A protocol is described to utilize the carbon dioxide in natural gas power plant flue gas to cultivate microalgae in open raceway ponds. Flue gas injection is controlled with a pH sensor, and microalgae growth is monitored with real time measurements of optical density.
In the United States, 35% of the total carbon dioxide (CO2) emissions come from the electrical power industry, of which 30% represent natural gas electricity generation. Microalgae can biofix CO2 10 to 15 times faster than plants and convert algal biomass to products of interest, such as biofuels. Thus, this study presents a protocol that demonstrates the potential synergies of microalgae cultivation with a natural gas power plant situated in the southwestern United States in a hot semi-arid climate. State-of-the-art technologies are used to enhance carbon capture and utilization via the green algal species Chlorella sorokiniana, which can be further processed into biofuel. We describe a protocol involving a semi-automated open raceway pond and discuss the results of its performance when it was tested at the Tucson Electric Power plant, in Tucson, Arizona. Flue gas was used as the main carbon source to control pH, and Chlorella sorokiniana was cultivated. An optimized medium was used to grow the algae. The amount of CO2 added to the system as a function of time was closely monitored. Additionally, other physicochemical factors affecting algal growth rate, biomass productivity, and carbon fixation were monitored, including optical density, dissolved oxygen (DO), electroconductivity (EC), and air and pond temperatures. The results indicate that a microalgae yield of up to 0.385 g/L ash-free dry weight is attainable, with a lipid content of 24%. Leveraging synergistic opportunities between CO2 emitters and algal farmers can provide the resources required to increase carbon capture while supporting the sustainable production of algal biofuels and bioproducts.
Global warming is one of the most important environmental issues that the world faces today1. Studies suggest that the major cause is the increase in greenhouse gas (GHG) emissions, mainly CO2, in the atmosphere due to human activities2,3,4,5,6,7. In the U.S., the largest density of CO2 emissions originates mainly from fossil fuel combustion in the energy sector, specifically electric power generation plants3,7,8,9. Thus, carbon capture and utilization (CCU) technologies have emerged as one of the major strategies to reduce GHG emissions2,7,10. These include biological systems that utilize sunlight to convert CO2 and water via photosynthesis, in the presence of nutrients, to biomass. The use of microalgae has been proposed due to the fast growth rate, high CO2 fixation ability, and high production capacity. Additionally, microalgae have broad bioenergy potential because the biomass can be converted into products of interest, such as biofuels that can replace fossil fuels7,9,10,11,12.
Microalgae can grow and achieve biological conversion in a variety of cultivation systems or reactors, including open raceway ponds and closed photobioreactors13,14,15,16,17,18,19. Researchers have studied the advantages and limitations that determine the success of the bioprocess in both cultivation systems, under either indoor or outdoor conditions5,6,16,20,21,22,23,24,25. Open raceway ponds are the most common cultivation systems for carbon capture and utilization in situations where flue gas can be distributed directly from the stack. This type of cultivation system is relatively inexpensive, is easy to scale up, has low energy costs, and has low energy requirements for mixing. Additionally, these systems can easily be co-located with the power plant to make the CCU process more efficient. However, there are some drawbacks that need to be considered, such as the limitation in CO2 gas/liquid mass transfer. Although there are limitations, open raceway ponds have been proposed as the most suitable system for outdoor microalgal biofuel production5,9,11,16,20.
In this article, we detail a method for microalgae cultivation in open raceway ponds that combines carbon capture from the flue gas of a natural gas power plant. The method consists of a semi-automated system that controls flue gas injection based on the culture pH; the system monitors and records the Chlorella sorokiniana culture status in real time using optical density, dissolved oxygen (DO), electroconductivity (EC), and air and pond temperature sensors. Algal biomass and flue gas injection data are collected by a data logger every 10 min at the Tucson Electric Power facility. Algae strain maintenance, scale up, quality control measurements, and biomass characterization (e.g., correlation between optical density, g/L, and lipid content) are performed in a laboratory setting at the University of Arizona. A previous protocol outlined a method for optimizing flue gas settings to promote microalgae growth in photobioreactors via computer simulation26. The protocol presented here is unique in that it utilizes open raceway ponds and is designed to be implemented on-site at a natural gas power plant in order to make direct use of the flue gas produced. Additionally, real time optical density measurements are part of the protocol. The system as described is optimized for a hot semiarid climate (Köppen BSh), which exhibits low precipitation, significant variability in precipitation from year to year, low relative humidity, high evaporation rates, clear skies, and intense solar radiation27.
