scholarly journals Biomass and lipid induction strategies in microalgae for biofuel production and other applications

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Hossein Alishah Aratboni ◽  
Nahid Rafiei ◽  
Raul Garcia-Granados ◽  
Abbas Alemzadeh ◽  
José Rubén Morones-Ramírez

Abstract The use of fossil fuels has been strongly related to critical problems currently affecting society, such as: global warming, global greenhouse effects and pollution. These problems have affected the homeostasis of living organisms worldwide at an alarming rate. Due to this, it is imperative to look for alternatives to the use of fossil fuels and one of the relevant substitutes are biofuels. There are different types of biofuels (categories and generations) that have been previously explored, but recently, the use of microalgae has been strongly considered for the production of biofuels since they present a series of advantages over other biofuel production sources: (a) they don’t need arable land to grow and therefore do not compete with food crops (like biofuels produced from corn, sugar cane and other plants) and; (b) they exhibit rapid biomass production containing high oil contents, at least 15 to 20 times higher than land based oleaginous crops. Hence, these unicellular photosynthetic microorganisms have received great attention from researches to use them in the large-scale production of biofuels. However, one disadvantage of using microalgae is the high economic cost due to the low-yields of lipid content in the microalgae biomass. Thus, development of different methods to enhance microalgae biomass, as well as lipid content in the microalgae cells, would lead to the development of a sustainable low-cost process to produce biofuels. Within the last 10 years, many studies have reported different methods and strategies to induce lipid production to obtain higher lipid accumulation in the biomass of microalgae cells; however, there is not a comprehensive review in the literature that highlights, compares and discusses these strategies. Here, we review these strategies which include modulating light intensity in cultures, controlling and varying CO2 levels and temperature, inducing nutrient starvation in the culture, the implementation of stress by incorporating heavy metal or inducing a high salinity condition, and the use of metabolic and genetic engineering techniques coupled with nanotechnology.

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 463 ◽  
Author(s):  
Ali Nawaz Kumbhar ◽  
Meilin He ◽  
Abdul Razzaque Rajper ◽  
Khalil Ahmed Memon ◽  
Muhammad Rizwan ◽  
...  

The decline in fossil fuel reserves has forced researchers to seek out alternatives to fossil fuels. Microalgae are considered to be a promising feedstock for sustainable biofuel production. Previous studies have shown that urea is an important nitrogen source for cell growth and the lipid production of microalgae. The present study investigated the effect of different concentrations of urea combined with kelp waste extract on the biomass and lipid content of Chlorella sorokiniana. The results revealed that the highest cell density, 20.36 × 107 cells−1, and maximal dry biomass, 1.70 g/L, were achieved in the presence of 0.5 g/L of urea combined with 8% kelp waste extract. Similarly, the maximum chlorophyll a, b and beta carotenoid were 10.36 mg/L, 7.05, and 3.01 mg/L, respectively. The highest quantity of carbohydrate content, 290.51 µg/mL, was achieved in the presence of 0.2 g/L of urea and 8% kelp waste extract. The highest fluorescence intensity, 40.05 × 107 cells−1, and maximum total lipid content (30%) were achieved in the presence of 0.1 g/L of urea and 8% kelp waste extract. The current study suggests that the combination of urea and kelp waste extract is the best strategy to enhance the biomass and lipid content in Chlorella sorokiniana.


2021 ◽  
Vol 13 (16) ◽  
pp. 8873
Author(s):  
Minghao Chen ◽  
Yixuan Chen ◽  
Qingtao Zhang

Microalgae biofuel is expected to be an ideal alternative to fossil fuels to mitigate the effects of climate change and the energy crisis. However, the production process of microalgae biofuel is sometimes considered to be energy intensive and uneconomical, which limits its large-scale production. Several cultivation systems are used to acquire feedstock for microalgal biofuels production. The energy consumption of different cultivation systems is different, and the concentration of culture medium (microalgae cells contained in the unit volume of medium) and other properties of microalgae vary with the culture methods, which affects the energy consumption of subsequent processes. This review compared the energy consumption of different cultivation systems, including the open pond system, four types of closed photobioreactor (PBR) systems, and the hybrid cultivation system, and the energy consumption of the subsequent harvesting process. The biomass concentration and areal biomass production of every cultivation system were also analyzed. The results show that the flat-panel PBRs and the column PBRs are both preferred for large-scale biofuel production for high biomass productivity.


