Microalgae biomass cultivation and harvesting optimization in biological carbon capture and utilization systems for biofuels production
Vincenzo SenatoreTiziano ZarraGiuseppina OlivaAntonio BuonerbaPaolo NapodanoVincenzo BelgiornoVincenzo Naddeo
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The boosting of greenhouse gas (GHG) emissions into the atmosphere due to anthropogenic activity contributes significantly to climate change. According to the Green Deal by 2050, net zero greenhouse gas emissions must be achieved. Therefore, actions are needed in order to control GHG emissions. The research presents and discusses the optimization of the microalgae biomass cultivation phase and the harvesting process in an advanced membrane photobioreactor (mPBR) with the aim to improve its production for green fuel generation. Experimental activities are carried out by considering Chlorella vulgaris microalgae as photosynthetic microorganism. A dark/light cycle of 12/12 hours was implemented by varying the light intensity from 100 to 300 μmol m-2 s-1. Different L/G rate, by keeping the gas flow rate (G) constant at 100 ml/min and increasing the liquid flow rate recirculation (L) from 500 to 1500 L min-1, has been tested to boost up the productivity of microalgae. Results highlight optimal production of microalgae biomass concentration up to 1.45 g L-1. Then a dynamic membrane module was implemented for the harvesting of the biomass. The work contributes to the field of climate change mitigation actions, by providing useful information to improve green energy production from algae biomass.Keywords:
Photobioreactor
Chlorella vulgaris
To reduce the level of CO2 content in air, effort on converting CO2 to useful products is required. One of the alternatives includes CO2 fixation to produce biomass using Chlorella vulgaris Buitenzorg. Chlorella vulgaris Buitenzorg is applied for production of food supplement. Chlorella vulgaris Buitenzorg is also easy to handle due to its superior adaptation. Currently, Chlorella vulgaris Buitenzorg has been analyzed by some experts for its cellular composition, its ability to produce high quality biomass and the content of essential nutrition. A series of experiments was conducted by culturing Chlorella vulgaris Buitenzorg using Beneck medium in bubbling column photobioreactor. The main variation in this experiment was photoperiodicity, where growth of Chlorella vulgaris Buitenzorg was examined during photoperiodicity condition. The difference between CO2 gas concentration of inlet and outlet of the reactor during operational period, was compared to the same experiment under continuous illumination. Under photoperiodicity of 8 and 9 h/d, the culture cell densities (N) were approximately 40 % higher than under continuous illumination. Final biomass density of Chlorella vulgaris Buitenzorg at 9 h/d illumination was 1.43 g/dm3, around 46% higher than under continuous illumination. Specific carbon dioxide transfer rate (qCO2) in photoperiodicity was 50-80% higher than under continuous illumination. These experiments showed that photoperiodicity affects the growth of Chlorella vulgaris Buitenzorg The specific growth rate (μ) by photoperiodicity was higher than that by continuous ilumination while the growth period was two times longer. Based on the experiments, it can be concluded that photoperiodicity might save light energy consumption. The prediction of kinetic model under continuous illumination as well as under photoperiodicity illumination showed that Haldane model became the fitted kinetic model.
Chlorella vulgaris
Photobioreactor
Carbon fixation
Light intensity
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Аннотация: Представлено накопительное и непрерывное культивирование микроводоросли Chlorella vulgaris в трубчатом фотобиореакторе.Проведена оценка прироста биомассы по показаниям оптической плотности
Photobioreactor
Chlorella vulgaris
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Photobioreactor
Chlorella vulgaris
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Photobioreactor
Chlorella vulgaris
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Algae bloom in coastal waters is partly supported by residual nutrients in treated wastewater (WW) released from coastally located treatment plants. In response, a Chlorella vulgaris-based photobioreactor was recently proposed for lowering nutrient levels in WW prior to release. However, the solution requires maintaining biomass accumulation to within a photobioreactor capacity for optimum operation. For high density Chlorella vulgaris suspensions, this is easily done by monitoring turbidity increase, a property directly related to biomass accumulation. For low density suspensions however, direct turbidity measurement would require a cumbersome process of concentrating large volumes of Chlorella vulgaris suspensions. Here, we demonstrate that by measuring pH of the suspensions, turbidity (T) can be estimated indirectly by the following wastewater-dependent expression: pH = aT + pH0, hence avoiding the need to concentrate large volumes. The term pH0 is the initial pH of the suspensions and a, a wastewater-dependent constant, can be computed independently from a = - 0.0061*pH0 + 0.052. In the event %WW is unknown, the following wastewater-independent Gaussian expression can be used to estimate T: pH = 8.71*exp(- [(T - 250)2]/[2*1.26E05]). These three equations should offer an avenue for monitoring the turbidity of dilute Chlorella vulgaris suspensions in large, stagnant municipal Chlorella vulgaris-based wastewater treatment system via pH measurements.
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Chlorella vulgaris
Turbidity
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Chlorella vulgaris
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Chlorella vulgaris
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Abstract : The aim of this study is to optimize the efficiency of a photobiorector on the growth rate of Chlorella vulgaris ( C. vulgaris ) by varying distance of optical panel (OP). The round shaped C. vulgaris (FC-16) having the size of 3-8 µm is employed in this study. The cells of C. vulgaris are cultured in the Jaworski’s Medium with deionized water at 22℃ for 15 days. The OP is placed at four different distances i.e., at 225 mm distance (Run 1), 150 mm distance (Run 2), 112.5 mm distance (Run 3) and 90 mm distance (Run 4) having a LED (Light Emitting Diode) source. The diffuse rate is achieved to 86%, 90%, 92% and 94% for Run 1, Run 2 Run 3 and Run 4, respectively. A narrower distance of OP caused to effectively to increase the efficiency of diffuse light rate. For mass cultivation of this biomass, medium is changed according to distance of OP after attaining a maximum biomass concentration; Run 1 in 8 days, Run 2 in 6 days, Run 3 in 4 days and Run 4 in 3 days. In addition, the amount of maxi-mum biomass rate for Run 4 was reached 3 times higher than that of Run1. However, growth rate, chlorophyll per cell, cell volume and doubling time are found to be Run 3 and Run 4 higher than that of Run 1 and Run 2 samples. However, Run 3 and Run 4 are having a slight difference in all these measurements. These findings suggest that in terms of economic consideration and effi-ciency towards simultaneous mass cultivation of biomass, Run 3 was found to be more effective than other samples.
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Chlorella vulgaris
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Photobioreactor
Chlorella vulgaris
Carbon fixation
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Lipid productivity of Chlorella vulgaris and Nannochloropsis oculata was evaluated in a 5 L lab scale externally illuminated photobioreactor. The effect of operating conditions such as pH, temperature, light intensity and photoperiod on biomass productivity, lipid content and lipid productivity was evaluated. At optimum conditions, a maximum lipid productivity of 69.46 and 192.3 mg lipid. L -1 .day- 1 was observed for C.vulgaris and
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