1. Growth system: outdoor open raceway pond settings
2. pH control system
3. Algae selection and strain maintenance (light and temperature)
NOTE: The green algae Chlorella sorokiniana DOE 1412 was isolated by Juergen Polle (Brooklyn College)30,31 and selected by the National Alliance for Advanced Biofuels and Bioproducts (NAABB); its selection was based on the previous strain characterization studies performed by Huesemann et al.32,33 . Their research regarding algal screening, biomass productivity, and climate-simulated culturing (e.g., temperature and light) in the Southwest region when using outdoor open raceway ponds informed the method used in this project.
4. Scale up and quality control
5. Concentrated medium preparation for open pond cultivation
6. Outdoor open raceway pond inoculation
7. Batch growth experiment at the generating station
8. Discrete sampling and monitoring
9. Algal harvesting and crop rotation
10. Data management
Prior experimental results from our lab indicate that microalgae cultivation using a semi-automated open raceway pond can be coupled with carbon capture processes. To better understand the synergy between these two processes (Figure 2), we developed a protocol and tailored it for cultivating the green algal species Chlorella sorokiniana under outdoor conditions in a hot semiarid climate. Natural gas flue gas was obtained from an industrial power generation station. This protocol uses various technologies to assess algal biomass productivity: (1) algae growth using a real time optical density sensor (Figure 5); (2) algae growth with respect to flue gas on-off pulse injections into the culture as a function of pH (Figure 6 and Figure 7); and (3) algae growth correlations with environmental parameters such as temperature, dissolved oxygen, and electroconductivity (Figure 8 and Figure 9).
We test a real time optical density sensor that monitors algae growth and physiological dynamics. This sensor allowed us to establish, via lab correlation, the corresponding ash free dry weight biomass (g/L). Figure 5 shows a comparison between the sensor and laboratory measurements. Both readings show similar trends, increasing as a function of time. However, the in-situ sensor readings can track the day/night algae growth cycle. Said cycle shows that the optical density values increase during the day but decrease at night during respiration, indicating a change in biomass productivity. The integration of the real time optical density sensor makes it possible to make effective management decisions about the overall algal production system.
We deploy a semi-automated on-off flue gas pulse injection system, which is represented in Figure 6 by a 24 h flue gas injection cycle measured during a particularly warm fall season in Tucson, AZ. As shown in Figure 6, flue gas was injected from approximately 8 am to 6 pm (diurnal period) but was not injected between 6 pm and 8 am (nocturnal period). This day/night cycle reflects the daily sunlight exposure and the lack of light during the night, and consequently, the activation of photosynthesis or photorespiration, respectively. Figure 7 presents the cumulative flue gas injected (L) during this algal batch. In this case, 6,564 L of flue gas, corresponding to 538 L CO2, were used to grown 0.29 g of algal biomass. The graph shows that as the algal growth rate increased, more flue gas (CO2) was required (Figure 6). The experimental results have confirmed that the on-off flue gas pulse injection system is effective at facilitating carbon capture and utilization through microalgae cultivation.
We measure and monitor other physicochemical parameters to establish a correlation between them and algal growth and productivity (Figure 8 and Figure 9). The environmental parameters measured were dissolved oxygen, electroconductivity (EC), and both air and pond temperatures. As expected, all the parameters, except EC, displayed similar trends that were highly correlated with solar radiation. The results indicate that these environmental variables had the most significant impact on algal growth and are used for algal biomass modeling35. The EC did not change significantly during the batch process. Thus, it did not provide any relevant information regarding algal growth. For cultivation of Chlorella sorokiniana using non-saline water, EC measurements can be omitted.