2020 ◽  
Vol 9 (1) ◽  
pp. 751-759 ◽  
Author(s):  
Xinxin Lian ◽  
Yuanjiang Lv ◽  
Haoliang Sun ◽  
David Hui ◽  
Guangxin Wang

AbstractAg nanoparticles/Mo–Ag alloy films with different Ag contents were prepared on polyimide by magnetron sputtering. The effects of Ag contents on the microstructure of self-grown Ag nanoparticles/Mo–Ag alloy films were investigated using XRD, FESEM, EDS and TEM. The Ag content plays an important role in the size and number of uniformly distributed Ag nanoparticles spontaneously formed on the Mo–Ag alloy film surface, and the morphology of the self-grown Ag nanoparticles has changed significantly. Additionally, it is worth noting that the Ag nanoparticles/Mo–Ag alloy films covered by a thin Ag film exhibits highly sensitive surface-enhanced Raman scattering (SERS) performance. The electric field distributions were calculated using finite-difference time-domain analysis to further prove that the SERS enhancement of the films is mainly determined by “hot spots” in the interparticle gap between Ag nanoparticles. The detection limit of the Ag film/Ag nanoparticles/Mo–Ag alloy film for Rhodamine 6G probe molecules was 5 × 10−14 mol/L. Therefore, the novel type of the Ag film/Ag nanoparticles/Mo–Ag alloy film can be used as an ideal SERS-active substrate for low-cost and large-scale production.


Author(s):  
Yuting Luo ◽  
Zhiyuan Zhang ◽  
Fengning Yang ◽  
Jiong Li ◽  
Zhibo Liu ◽  
...  

Large-scale production of green hydrogen by electrochemical water splitting is considered as a promising technology to address critical energy challenges caused by the extensive use of fossil fuels. Although nonprecious...


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1706
Author(s):  
Zacharias Viskadourakis ◽  
Argiri Drymiskianaki ◽  
Vassilis M. Papadakis ◽  
Ioanna Ioannou ◽  
Theodora Kyratsi ◽  
...  

In the current study, polymer-based composites, consisting of Acrylonitrile Butadiene Styrene (ABS) and Bismuth Antimony Telluride (BixSb2−xTe3), were produced using mechanical mixing and hot pressing. These composites were investigated regarding their electrical resistivity and Seebeck coefficient, with respect to Bi doping and BixSb2-xTe3 loading into the composite. Experimental results showed that their thermoelectric performance is comparable—or even superior, in some cases—to reported thermoelectric polymer composites that have been produced using other complex techniques. Consequently, mechanically mixed polymer-based thermoelectric materials could be an efficient method for low-cost and large-scale production of polymer composites for potential thermoelectric applications.


2006 ◽  
Vol 2006 ◽  
pp. 1-12
Author(s):  
A. Korobeinikov ◽  
P. Read ◽  
A. Parshotam ◽  
J. Lermit

It has been suggested that the large scale use of biofuel, that is, fuel derived from biological materials, especially in combination with reforestation of large areas, can lead to a low-cost reduction of atmospheric carbon dioxide levels. In this paper, a model of three markets: fuel, wood products, and land are considered with the aim of evaluating the impact of large scale biofuel production and forestry on these markets, and to estimate the cost of a policy aimed at the reduction of carbon dioxide in the atmosphere. It is shown that the costs are lower than had been previously expected.


2020 ◽  
Author(s):  
Diletta Morelli Venturi ◽  
Filippo Campana ◽  
Fabio Marmottini ◽  
Ferdinando Costantino ◽  
Luigi Vaccaro

<p>Zirconium based Metal-Organic Framework UiO-66 is to date considered one of the benchmark compound among stable MOFs and it has attracted a huge attention for its employment in many strategic applications. Large scale production of UiO-66 for industrial purposes requires the use of safe and green solvents, fulfilling the green chemistry principles and able to replace the use of <i>N,N</i>-Dimethyl-Formamide (DMF), which, despite its toxicity, is still considered the most efficient solvent for obtaining UiO-66 of high quality. Herein we report on a survey of about 40 different solvents with different polarity, boiling point and acidity, used for the laboratory scale synthesis of high quality UiO-66 crystals. The solvents were chosen according the European REACH Regulation 1907/2006 among those having low cost, low toxicity and fully biodegradable. Concerning MOF synthesis, the relevant parameters chosen for establishing the quality of the results obtained are the degree are the crystallinity, microporosity and specific surface area, yield and solvent recyclability. Taking into account also the chemical physical properties of all the solvents, a color code was assigned in order to give a final green assessment for the UiO-66 synthesis. Defectivity of the obtained products, the use of acidic modulators and the use of alternative Zr-salts have been also taken into consideration. Preliminary results lead to conclude that GVL (γ-valerolactone) is among the most promising solvents for replacing DMF in UiO-66 MOF synthesis. </p>


