing through microorganisms’ metabolism is an important aspect of the global element cycles. For that purpose, we used foraminifera to analyze the element turnover with different algae food sources. In the Baltic Sea, benthic foraminifera are quite common and therefore it is important to understand their metabolism. Especially, Cribroelphidium selseyense, also occurring in the Baltic Sea, has often been used for laboratory feeding experiments to test their effect on carbon or nitrogen turnover. Therefore, foraminifera were collected from the Kiel Fjord and fed with six different algal species in two qualities (freeze-dried algae vs. fresh algae, all 13C- and 15N-labeled). Also, labeled dissolved inorganic C and N compounds and glucose were offered to the foraminifera to test direct assimilation of dissolved compounds (carbon and nitrogen) from the water column. Our experiments showed that after 15 days of incubation, there were highly significant differences in isotope labeling in foraminifera fed with fresh algae and dry algae, depending on algal species. Further, different algal species led to different 13C and 15N enrichment in the studied foraminifera, highlighting a feeding preference for one diatom species and an Eustigmatophyte. A significant carbon assimilation from HCO3– was observed after 7 days of incubation. The N assimilation from NH4+ was significantly higher than for NO3– as an inorganic N source. The uptake of glucose showed a lag phase, which was often observed during past experiments, where foraminifera were in a steady state and showed no food uptake at regular intervals. These results highlight the importance of food quality on the feeding behavior and metabolic pathways for further studies of foraminiferal nutrition and nutrient cycling.

Biosorption of chromium by dry algae Chlorella kessleri

Decontamination of environment according to traditional methods is not only economically inaccessible but also often highly environmentally harmful. It is necessary to apply methods that are environmentally friendly as possible. These methods include bioremediation, which uses organisms able to fight with high concentrations of pollutants to decontaminate the environment. In this study, we observed the biosorption of chromium from the aquatic environment using dried algae Chlorella kessleri. The results of the specific sorption at pH = 4.00 in the chromium model sample had a value of q = 5.9 mg / g, which represented a decrease in the chromium concentration by 74%. The specific sorption in the case of the native chromium sample q after 24 hours reached the highest value (q = 2.74 mg / g) at pH = 4.00. During the experiment, we observed a constant change in the content of photosynthetic pigments in the prepared solutions where it was shown that after 24 h exposure the yield of chlorophyll a was decrease by 95.91% compare to control. In the case of chlorophyll b, the same trend was demonstrated where 91.92% decrease of its content after 24 hours was observed. This type of dried alga has been shown to be a rapid biosorbent, in relatively short time intervals. The results of the study show that in the process of decontamination there was not only the binding of chromium to the cell surface but also its penetration through the cell wall.

Marine macrophytes retain microplastics

Microplastics (MPs, 0.2-5 mm) contamination of water outside/inside thickets of macrophytes in the Baltic Sea was studied. The amount of MPs particles in water samples taken within thickets is on average 1.7 times higher than in water samples taken in the areas outside thickets. Fibres are the predominant type of MPs (92.5%). For algae growing on boulders, the abundance of MPs is 1245 ± 1020 items/m2. Per kilogram of dry algae mass the MPs abundance is 376 ± 404 items/kgDW for all shapes of MPs particles. This value is one order of magnitude higher than in sands of the swash zone in the given area. It is shown that filamentous algae retain more fibres than cartilaginous ones: 1.9-8.5 versus 1-1.1 items/l on average. Obviously, areas covered by sea grasses are much more contaminated than water and sediments in the given region.

Nutritional Profiling and Preliminary Bioactivity Screening of Five Micro-Algae Strains Cultivated in Northwest Europe.

This study aimed to map the nutritional profile and bioactivities of five microalgae that can be grown in Northwest Europe or areas with similar cultivation conditions. Next to the biochemical composition, the in vitro digestibility of carbohydrates, proteins, and lipids was studied for Chlamydomonas nivalis, Porphyridium purpureum, Chlorella vulgaris, Nannochloropsis gaditana, and Scenedesmus species biomass. These microalgae were also assessed for their ability to inhibit the angiotensin-1-converting enzyme (ACE-1, EC 3.4.15.1), which is known to play a role in the control of blood pressure in mammals. Large differences in organic matter solubility after digestion suggested that a cell disruption step is needed to unlock the majority of the nutrients from N. gaditana and Scenedesmus species biomass. Significant amounts of free glucose (16.4–25.5 g glucose/100 g dry algae) were detected after the digestion of C. nivalis, P. purpureum, and disrupted Scenedesmus. The fatty acid profiles showed major variations, with particularly high Ω-3 fatty acid levels found in N. gaditana (5.5 ± 0.5 g/100 g dry algae), while lipid digestibility ranged from 33.3 ± 6.5% (disrupted N. gaditana) to 67.1 ± 11.2% (P. purpureum). C. vulgaris and disrupted N. gaditana had the highest protein content (45–46% of dry matter), a nitrogen solubility after digestion of 65–71%, and the degree of protein hydrolysis was determined as 31% and 26%, respectively. Microalgae inhibited ACE-1 by 73.4–87.1% at physiologically relevant concentrations compared to a commercial control. These data can assist algae growers and processors in selecting the most suitable algae species for food or feed applications.