Figure 1: Pilot site location at Tucson Electric Power for coupling carbon capture from power plant and semi-automatized open-pond reactors for microalgae cultivation. The two locations are represented by: 1) Algae Site U3 (unit 3) and 2) Algae Site U4 (unit 4) photo credit: Jose Manuel Cisneros Vazquez. Please click here to view a larger version of this figure.
Figure 2: Process flow chart for coupling carbon capture and semi-automatized open raceway ponds for microalgae cultivation in a hot semiarid climate. (A) Open Raceway Paddlewheel design; (B) Real experimental facility; (C) Process: coupling carbon capture and microalgae cultivation modified from Van Den Hende28. Legends: T = Temperature; DO = Dissolved oxygen; OD = Optical density; EC = Electrical conductivity; Data Logger. Please click here to view a larger version of this figure.
Figure 3: Schematic representation of sensor set up. (A) Representation of the overall outdoor open-pond sensors set up, in which CV1 and CV2 are the control valves, DL is the data logger, and T1 and T2 are the transmitters. (B) Representation of a control valve. (C) Representation of the sensors’ connection to the data logger; dark blue circle: real time optical density, orange triangle: pH and EC, black triangle: thermocouples, red triangle: dissolved oxygen, light blue: control valve. (D) pH and EC transmitter. Please click here to view a larger version of this figure.
Figure 4: Algae under the acclimation process. Microalgae acclimation strategy using wooden pallets during the exponential phase. Please click here to view a larger version of this figure.
Figure 5: Representation of algae growth monitoring. (A) Graph for AFDW biomass concentration (g/L) vs. time of laboratory measurements; (B) Graph for correlation between optical density sensor and laboratory measurements at 650 nm; and (C) graph for real time optical density sensor vs time for an experimental batch. Please click here to view a larger version of this figure.
Figure 6: Graph for on/off flue gas pulse injection as a fuction of pH. The data logger was set up to start flue gas injection (controlled valve on) at pH = 8.05 and to end flue gas injection (controlled valve off) at pH = 8.00. Please click here to view a larger version of this figure.
Figure 7: Graph for algal growth (g/L), amount of flue gas injected, and amount of CO2 injected as a function of time. Please click here to view a larger version of this figure.
Figure 8: Representation of temperature monitoring. Legends: solid yellow line = raceway pond reactor temperature; solid grey line = air temperature; and dashed blue line = AZMET Station temperature (The Arizona Meteorological Network). Please click here to view a larger version of this figure.
Figure 9: Monitoring of algae growth parameters. Legends: orange solid line = solar radiation; grey solid line = electroconductivy (EC); and yellow solid line = dissolved oxygen (DO). Please click here to view a larger version of this figure.
Components | Concentration in solution (g/L) |
H3BO3 | 0.00286 |
MnCl2·4H2O | 0.00181 |
ZnSO4·7H2O | 0.0001373 |
Na2MoO4·2H2O | 0.00039 |
CuSO4·5H2O | 0.000079 |
Co(NO3)2·6H2O | 0.00005518 |
NiCl2·6 H2O | 0.0001 |
Table 1: Trace elements solution recipe.
Components | Common name | Concentration in solution (g/L) |
(NH2)2CO | Urea | 0.1 |
MgSO4·7H2O | Magnesium Sulfate | 0.012 |
NH4H2PO4 | Ammonium Phosphate | 0.035 |
KCl | Potash | 0.175 |
FeCl3 | Ferric Citrate (Citraplex) | 0.005423 |
Trace Metal Solution | Volume of 1000x Micros (ml) | 1 |
Table 2: Optimized media recipe for 1 L.
Supplemental Coding Files. Please click here to download this file.
