scholarly journals Evaluation of Pre-Chlorinated Wastewater Effluent for Microalgal Cultivation and Biodiesel Production

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 977 ◽  
Author(s):  
Ejovwokoghene Odjadjare ◽  
Taurai Mutanda ◽  
Yi-Feng Chen ◽  
Ademola Olaniran
Keyword(s):  
Total Nitrogen ◽  
Water Footprint ◽  
Oxidation Stability ◽  
Value Added ◽  
Wastewater Effluent ◽  
Biodiesel Production ◽  
Growth Media ◽  
Total Carbohydrate ◽  
Microalgal Biomass ◽  
Microalgal Cultivation

Microalgae are promising feedstock to produce biodiesel and other value added products. However, the water footprint for producing microalgal biodiesel is enormous and would put a strain on the water resources of water stressed countries like South Africa if freshwater is used without recycling. This study evaluates the utilization of pre-chlorinated wastewater as a cheap growth media for microalgal biomass propagation with the aim of producing biodiesel whilst simultaneously remediating the wastewater. Wastewater was collected from two wastewater treatment plants (WWTPs) in Durban, inoculated with Neochloris aquatica and Asterarcys quadricellulare and the growth kinetics monitored for a period of 8 days. The physicochemical parameters; including chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were determined before microalgal cultivation and after harvesting. Total lipids were quantified gravimetrically after extraction by hexane/isopropanol (3:2 v/v). Biodiesel was produced by transesterification and characterised by gas chromatography. The total carbohydrate was extracted by acid hydrolysis and quantified by spectrophotometric method based on aldehyde functional group derivatization. Asterarcys quadricellulare utilized the wastewater for growth and reduced the COD of the wastewater effluent from the Umbilo WWTP by 12.4%. Total nitrogen (TN) and phosphorus (TP) were reduced by 48% and 50% respectively by Asterarcys quadricellulare cultivated in sterile wastewater while, Neochloris reduced the TP by 37% and TN by 29%. Although the highest biomass yield (460 mg dry weight) was obtained for Asterarcys, the highest amount of lipid (14.85 ± 1.63 mg L−1) and carbohydrate (14.84 ± 0.1 mg L−1) content were recorded in Neochloris aquatica. The dominant fatty acids in the microalgae were palmitic acid (C16:0), stearic acid (C18:0) and oleic acid (C18:1). The biodiesel produced was determined to be of good quality with high oxidation stability and low viscosity, and conformed to the American society for testing and materials (ASTM) guidelines.

scholarly journals Optimisation of microalgal cultivation via nutrient-enhanced strategies: the biorefinery paradigm

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Gonzalo M. Figueroa-Torres ◽  
Jon K. Pittman ◽  
Constantinos Theodoropoulos
Keyword(s):  
Kinetic Model ◽  
Growth Dynamics ◽  
Value Added ◽  
Cost Effective ◽  
Predictive Modelling ◽  
Nitrogen And Phosphorus ◽  
Predictive Capacity ◽  
Microalgal Biomass ◽  
Microalgal Cultivation ◽  
Lipid Formation

Abstract Background The production of microalgal biofuels, despite their sustainable and renowned potential, is not yet cost-effective compared to current conventional fuel technologies. However, the biorefinery concept increases the prospects of microalgal biomass as an economically viable feedstock suitable for the co-production of multiple biofuels along with value-added chemicals. To integrate biofuels production within the framework of a microalgae biorefinery, it is not only necessary to exploit multi-product platforms, but also to identify optimal microalgal cultivation strategies maximising the microalgal metabolites from which biofuels are obtained: starch and lipids. Whilst nutrient limitation is widely known for increasing starch and lipid formation, this cultivation strategy can greatly reduce microalgal growth. This work presents an optimisation framework combining predictive modelling and experimental methodologies to effectively simulate and predict microalgal growth dynamics and identify optimal cultivation strategies. Results Microalgal cultivation strategies for maximised starch and lipid formation were successfully established by developing a multi-parametric kinetic model suitable for the prediction of mixotrophic microalgal growth dynamics co-limited by nitrogen and phosphorus. The model’s high predictive capacity was experimentally validated against various datasets obtained from laboratory-scale cultures of Chlamydomonas reinhardtii CCAP 11/32C subject to different initial nutrient regimes. The identified model-based optimal cultivation strategies were further validated experimentally and yielded significant increases in starch (+ 270%) and lipid (+ 74%) production against a non-optimised strategy. Conclusions The optimised microalgal cultivation scenarios for maximised starch and lipids, as identified by the kinetic model presented here, highlight the benefits of exploiting modelling frameworks as optimisation tools that facilitate the development and commercialisation of microalgae-to-fuel technologies.