Mycoprotein and hydrophobin like protein produced from marine fungi Paradendryphiella salina in submerged fermentation with green seaweed Ulva spp.

The production of new sources of protein with low environmental impact will guarantee the future of food security. Fungi are gaining importance as a promising source of food protein (mycoprotein) and also have the ability to produce surface-active proteins. This is the first time that the growing of Paradendryphiella salina (marine fungus) on Ulva spp. (green algae) through the submerged liquid fermentation for the production of mycoprotein (from mycelium) and hydrophobin like proteins (from culture broth) is reported. The nutritional composition of mycoprotein was investigated, obtaining a yield of 561.3 g of mycoprotein from 1 kg of dry algae, a good concentration of total protein (48.2 g/100 g), and a considerable concentration of total amino acids (21 g/100 g). The characterization of surface-active protein displays consistent behaviors with the class II hydrophobin. This study proves that sustainable production of mycoproteins and surface-active proteins can be developed growing a marine fungal strain, contributing to shed light on the potentiality of an integrated method that promotes the circular economy.

Fotobiyoreaktörde Işığın ve Beslemenin Alglerin Büyümeleri Üzerine Etkilerinin Araştırılması

The energy and food requirements have been increased depending on the growth of the world populations. The consumption of the food and energy cause for rising the carbon dioxide emissions. The increase of the greenhouse gases develops global warming therefore natural disaster occurred. In order to decrease of the effect of the greenhouse gases, the waste should sustainably be controlled and they should be managed for recycling. In consequence, such as an alternative energy resources biodiesel, wind power, biogas, sun have intensively been investigated. Algaes have been considered as an alternative sources supplier for investigating food stock and energy requirements. Algae is a general definition of organism can make a eukaryotic photosynthesis, and there are many sub-species in this class. In previous studies, 1.83 kg of CO2 have been consumed for production of 1 kg of dry algae and they can be used as fertilizer or bio-oil sources. Therefore, appropriate habitats of Algea along with the various features is necessary to investigate. In this study, the two air bubble column type pilot scale photo-bio reactor 4L were designed for investigation of optimum living condition for "Cladhopora glomerata". Moreover, the effect of different feeding such as inorganic salts, and 17 percent natural amino acids were investigated on the growth of Algea. The results showed that the algae have developed their weight better at the 425 nm wavelength (purple light) compared to daylight. Also, 17 percent natural amino acid is better than the inorganic salts.

PHYSICAL PRETREATMENT OF ULVA FASCIATA FOR ENHANCINGBIODIESEL PRODUCTION AND QUALITY

The green algae Ulva faciata was subjected to different physical pretreatments comprising thermal and mechanical techniques at different experimental conditions to state the most appropriate method of cell disruption for increasing the quantity of the extracted lipid and hence improve the quality of the produced biodiesel with low cost. Thermal pretreatment was autoclaving of either wet or dry algal biomass, while mechanical pretreatments include microwave and ultrasonication at different time intervals. The control was the alga without pretreatment extracted at optimum conditions: 60 min, 55oC, shaking speed at 250 rpm, < 0.16 mm particle size with 25:1 v/w solvent to solid ratio. The results showed that the quantity of extracted lipids in case of using all physical pretreatments increased the Total fatty acids yield significantly by about 2-folds of the control for wet algae in hydrothermal treatment with optimum time of treatment 40 minutes, and 1.4 folds for dry algae in thermal pretreatment of the dried alga for 60minutes autoclaving period. The sharp increase by 2.2 folds of extracted lipids was recorded by microwave pretreatment for radiation period (5 min), while ultrasonication showed 2.1-fold increase in lipid yield at 15minutes ultrasound exposure time. Concerning the physical properties of the produced biodiesel after all physical pretreatments, the results indicated that the produced biodiesel had very high quality as all its properties are almost complied with the ASTM D6751 and EN14214 standards. These results were confirmed statistically where all physical pretreatments had high significant effect on fatty acids yield and Biodiesel properties.