In this study, we demonstrate that synergistically coupling flue gas carbon capture and microalgae cultivation is possible in a hot semi-arid climate. The experimental protocol for the semi-automated raceway pond system integrates state-of-the-art technology to monitor relevant parameters in real time that correlate to algal growth when using flue gas as a carbon source. The proposed protocol is intended to reduce uncertainty in algal cultivation, which is one of the main drawbacks of raceway ponds20,21,36. In our experience, the protocol’s most critical steps involve the pH control system and an effective method to inoculate the system (Figure 2). The pH control system delivers flue gas/CO2 and represents a strategy to optimize efficiency in CO2 capture and utilization (Figure 3)37. This controlled system has been proven to be more efficient than a continuous injection system for the microalgae cultivation process because it reduces outgassing while delivering enough flue gas to attain the maximum algal growth rate20,37. When the flue gas injection is based on pH, a key factor for algal cultivation is selecting an adequate pH value for the microalgae species before inoculating the raceway pond38,39. Qiu et al.40 found that a pH value of 8 is the best for the freshwater species Chlorella sorokiniania when considering cell growth and lipid production40. Moreover, Molina Grima et al.41 recommend a pH below 8 to reduce nitrogen loss and achieve better nitrogen uptake by the microalgae/biomass41. However, Yuvraj et al.42 suggest that pH is not an appropriate method to evaluate the CO2 content in the water because of the effect of nitrogen fertilization on the medium’s acidity42. Our results show that pH can be effectively used to manage CO2 injection for the system presented here (Figure 6); our flue gas injection management, which kept the culture at pH 8, resulted in high biomass yields and replicability (Figure 7).
After inoculation, the algae must acclimate to the system to avoid photoinhibition and to adjust to the high temperature of the raceway media. In this hot semi-arid climate, we have observed algal photoinhibition due to high solar radiation39,43,44 (Figure 9). This effect can not only delay but also inhibit microalgae inoculation during the exponential phase32,35,45,46,47. To reduce the impact of acclimation on the microalgae, we designed a successful and feasible strategy consisting of partially shading the raceway pond with wooden pallets. This strategy allows the microalgae to be exposed repeatedly but for short periods of time to the solar conditions. Another stress factor is the high temperature of the flue gas and the ambient air33,48 (Figure 8). The flue gas temperature is quite high at the post-combustion stage10,48,49. Utilizing the flue gas by directly injecting it from the dispatched pipeline into the raceway pond can contribute to further increasing the medium’s temperature. Hence, a condenser followed by a water trap located before the compressor will not only reduce the heat transfer but also the amount of water reaching the compressor (Figure 2). We found that both devices were necessary to reduce the compressor failure rate. Additionally, humidity, flue gas temperature, and the corrosive nature of the flue gas must be considered when estimating the compressor’s life cycle and maintenance. Furthermore, high temperatures cause higher evaporation rates.
This protocol is subject to some limitations. According to Figure 6, the control valve was not able to inject enough flue gas when photosynthesis was at its peak. This effect can be attributed to low mass transfer from the gaseous to the liquid phase due to the reactor design5,16,50,51. Mendoza et al.36,52 and de Godos et al.16 stated that raceway ponds have a poor gas/liquid mass transfer, which represents one of the most severe design constraints16,36,52. Their shallow channel design limits CO2 mass transfer due to the short interface area between the gas and the culture medium, which causes an increase in CO2 off-gassing (Figure 2). Thus, devices and novel configurations have been proposed to increase the gas/liquid contact time, including sumps, mixing columns, permeable silicone, and sparging-diffusion systems36,52,53. All these systems have been used in an attempt to enhance CO2 mass transfer; however, some of these systems also improve nutrient distribution, control pH, and remove excess O25,24,36,52. Finally, outages are other limitations that can arise when capturing and utilizing real flue gas from a power plant. These outages are not always scheduled. Thus, temporary alternative sources of CO2 should be considered, for example, relocation or connecting the CO2 mainline to multiple power units (Figure 1).
