scholarly journals PHAEODACTYLUM TRICORNUTUM MICROALGAE GROWTH RATE IN HETEROTROPHIC AND MIXOTROPHIC CONDITIONS

2009 ◽  
Vol 8 (1) ◽  
pp. 84 ◽  
Author(s):  
K. C. C. Morais ◽  
R. L. L. Ribeiro ◽  
K. R. Santos ◽  
D. M. Taher ◽  
A. B. Mariano ◽  
...  
Keyword(s):  
Growth Rate ◽  
Phaeodactylum Tricornutum ◽  
Agricultural Land ◽  
Production Costs ◽  
Biofuel Production ◽  
Glycerol Concentration ◽  
Microalgae Biomass ◽  
Dry Biomass ◽  
Number Of Cells ◽  
Microalgae Growth

The Brazilian National Program for Biofuel Production has been encouraging diversification of feedstock for biofuel production. One of the most promising alternatives is the use of microalgae biomass for biofuel production. The cultivation of microalgae is conducted in aquatic systems, therefore microalgae oil production does not compete with agricultural land. Microalgae have greater photosynthetic efficiency than higher plants and are efficient fixing CO2. The challenge is to reduce production costs, which can be minimized by increasing productivity and oil biomass. Aiming to increase the production of microalgae biomass, mixotrophic cultivation, with the addition of glycerol has been shown to be very promising. During the production of biodiesel from microalgae there is availability of glycerol as a side product of the transesterification reaction, which could be used as organic carbon source for microalgae mixotrophic growth, resulting in increased biomass productivity. In this paper, to study the effect of glycerol in experimental conditions, the batch culture of the diatom Phaeodactylum tricornutum was performed in a 2-liter flask in a temperature and light intensity controlled room. During 16 days of cultivation, the number of cells per ml was counted periodically in a Neubauer chamber. The calculation of dry biomass in the control experiment (without glycerol) was performed every two days by vacuum filtration. In the dry biomass mixotrophic experiment with glycerol concentration of 1.5 M, the number of cells was assessed similarly in the 10th and 14th days of cultivation. Through a volume element methodology, a mathematical model was written to calculate the microalgae growth rate. Was used an equation that describes the influence of irradiation and concentration of nutrients in the growth of microalgae. A simulation time of 16 days was used in the computations, with initial concentration of 0.1 g l-1. In order to compare simulation data with experimental data, we calculated the dry weight in 8 points in the course of sixteen days. In this way, it was possible to assess graphically biomass concentration versus time through the experiments and by numerical simulation. It was identified that the simulation results were consistent with the experiments and that the addition of glycerol greatly influenced the growth of microalgae. In the present analysis, the glycerol added increased 30% in biomass.

scholarly journals Inexpensive and universal growth media for biomass production of microalgae

2019 ◽  
Vol 21 (1) ◽  
pp. 82-89 ◽  
Keyword(s):  
Chlorella Vulgaris ◽  
Algal Biomass ◽  
Large Scale ◽  
Sea Water ◽  
Production Costs ◽  
Growth Media ◽  
Growing Medium ◽  
Microalgae Biomass ◽  
Mixotrophic Conditions ◽  
Microalgae Growth

<p>New challenges for industrial microbiology and biotechnology of algae are to increase the efficiency of microalgae growth rates and decrease the cultivation costs. Algae could be cultivated in fresh water as well as in salty sea water or wastewater. Microalgae biomass can be used as a sorbent to remove microcontaminants (e.g. heavy metals, biogens) from wastewater. The obtained results showed that there is a possibility of application of a cheap and universal growing medium (Bf) despite common fertilizers: Bristol or BG-11 to cultivate Chlorella vulgaris and Scenedesmus armatus. The mixotrophic condition can be useful for cultivation of Chlorella vulgaris and Scenedesmus armatus. The highest concentrations of algal biomass for both species were determined after the application of the Bf medium, lower after the BG-11 medium and the lowest after the Br medium in autotrophic as well as mixotrophic conditions. The number of C. vulgaris cells in mixotrophic conditions was higher than S. armatus. The utilization of cheap growing media will lowering the production costs of algal biomass on a large scale.</p>

scholarly journals On the theoretical prediction of microalgae growth for parallel flow