scholarly journals An Integrated Methodology towards Mitigation of Global Warming and Biomass Production for Biodiesel using Chlorella sorokiniana BTA 9031

2019 ◽  
Vol 8 (4) ◽  
pp. 3054-3058
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Methyl Esters ◽  
Research Work ◽  
Co2 Concentration ◽  
Chlorella Sorokiniana ◽  
Biodiesel Production ◽  
Co2 Absorption ◽  
Microalgal Biomass ◽  
Microalgal Cultivation

The rise of atmospheric carbon dioxide (CO2 )concentration as well as depletion of fossil fuel reserves calls for the development of clean and ecofriendly alternative fuel source. Recently, lipid rich microalgal biomass is being extensively studied for generation of biodiesel however, the expensesincurred on production of microalgal biomassis a significant hurdle. Almost 80 % of the production costis generated from the cultivation medium which majorly comprise of carbon, nitrogen and phosphate. If the microalgal cultivation could be linked to a CO2 capturing unit than the cost of production could be reduced to a large extent. CO2 absorption by means of aqueous amine solvents is known to be a mature technology and could be integrated with microalgal cultivation unit for efficient utilization of the captured CO2 . In this present research work, blended solution of piperazine (PZ) and2-amino2-methyl-1-propanol (AMP) (5/25 wt. %) was used to capture CO2 and then the captured CO2 was utilized as an inorganic carbon stream for growing Chlorella sorokiniana BTA 9031 for biodiesel production. The CO2rate absorption was governed by series of process variablesviz.solvent flow rate ranges (1.5 to 3) ×10⁻4 m 3 min-1 , absorption temperature (298 to 313) K,concentration of CO2 (10 to 15) kPa and gas flow rate(5 to 8) ×10⁻3 m 3 min-1 . The detected final biomass strengthofChlorella sorokiniana BTA 9031 was0.955g L-1 . The fatty acid methyl esters (FAME) determinedsubsequentlyacid transesterification was observed to contain fatty acids suitable for biodiesel production.

scholarly journals Optimisation of Microalgal Cultivation via Nutrient-Enhanced Strategies: the Biorefinery Paradigm

2021 ◽  
Author(s):  
Gonzalo M. Figueroa-Torres ◽  
Jon Pittman ◽  
Constantinos Theodoropoulos
Keyword(s):  
Kinetic Model ◽  
Growth Dynamics ◽  
Value Added ◽  
Cost Effective ◽  
Predictive Modelling ◽  
Nitrogen And Phosphorus ◽  
Predictive Capacity ◽  
Microalgal Biomass ◽  
Microalgal Cultivation ◽  
Lipid Formation