The ability to produce microalgae with this protocol is supported by our results on algal productivity (Figure 5), algal responses to the selected parameters (Figure 6, Figure 8, Figure 9), and successful cultivation of the desired algal species when nurtured by direct flue gas injection. Open reactors are cheaper to operate, and thus, this protocol builds upon their strengths to accelerate commercial-scale deployment of this form of carbon capture and utilization16,20,54,55,56. This hot semi-arid region experiences high solar radiation and significant temperature fluctuations year-round (Figure 8 and Figure 9)57; hence, it is a prime location to test this sort of protocol. The optical density sensor provided consistent OD readings for our outdoor open system (Figure 5); this type of data collection would be impractical using other sensors. Also, the sensors responded well to the significant temperature variations from day to night (Figure 8), enabling us to make timely algal productivity decisions29. Furthermore, the proposed optimized medium has the critical advantage of being based on commercial fertilizer and readily available nutrient sources58 (Table 1 and 2); this medium can be easily produced in-house or could be sourced upon request from agricultural liquid fertilizer companies58. Finally, the semi-automated protocol was tested in an additional natural gas power plant. The results of that confirmation study are not presented in this paper. In that confirmation study, the protocol was successful despite the extreme weather conditions in Tucson and the exceptionally hot temperatures at the generation station due to the reactor’s location within the power plant layout. Therefore, protocol replicability has been examined for Tucson’s environment when natural gas is used as fuel to produce electricity.
The following steps are recommended to further develop this protocol and to improve and enhance the automation of the processes involved. The first recommendation is to make the flue gas injection a completely variable-rate process, thus improving CO2 and pH management; the current program fully opens the injection valve when the pH rises above 8 and closes it when the pH reaches 8 again. Improving the way CO2 is injected is also necessary. The aim is to reduce the size of the CO2 bubbles, i.e., to generate microbubbles to enhance CO2 diffusion in the medium without resorting to injecting flue gas at higher pressure. Using improved injectors, thus reducing operational energy costs, is deemed necessary in a commercial application of the protocol. The inclusion of predictive tools based on the weather forecast and current microalgae status for controlling the flue gas and fertilizer, mainly N, to improve N use efficiency, is also recommended. The use of computational fluid dynamic modeling is considered a vital tool in developing the proposed protocol further; modeling can help optimize the design, configuration, and operation of all the hardware involved in the monitoring and management of the microalgae. Another area that could be explored in the future is the application of environmental DNA (eDNA) and real time PCR techniques to monitor the health and composition of the microalgae crop. Water samples could be analyzed, and the results would indicate whether the objective microalgae are the predominant species in the medium or whether it is competing or has been replaced by a different organism.
The authors have nothing to disclose.
This work was supported through the Regional Algal Feedstock Testbed project, U.S. Department of Energy DE-EE0006269. We also thank Esteban Jimenez, Jessica Peebles, Francisco Acedo, Jose Cisneros, RAFT Team, Mark Mansfield, UA power plant staff, and TEP power plant staff for all their help.