2020 ◽  
Author(s):  
Chunyang Ma
Keyword(s):  
Growth Rate ◽  
Growth Models ◽  
Concentration Field ◽  
Parallel Flow ◽  
Biofuel Production ◽  
Order Of Magnitude ◽  
Growth Problem ◽  
Semi Empirical ◽  
First Time ◽  
Microalgae Growth

Abstract Background: The established microalgae growth models are semi-empirical or considerable fitting coefficients exist. Therefore, the ability of the model prediction is reduced by the numerous fitting coefficients. Furthermore, the predicted results of the established models are dependent on the size of the photobioreactor (PBR), light intensity, flow and concentration field. The growth mechanism of microalgae has not clearly understood in PBR cultivation. It is difficult to predict the microalgae growth by theoretical methods, owing to the aforementioned factors. We developed an exploratory bridging microalgae growth model to predict the microalgae growth rate in PBRs by using the nondimensional method which is effectively in fluid dynamics and heat transfer. Results: The analytical solution of the growth rate was obtained for the parallel flow. The nondimensional growth rate expressed as function of Reynolds number and Schmidt number, which can be used for arbitrary parallel flow due to the solution was expressed as nondimensional quantities. The theoretically predicted growth rate is compared with the experimentally measured microalgae growth rate on the order of magnitude. Conclusions: The nondimensional method successfully applied to the microalgae growth problem for the first time. The general nondimensional solution can unify the numerous experimental data for different laboratory conditions, and give a direction for the disorder of the microalgae growth problem. The nondimensional solution will be useful in the design and operation of PBRs for biofuel production.

scholarly journals On the theoretical prediction of microalgae growth for parallel flow

2020 ◽  
Author(s):  
Chunyang Ma
Keyword(s):  
Growth Rate ◽  
Growth Models ◽  
Concentration Field ◽  
Parallel Flow ◽  
Biofuel Production ◽  
Order Of Magnitude ◽  
Growth Problem ◽  
Semi Empirical ◽  
First Time ◽  
Microalgae Growth

Abstract Background: The established microalgae growth models are semi-empirical or considerable fitting coefficients exist. Therefore, the ability of the model prediction is reduced by the numerous fitting coefficients. Furthermore, the predicted results of the established models are dependent on the size of the photobioreactor (PBR), light intensity, flow and concentration field. The growth mechanism of microalgae has not clearly understood in PBR cultivation. It is difficult to predict the microalgae growth by theoretical methods, owing to the aforementioned factors. We developed an exploratory bridging microalgae growth model to predict the microalgae growth rate in PBRs by using the nondimensional method which is effectively in fluid dynamics and heat transfer.Results: The analytical solution of the growth rate was obtained for the parallel flow. The nondimensional growth rate expressed as function of Reynolds number and Schmidt number, which can be used for arbitrary parallel flow due to the solution was expressed as nondimensional quantities. The theoretically predicted growth rate is compared with the experimentally measured microalgae growth rate on the order of magnitude.Conclusions: The nondimensional method successfully applied to the microalgae growth problem for the first time. The general nondimensional solution can unify the numerous experimental data for different laboratory conditions, and give a direction for the disorder of the microalgae growth problem. The nondimensional solution will be useful in the design and operation of PBRs for biofuel production.

scholarly journals Influence of Carbohydrate Additives on the Growth Rate of Microalgae Biomass with an Increased Carbohydrate Content

Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 381
Author(s):  
Anna Andreeva ◽  
Ekaterina Budenkova ◽  
Olga Babich ◽  
Stanislav Sukhikh ◽  
Vyacheslav Dolganyuk ◽  
...  
Keyword(s):  
Growth Rate ◽  
Chlorella Vulgaris ◽  
Nutrient Medium ◽  
Dunaliella Salina ◽  
Arthrospira Platensis ◽  
Carbohydrate Content ◽  
Biofuel Production ◽  
Total Carbohydrate ◽  
Microalgae Biomass ◽  
Total Carbohydrates

Our study focused on investigating the possibilities of controlling the accumulation of carbohydrates in certain microalgae species (Arthrospira platensis Gomont, Chlorella vulgaris Beijer, and Dunaliella salina Teod) to determine their potential in biofuel production (biohydrogen). It was found that after the introduction of carbohydrates (0.05 g⋅L−1) into the nutrient medium, the growth rate of the microalgae biomass increased, and the accumulation of carbohydrates reached 41.1%, 47.9%, and 31.7% for Arthrospira platensis, Chlorella vulgaris, and Dunaliella salina, respectively. Chlorella vulgaris had the highest total carbohydrate content (a mixture of glucose, fructose, sucrose, and maltose, 16.97%) among the studied microalgae, while for Arthrospira platensis and Dunaliella salina, the accumulation of total carbohydrates was 9.59% and 8.68%, respectively. Thus, the introduction of carbohydrates into the nutrient medium can stimulate their accumulation in the microalgae biomass, an application of biofuel production (biohydrogen).