Abstract Background: The production of microalgal biofuels, despite their sustainable and renowned potential, is not yet cost-effective compared to current conventional fuel technologies. However, the biorefinery concept increases the prospects of microalgal biomass as an economically viable feedstock suitable for the co-production of multiple biofuels along with value-added chemicals. To integrate biofuels production within the framework of a microalgae biorefinery, it is not only necessary to exploit multi-product platforms, but also to identify optimal microalgal cultivation strategies maximising the microalgal metabolites from which biofuels are obtained: starch and lipids. Whilst nutrient limitation is widely known for increasing starch and lipid formation, this cultivation strategy can greatly reduce microalgal growth. This work presents an optimisation framework combining predictive modelling and experimental methodologies to effectively simulate and predict microalgal growth dynamics and identify optimal cultivation strategies. Results: Microalgal cultivation strategies for maximised starch and lipid formation were successfully established by developing a multi-parametric kinetic model suitable for the prediction of mixotrophic microalgal growth dynamics co-limited by nitrogen and phosphorus. The model’s high predictive capacity was experimentally validated against various datasets obtained from laboratory-scale cultures of Chlamydomonas reinhardtti CCAP 11/32C subject to different initial nutrient regimes. The identified model-based optimal cultivation strategies were further validated experimentally and yielded significant increases in starch (+270 %) and lipid (+74 %) production against a non-optimised strategy. Conclusions: The optimised microalgal cultivation scenarios for maximised starch and lipids, as identified by the kinetic model presented here, highlight the benefits of exploiting modelling frameworks as optimisation tools that facilitate the development and commercialisation of microalgae-to-fuel technologies.

scholarly journals Lab-scale assessment and adaptation of wastewater for cultivation of microalgal biomass for biodiesel production

2015 ◽  
Author(s):  
◽  
Luveshan Ramanna
Keyword(s):  
Large Scale ◽  
Physiological Stress ◽  
Lipid Production ◽  
Domestic Wastewater ◽  
Potassium Nitrate ◽  
Wastewater Effluent ◽  
Biodiesel Production ◽  
Available Nitrogen ◽  
Microalgal Biomass ◽  
Microalgal Culture

In light of the world’s declining fossil fuel reserves, the use of microalgal biodiesel has come to the forefront as a potentially viable alternative liquid fuel. The depleting freshwater reserves make the feasibility of this concept questionable. The use of wastewater reduces the requirement for depleting freshwater supplies. This project aimed to determine the viability of municipal domestic wastewater effluent as a substrate for microalgal growth, in order to generate an economical and environmentally friendly source of biofuel. Wastewater effluents from three domestic wastewater treatment plants were characterized in terms of known microalgal nutrients viz., ammonia, phosphate and nitrates. Phosphate concentrations varied throughout the year and were found to be low (< 3 mgL-1) whilst ammonia and nitrate concentrations ranged from 0 to 10 mgL-1 throughout the experimental period. These wastewaters were found to be suitable for cultivating microalgae. The study explored the cultivation of Chlorella sorokiniana on pre- and post-chlorinated domestic wastewater effluent to assess their potential as a medium for high microalgal culture density and lipid production. Post-chlorinated wastewater effluent was found to be superior to pre-chlorinated wastewater effluent, as evident by the higher biomass concentration. This wastewater stream did not contain high concentrations of bacteria when compared to pre-chlorinated wastewater effluent. Nitrogen is an essential nutrient required for regulating the growth and lipid accumulation in microalgae. Cultures growing in post-chlorinated effluent had a lifespan of 18 d. Residual nitrogen in wastewater effluent supported microalgal growth for limited periods. Supplementation using cheap, readily available nitrogen sources was required for optimal biomass and lipid production. Urea, potassium nitrate, sodium nitrate and ammonium nitrate were evaluated in terms of biomass and lipid production of C. sorokiniana. Urea showed the highest biomass yield of 0.216 gL-1 and was selected for further experimentation. Urea concentrations (0–10 gL-1) were assessed for their effect on growth and microalgal physiology using pulse amplitude modulated fluorometry. A concentration of 1.5 gL-1 urea produced 0.218 gL-1 biomass and 61.52 % lipid by relative fluorescence. Physiological stress was evident by the decrease in relative Electron Transport Rate from 10.45 to 6.77 and quantum efficiency of photosystem II charge separation from 0.665 to 0.131. Gas chromatography analysis revealed that C16:0, C18:0, C18:1, C18:2 and C18:3 were the major fatty acids produced by C. sorokiniana. Wastewater effluent has been considered an important resource for economical and sustainable microalgal biomass/lipid production. The study showed that C. sorokiniana was sufficiently robust to be cultivated on wastewater effluent supplemented with urea. The results indicate that supplemented wastewater effluent was an acceptable alternative to conventional media. Using a relatively cheap nitrogen source like urea can certainly improve the techno-economics of large scale biodiesel production.