Adjustable speed motor (paddle wheel system) | Leeson | 174307 | Lesson 174307.00, type: SCR Voltage; Amps:10 |
Aluminum weight boats | Fisher Scientific | 08-732-102 | Fisherbrand Aluminum Weighing Dishes |
Ammonium Iron (III) (NH₄)₅[Fe(C₆H₄O₇)₂] | Fisher Scientific | 1185 – 57 – 5 | Medium preparation. Ammonium iron(III) citrate |
Ammonium Phosphate | Sigma-Aldrich | 7722-76-1 | This chemical is used for the optimized medium |
Ampicillin sodium salt | Sigma Aldrich | A9518-5G | This chemical is used for avoiding algae contamination |
Autoclave | Amerex Instrument Inc | Hirayama HA300MII | |
Bacto agar | Fisher Scientific | BP1423500 | Fisher BioReagents Granulated Agar |
Bleach | Clorox | Germicidal Bleach, concentrated clorox | |
Boric Acid (H3BO3) | Fisher Scientific | 10043-35-3 | Trace Elelements: Boric acid |
Calcium chloride dihydrate (CaCl2*2H2O) | Sigma-Aldrich | 10035-04-8 | Medium preparation. Calcium chloride dihydrate |
Carboys (20 L) | Nalgene – Thermo Fisher Scientific | 2250-0050PK | Polypropylene Carboy w/Handles |
Centrifuge | Beckman Coulter, Inc | J2-21 | |
Chloroform | Sigma-Aldrich | 67-66-3 | This chemical is used for lipid extraction |
Citraplex 20% Iron | Loveland Products | SDS No. 1000595582 -17-LPI | https://www.fbn.com/direct/product/Citraplex-20-Iron#product_info |
Cobalt (II) nitrate hexahydrate (Co(NO3)2*6H2O) | Sigma-Aldrich | 10026-22-9 | Trace Elements: Cobalt (II) nitrate hexahydrate |
Compressor | Makita | MAC700 | This equipment is used for the injection CO2 system |
Control Valve | Sierra Instruments | SmartTrak 100 | This item needs to be customized for your application. In our case, it was used a 5% CO2 and 95% air mixture. |
Copper (II) Sulfate Pentahydrate (CuSO4*5H2O) | Sigma-Aldrich | 7758-99-8 | Trace Elements: Copper (II) Sulfate Pentahydrate |
Data Logger: Campbell unit CR3000 | Scientific Campbell | CR3000 | This equipment is used for controlling all the system, motoring and recording data |
Dissolvde Oxygen Solution | Campbell Scientific | 14055 | Dissolved oxygen electrolyte solution DO6002 – Lot No. 211085 |
Dissolved Oxygen probe | Sensorex | | DO6400/T Dissolved Oxygen Sensor with Digital Communication |
Electroconductivity calibration solution | Ricca Chemical Company | 2245 – 32 ( R2245000-1A ) | Conductivity Standard, 5000 uS/cm at 25C (2620 ppm TDS as NaCl) |
Electroconductivity probe sensor | Hanna Instruments | HI3003/D | Flow-thru Conductivity Probe – NTC Sensor, DIN Connector, 3m Cable |
Ethylenediaminetetraacetic acid disodium salt dihydrate (Na2EDTA*2H2O) | Sigma-Aldrich | 6381-92-6 | Medium Preparation: Ethylenediaminetetraacetic acid disodium salt dihydrate |
Filters | Fisher Scientific | 09-874-48 | Whatman Binder-Free Glass Microfiber Filters |
Flasks | Fisher scientific | 09-552-40 | Pyrex Fernbach Flasks |
Furnace | Hogentogler | Model: F6020C-80 | Thermo Sicentific Thermolyne F6020C – 80 Muffle Furnace |
Glass dessicator | VWR International LLC | 75871-430 | Type 150, 140 mm of diameter |
Glass funnel | Fisher Scientific | FB6005865 | Fisherbrand Reusable Glass Long-Stem Funnels |
Laminar flow hood | Fisher Hamilton Safeair | Fisher Hamilton Stainless Safeair hume hood | |
Magnesium sulfate heptahydrate (MgSO4*7H2O) | Fisher Scientific | 10034 – 99 – 8 | Medium Preparation: Magnesium sulfate heptahydrate |
Methanol | Sigma-Aldrich | 67-56-1 | Lipid extraction solvent |
Micro bubble Diffuser | Pentair Aquatic Eco-Systems | 1PMBD075 | This equipment is used for the injection CO2 system |
Microalgae: Chlorella Sorokiniana | NAABB | DOE 1412 | |