scholarly journals Controlling of two destructive zooplanktonic predators in Chlorella mass culture with surfactants

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xiaobin Wen ◽  
Aoqi Zhang ◽  
Xiaoyan Zhu ◽  
Lin Liang ◽  
Yan Huo ◽  
...  
Keyword(s):  
Mass Culture ◽  
Chemical Method ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Biofuel Production ◽  
Benzene Sulfonate ◽  
Microalgae Biomass ◽  
Mass Cultures ◽  
Dodecyl Benzene Sulfonate ◽  
Raceway Ponds

Abstract Background Predatory flagellates and ciliates are two common bio-contaminants which frequently cause biomass losses in Chlorella mass culture. Efficient and targeted ways are required to control these contaminations in Chlorella mass cultivation aiming for biofuel production especially. Results Five surfactants were tested for its ability to control bio-contaminations in Chlorella culture. All five surfactants were able to eliminate the contaminants at a proper concentration. Particularly the minimal effective concentrations of sodium dodecyl benzene sulfonate (SDBS) to completely eliminate Poterioochromonas sp. and Hemiurosomoida sp. were 8 and 10 mg L−1, respectively, yet the photosynthesis and viability of Chlorella was not significantly affected. These results were further validated in Chlorella mass cultures in 5, 20, and 200 m2 raceway ponds. Conclusions A chemical method using 10 mg L−1 SDBS as pesticide to control predatory flagellate or ciliate contamination in Chlorella mass culture was proposed. The method helps for a sustained microalgae biomass production and utilization, especially for biofuel production.

Enhancement of Hydrocarbon Productivity of Botryococcus braunii by an Adenine Type Phytohormone

2012 ◽  
Vol 512-515 ◽  
pp. 397-400
Author(s):  
Jun Zhi Liu ◽  
Ya Ming Ge ◽  
Guang Ming Tian
Keyword(s):  
Growth Rate ◽  
Low Dose ◽  
Algal Growth ◽  
Botryococcus Braunii ◽  
Biofuel Production ◽  
Carotenoid Content ◽  
Algae Biofuels ◽  
Hydrocarbon Content ◽  
Algal Growth Rate ◽  
Hydrocarbon Productivity

This study examined the effects of an adenine-type cytokinin 6-benzylaminopurine (6-BA) on the growth and metabolism characteristics of Botryococcus braunii, one of the most promising oil-rich algae for biofuel production. The results showed that 6-BA of low dose (0.1-1.0 mg L-1) would enhance the algal growth rate and biochemical synthesis, whereas too much (5.0 mg L-1) would be lethally toxic for B. braunii. Noticingly, though the maximum algal growth rate, chlorophyll and β-carotenoid content were observed in the treatment with 0.5 and/or 1.0 mg L-1 6-BA, both the maximum algal hydrocarbon content and the highest hydrocarbon productivity were observed in the treatment with 0.1 mg L-1 6-BA, which were respectively 2.45 and 3.48 times of the control (39.1% vs. 16.0%, 546 mg L-1 vs. 157 mg L-1). This finding has great implications for improving algae biofuels production by phytohormone.

scholarly journals Influence of the specific growth rate on formation of sterols in yeast Saccharomyces cerevisiae during fed-batch cultivation

2000 ◽  
Vol 18 (No. 3) ◽  
pp. 110-114
Author(s):  
J. Čermák ◽  
M. Rychtera ◽  
P. Nechvíle ◽  
J. Náhlík ◽  
K. Melzoch ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Control Strategy ◽  
Respiratory Quotient ◽  
Specific Growth ◽  
Carbon Dioxide Concentration ◽  
Sterol Fraction ◽  
Yeast Cells ◽  
Dry Biomass