scholarly journals Valorization of Wastewater Resources Into Biofuel and Value-Added Products Using Microalgal System

2021 ◽  
Vol 9 ◽  
Author(s):  
Kanika Arora ◽  
Parneet Kaur ◽  
Pradeep Kumar ◽  
Archana Singh ◽  
Sanjay Kumar Singh Patel ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Industrial Wastewater ◽  
Microbial Growth ◽  
Oxygen Demand ◽  
Value Added ◽  
Aquatic Organisms ◽  
Pilot Scale ◽  
Microalgal Biomass ◽  
Microalgal Cultivation ◽  
Value Added Products

Wastewater is not a liability, instead considered as a resource for microbial fermentation and value-added products. Most of the wastewater contains various nutrients like nitrates and phosphates apart from the organic constituents that favor microbial growth. Microalgae are unicellular aquatic organisms and are widely used for wastewater treatment. Various cultivation methods such as open, closed, and integrated have been reported for microalgal cultivation to treat wastewater and resource recovery simultaneously. Microalgal growth is affected by various factors such as sunlight, temperature, pH, and nutrients that affect the growth rate of microalgae. Microalgae can consume urea, phosphates, and metals such as magnesium, zinc, lead, cadmium, arsenic, etc. for their growth and reduces the biochemical oxygen demand (BOD). The microalgal biomass produced during the wastewater treatment can be further used to produce carbon-neutral products such as biofuel, feed, bio-fertilizer, bioplastic, and exopolysaccharides. Integration of wastewater treatment with microalgal bio-refinery not only solves the wastewater treatment problem but also generates revenue and supports a sustainable and circular bio-economy. The present review will highlight the current and advanced methods used to integrate microalgae for the complete reclamation of nutrients from industrial wastewater sources and their utilization for value-added compound production. Furthermore, pertaining challenges are briefly discussed along with the techno-economic analysis of current pilot-scale projects worldwide.

scholarly journals OPPORTUNITIES FOR REDUCTION OF ENERGY CONSUMPTION IN THE LIFE CYCLE OF BIODIESEL OBTAINED FROM MICROALGAE SCENEDESMUS SP.

2014 ◽  
Vol 46 (1) ◽  
pp. 94-103
Author(s):  
Virginija Skorupskaite ◽  
Violeta Makareviciene
Keyword(s):  
Life Cycle ◽  
Energy Consumption ◽  
Biodiesel Production ◽  
Growth Media ◽  
Total Energy Consumption ◽  
Microalgal Biomass ◽  
Microalgae Oil ◽  
Reduction Of Energy Consumption ◽  
Fossil Energy Ratio ◽  
Liquid Biofuel

The article considers the opportunities for reduction of energy consumption in the life cycle of biodiesel obtained from microalgae oil. Results show that by introducing technical glycerol and substrate leftover after production of biogas into the microalgae growth media energy consumption can be significantly reduced. Production of biogas from de-oiled microalgae improves the energy balance of the life cycle of biodiesel obtained from microalgae oil. It is impossible to obtain fuel containing more energy than would be used in the process of production if microalgae for biodiesel production are cultivated in conventional growth media. Only by subjecting microalgal biomass for production of gaseous and liquid biofuel (biodiesel and biogas) the total energy consumption is lower and equals to 65802.03 MJt-1 than energy value of biofuel, i.e. 79083.32 MJt-1. In this case the fossil energy ratio (FER) for biodiesel reaches 1.2.