2021 ◽  
Vol 2115 (1) ◽  
pp. 012026
Author(s):  
Sonam Solanki ◽  
Gunendra Mahore

Abstract In the current process of producing vermicompost on a large-scale, the main challenge is to keep the worms alive. This is achieved by maintaining temperature and moisture in their living medium. It is a difficult task to maintain these parameters throughout the process. Currently, this is achieved by building infrastructure but this method requires a large initial investment and long-run maintenance. Also, these methods are limited to small-scale production. For large-scale production, a unit is developed which utilises natural airflow with water and automation. The main aim of this unit is to provide favourable conditions to worms in large-scale production with very low investment and minimum maintenance in long term. The key innovation of this research is that the technology used in the unit should be practical and easy to adopt by small farmers. For long-term maintenance of the technology lesser number of parts are used.


2020 ◽  
Author(s):  
Diletta Morelli Venturi ◽  
Filippo Campana ◽  
Fabio Marmottini ◽  
Ferdinando Costantino ◽  
Luigi Vaccaro

<p>Zirconium based Metal-Organic Framework UiO-66 is to date considered one of the benchmark compound among stable MOFs and it has attracted a huge attention for its employment in many strategic applications. Large scale production of UiO-66 for industrial purposes requires the use of safe and green solvents, fulfilling the green chemistry principles and able to replace the use of <i>N,N</i>-Dimethyl-Formamide (DMF), which, despite its toxicity, is still considered the most efficient solvent for obtaining UiO-66 of high quality. Herein we report on a survey of about 40 different solvents with different polarity, boiling point and acidity, used for the laboratory scale synthesis of high quality UiO-66 crystals. The solvents were chosen according the European REACH Regulation 1907/2006 among those having low cost, low toxicity and fully biodegradable. Concerning MOF synthesis, the relevant parameters chosen for establishing the quality of the results obtained are the degree are the crystallinity, microporosity and specific surface area, yield and solvent recyclability. Taking into account also the chemical physical properties of all the solvents, a color code was assigned in order to give a final green assessment for the UiO-66 synthesis. Defectivity of the obtained products, the use of acidic modulators and the use of alternative Zr-salts have been also taken into consideration. Preliminary results lead to conclude that GVL (γ-valerolactone) is among the most promising solvents for replacing DMF in UiO-66 MOF synthesis. </p>


2012 ◽  
Vol 2012 (1) ◽  
pp. 000604-000608
Author(s):  
Matthias Hartmann ◽  
Bertram Schmidt

The current research presents recent respective to the work development of a ceramic tubular probe for online substance concentration measurements. The aim was to develop a robust and acid-resistant sensor device, which can be easily included in existing procedural pipeline systems. To archive those goals a lot of factors had to be checked. For the substance concentration measurements a capacitive sensor effect was chosen. With this method even low substance concentrations down to one-tenth of a per cent can be indentified. For the package material zirconium oxide (tetragonal zirconia polycrystal – TZP) was used. Zirconium oxide is a technical ceramic which is wear-resistant, acid-resistant, has a low thermal conductivity, is electrically isolating and can be uses in a ceramic injection molding (CIM) process. In the phase of the sensor design process multiple geometries for the sensor effect and integration space for the evaluation electronics had to be considered. A standardized DN 10 DIN 32676 flanged joint was also added for an unproblematic connection to the pipelines. All these needed geometries had to be integrated into one ceramic element. As a result of these requirements a 3D CAD model of the sensor element was designed. The CAD-file has shown that there was only the CIM technology left to comprehend developed sensor geometry. CIM is a low cost process for large-scale production which is distinguished by high size accuracy. In the CIM process the material shrinkage, this is caused by the needed debindering and sintering steps, had to be considered. The developed ceramic tubular probe was successfully tested in multiple fluidic systems. It has left the test phase and is now ready for maturity phase.


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