Microoscope | Carl Zeiss 4291097 | ||
Microwave assistant extraction | MARS, CEM Corportation | CEM Mars 5 Xtraction 230/60 Microwave Accelerated Reaction System. Model: 907601 | |
MnCl2*4H2O | Sigma-Aldrich | 13446-34-9 | Manganese(II) chloride tetrahydrate |
Mortars | Fisher Scientific | FB961B | Fisherbrand porcelein mortars |
Nitrogen evaporator | Organomation | N-EVAP 112 Nitrogen Evaporatpr (OA-SYS Heating System) | |
Oven | VWR International LLC | 89511-410 | Forced Air Oven |
Paddle Wheel | 8-blade horizontal axis propeller. This usually comes as part of the paddlewheel reactor. | ||
Paddle wheel motor | Leeson | M1135042.00 | Leeson, Model: CM34025Nz10C; 1/4 HP; Volts 90; FR 34; 62 RPM. |
Pestles | Fisher Scientific | FB961M | Fisherbrand porcelein pestles |
pH and EC Transmitter | Hanna Instruments | HI98143 | Hanna Instruments HI98143-04 pH and EC Transmitter with Galvanic isolated 0-4V. |
pH calibration solutions | Fisher Scientific | 13-643-003 | Thermo Scientific Orion pH Buffer Bottles |
pH probe sensor | Hanna Instruments | HI1006-2005 | Hanna Instruments HI1006-2005 Teflon pH Electrode with matching pin 5m. |
Pippete tips | Fisher Scientific | 1111-2821 | 1000 ul TipOne graduated blue tip in racks |
Pippetter | Fisher Scientific | 13-690-032 | Eppendorf Reserch plus Variable Adjustable Volume Pipettes: Single-channel |
Plastic cuvettes | Fisher scientific | 14377017 | BrandTech BRAND Plastic Cuvettes |
Plates | Fisher scientific | 08-757-100D | Corning Falcon Bacteriological Petri Dishes with Lid |
Potash | This chemical is used for the optimazed medium preparation. It was bought in a fertilizer local company | ||
Potassium phosphate dibasic (K2HPO4) | Sigma-Aldrich | 7758 -11 – 4 | Medium Preparation: Potassium phosphate dibasic |
Pyrex reusable Media Storage Bottles | Fisher scientific | 06-414-2A | 1 L and 2 L bottels – PYREX GL45 Screw Caps with Plug Seals |
Raceway Pond | Similar equipment can be bought at https://microbioengineering.com/products | ||
Real Time Optical Density Sensor | University of Arizona | This equipment was design and build by a member of the group | |
RS232 Cable | Sabrent | Sabrent USB 2.0 to Serial (9-Pin) DB-9 RS-232 Converter Cable, Prolific Chipset, Hexnuts, [Windows 10/8.1/8/7/VISTA/XP, Mac OS X 10.6 and Above] 2.5 Feet (CB-DB9P) | |
Shaker Table | Algae agitation 150 rpm | ||
Sodium Carbonate (Na2CO3) | Sigma-Aldrich | 497-19-8 | Sodium carbonate |
Sodium molybdate dihydrate (Na2MoO4*2H2O) | Sigma-Aldrich | 10102-40-6 | Medium Preparation: Sodium molybdate dihydrate |
Sodium nitrate (NaNO3) | Sigma-Aldrich | 7631-99-4 | Medium Preparation: Sodium nitrate |
Spectophotometer | Fisher Scientific Company | 14-385-400 | Thermo Fisher Scientific – 10S UV-Vis GENESTYS Spectrophotometer cylindrical Longpath cell holder; internal reference dectector, Xenon flash lamp; dual silicon photodiode; 240V, 50 to 60Hz selected automatically. |
Test tubes | Fisher Scientific | 14-961-27 | Fisherbrand Disposable Borosilicate Glass Tubes with Plain End (10 ml) |
Thermocouples type K | Omega | KMQXL-125G-6 | |
Urea | Sigma-Aldrich | 2067-80-3 | Urea |
Vacuum filtration system | Fisher Scientific | XX1514700 | MilliporeSigma Glass Vacuum Filter Holder, 47 mm. The system includes: Ground glass flask attachment, coarse-frit glass filter support, and flask |
Vacuum pump | Grainger | Marathon Electric AC Motor Thermally protected G588DX – MOD 5KH36KNA510X. HP 1/4. RPM 1725/1425 | |
Zinc sulfate heptahydrate (ZnSO4*7H2O) | Sigma-Aldrich | 7446-20-0 | Zinc sulfate heptahydrate |