scholarly journals Solvent-Free Benzylation of Glycerol by Benzyl Alcohol Using Heteropoly Acid Impregnated on K-10 Clay as Catalyst

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
Devendra P. Tekale ◽  
Ganapati D. Yadav ◽  
Ajay K. Dalai
Keyword(s):  
Heterogeneous Catalysis ◽  
Benzyl Alcohol ◽  
Batch Reactor ◽  
Value Added ◽  
Solvent Free ◽  
Biodiesel Production ◽  
Area Measurement ◽  
Solid Catalyst ◽  
Glycerol Ether ◽  
Insight Into

Value addition to glycerol, the sole co-product in biodiesel production, will lead to reform of the overall biodiesel economy. Different valuable chemicals can be produced from glycerol using heterogeneous catalysis and these valuable chemicals are useful in industries such as cosmetics, pharmaceuticals, fuels, soap, paints, and fine chemicals. Therefore, the conversion of glycerol to valuable chemicals using heterogeneous catalysis is a noteworthy area of research. Etherification of glycerol with alkenes or alcohols is an important reaction in converting glycerol to various value-added chemicals. This article describes reaction of glycerol with benzyl alcohol in solvent-free medium by using a clay supported modified heteropolyacid (HPA), Cs2.5H0.5PW12O40/K-10 (Cs-DTP/K-10) as solid catalyst and its comparison with other catalysts in a batch reactor. Mono-Benzyl glycerol ether (MBGE) was the major product formed in the reaction along with formation of di-benzyl glycerol ether (DBGE). The effects of different parameters were studied to optimize the reaction parameters. This work provides an insight into characterization of Cs2.5H0.5PW12O40/K-10 catalyst by advanced techniques such as surface area measurement, X-ray analysis, ICP-MS, FT-IR, and SEM. Reaction products were characterized and confirmed by using the GCMS method. The kinetic model was developed from an insight into the reaction mechanism. The apparent energy of activation was found to be 18.84 kcal/mol.

scholarly journals Optimizing the catalytic activities of methanol and thermotolerant Kocuria flava lipases for biodiesel production from cooking oil wastes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Azhar Najjar ◽  
Elhagag Ahmed Hassan ◽  
Nidal Zabermawi ◽  
Saber H. Saber ◽  
Leena H. Bajrai ◽  
...  
Keyword(s):  
Ph Value ◽  
Energy Content ◽  
Value Added ◽  
Relative Activity ◽  
Economic Feasibility ◽  
Biodiesel Production ◽  
Molar Ratios ◽  
Cooking Oil ◽  
Enzyme Biocatalysis ◽  
Methanol Tolerant

AbstractIn this study, two highly thermotolerant and methanol-tolerant lipase-producing bacteria were isolated from cooking oil and they exhibited a high number of catalytic lipase activities recording 18.65 ± 0.68 U/mL and 13.14 ± 0.03 U/mL, respectively. Bacterial isolates were identified according to phenotypic and genotypic 16S rRNA characterization as Kocuria flava ASU5 (MT919305) and Bacillus circulans ASU11 (MT919306). Lipases produced from Kocuria flava ASU5 showed the highest methanol tolerance, recording 98.4% relative activity as well as exhibited high thermostability and alkaline stability. Under the optimum conditions obtained from 3D plots of response surface methodology design, the Kocuria flava ASU5 biocatalyst exhibited an 83.08% yield of biodiesel at optimized reaction variables of, 60 ○C, pH value 8 and 1:2 oil/alcohol molar ratios in the reaction mixture. As well as, the obtained results showed the interactions of temperature/methanol were significant effects, whereas this was not noted in the case of temperature/pH and pH/methanol interactions. The obtained amount of biodiesel from cooking oil was 83.08%, which was analyzed by a GC/Ms profile. The produced biodiesel was confirmed by Fourier-transform infrared spectroscopy (FTIR) approaches showing an absorption band at 1743 cm−1, which is recognized for its absorption in the carbonyl group (C=O) which is characteristic of ester absorption. The energy content generated from biodiesel synthesized was estimated as 12,628.5 kJ/mol. Consequently, Kocuria flava MT919305 may provide promising thermostable, methanol-tolerant lipases, which may improve the economic feasibility and biotechnology of enzyme biocatalysis in the synthesis of value-added green chemicals.

Effect of Silicon Carbide Susceptor and Nickel Catalyst Content on Microwave Enhanced Thermal Conversion of Glycerol Waste

2010 ◽  
Vol 658 ◽  
pp. 73-76
Author(s):  
Yotwadee Hawangchu ◽  
Duangduen Atong ◽  
Viboon Sricharoenchaikul
Keyword(s):  
Silicon Carbide ◽  
Nickel Catalyst ◽  
Fixed Bed ◽  
Value Added ◽  
Thermal Conversion ◽  
Gas Production ◽  
Biodiesel Production ◽  
Spent Catalyst ◽  
Catalyst Content ◽  
Transesterification Method

Glycerol waste is by-product from the manufacturing of biodiesel by transesterification method containing impurities such as fatty acid, alcohol, spent catalyst, soap and water. Conversion of this waste to value added fuel products would not only improve economic of biodiesel production but also reduce environmental impact from this process. In this work, thermal conversion of glycerol waste by microwave that induced the heat required for initiating the reaction was carried out in a fixed bed quartz reactor using silicon carbide as the bed medium for microwave receptor as well as supporter for nickel catalyst. For non-catalytic reaction at 220W (700°C), carbon and hydrogen conversions were 22.89% and 19.59%, respectively. Gas production was 0.12 L/min syngas, 0.07 L/min H2, 0.82 MJ/m3 of LHV, and 1.27 H2/CO. In catalytic test, the highest syngas, H2, and LHV of 0.41 L/min, 0.23 L/min, and 9.18 MJ/m3, respectively, were obtained from 1%Ni/SiC while the highest H2/CO of 2.72 was obtained from 0.5%Ni/SiC. The 1%Ni/SiC test also resulted in the highest conversion of carbon and hydrogen as much as 79.50% and 83.26%, respectively. For comparison between fresh and regenerated catalysts, it was found that fresh catalyst performed significantly better that regenerated one in term of higher total conversion which may due to sodium deposition on spent catalyst surface.

scholarly journals Physical Methods of Microalgal Biomass Pretreatment

2014 ◽  
Vol 28 (3) ◽  
pp. 341-348 ◽  
Author(s):  
Agata Piasecka ◽  
Izabela Krzemińska ◽  
Jerzy Tys
Keyword(s):  
Alternative Energy ◽  
Lipid Extraction ◽  
Physical Method ◽  
Extraction Methods ◽  
Biodiesel Production ◽  
Biomass Pretreatment ◽  
Microalgal Biomass ◽  
Alternative Energy Sources ◽  
Wet Biomass ◽  
Microwave Techniques

Abstract The prospect of depletion of natural energy resources on the Earth forces researchers to seek and explore new and alternative energy sources. Biomass is a composite resource that can be used in many ways leading to diversity of products. Therefore, microalgal biomass offers great potential. The main aim of this study is to find the best physical method of microalgal biomass pretreatment that guarantees efficient lipid extraction. These studies identifies biochemical composition of microalgal biomass as source for biodisel production. The influence of drying at different temperatures and lyophilization was investigated. In addition, wet and untreated biomass was examined. Cell disruption (sonication and microwave) techniques were used to improve lipid extraction from wet biomass. Additionally, two different extraction methods were carried out to select the best method of crude oil extraction. The results of this study show that wet biomass after sonication is the most suitable for extraction. The fatty acid composition of microalgal biomass includes linoleic acid (C18:2), palmitic acid (C16:0), oleic acid (C18:1), linolenic acid (C18:3), and stearic acid (C18:0), which play a key role in biodiesel production.

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