Ergosterol is a major sterol in yeast cells. Intermediates of ergosterol biosynthesis or products of ergosterol biotransformation occur in cells too. Sterols mainly form components of cell membranes. Fluidity of membranes is affected by sterols. The amount of sterols in cells can be influenced above all by cultivation conditions and by the yeast genotype. Specific growth rate is an important factor which affects the amount of sterols present in yeast cells. We carried out a series of 24-hour cultivations to find out the impact of specific growth rate on sterol biosynthesis. Inflow of synthetic medium to the bioreactor was controlled by means of a profile of carbon dioxide concentration in the outlet gases. This profile was acquired by simulation according to a mathematical model of cultivation. Profile of carbon dioxide concentration corresponded to a precalculated profile of specific growth rate. Cultivation was divided into two phases with different growth rate values. A constant value of the specific growth rate was maintained in the 1st phase. The specific growth rate value decreased by controlling the inflow in the 2nd phase (beginning at 12th hour of cultivation). Other cultivations were carried out using so-called physiological control which consisted in determining the immediate physiological state (e.g., RQ) and the choice of control strategy according to the metabolic state. Selected control strategy ensures an immediate action (inflow of the medium). If the specific growth rate decreased in the 1st phase, the amount of total sterols in yeast dry biomass increased (to 2.7% in yeast dry biomass). But the purity of ergosterol decreased (amount of sterol contaminants increased up to 23.3% in the sterol fraction). If a constant value of respiratory quotient was maintained (at about 1.1), the amount of total sterols in yeast dry biomass and the purity of ergosterol were constant. If the value of respiratory quotient was changed in the growth and final phase of cultivation, the amount of total sterols in yeast dry biomass increased (to 2.83% in yeast dry biomass). However, the purity of ergosterol decreased (amount of sterol contaminants increased up to 21.2% in sterol fraction).

scholarly journals Identifying new criteria for assessing the impact on the ecosystem generated by the establishment of Jerusalem artichoke crops on difficult and floodable soils

2021 ◽  
Vol 286 ◽  
pp. 03022
Author(s):  
Florin Nenciu ◽  
Gabriel Nae ◽  
Gabriela Milian ◽  
Iulian Dumitru ◽  
Gheorghe Matei ◽  
...  
Keyword(s):  
Agricultural Land ◽  
Jerusalem Artichoke ◽  
Raw Material ◽  
Biofuel Production ◽  
Land Owners ◽  
Marginal Soils ◽  
Pharmaceutical Industries ◽  
The Impact ◽  
Near Future ◽  
Technical Plant

Jerusalem Artichoke (Helianthus tuberosus L.) is a technical plant that manages to adapt very well to unfriendly environments, even in polluted or poor in nutrients soils and may serve in the near future as an important raw material for the food, chemical, and pharmaceutical industries. Furthermore, the plant is growing rapidly, producing large amounts of biomass and offers the possibility to be harvested up to 2 times a year, therefore presents a high potential to be used in the field of biofuel production. The plant's capacity to multiply easily by developing small tubers in the soil, allowing the production of economically advantageous crops, can be considered an advantage for biofuel producers, however this feature might be a drawback for agricultural land owners considering the very invasive behavior. The present paper aim to assess two Jerusalem Artichokes crops established on marginal soils, assessing productivity and the extensive impact on the ecosystem, paying a special attention to plant invasiveness tendencies.

Global trends in population, energy use and climate: implications for policy development, rangeland management and rangeland users

2013 ◽  
Vol 35 (2) ◽  
pp. 117 ◽  
Author(s):  
Jerry L. Holechek
Keyword(s):  
United States ◽  
Natural Resources ◽  
Interest Rates ◽  
Fresh Water ◽  
Human Population ◽  
Agricultural Land ◽  
Land Development ◽  
The United States ◽  
Livestock Production ◽  
Production Costs

Increasing world human population, declining reserves of cheaply extracted fossil fuels, scarcity of supplies of fresh water and climatic instability will put tremendous pressure on world rangelands as the 21st century progresses. It is expected that the human population of the world will increase by 40% by 2050 but fossil fuel and reserves of fresh water will be drastically reduced. Avoiding food shortages and famine could be a major world challenge within the next 10 years. Under these conditions, major changes in policies relating to economic growth and use of natural resources seem essential. Stabilisation of the human population, development of clean and renewable energy, enhanced supplies of water and its quality, increased livestock production, and changed land-use policies, that minimise agricultural land losses to development and fragmentation, will all be needed to avoid declining living conditions at the global level. The health and productivity of rangelands will need to receive much more emphasis as they are a primary source of vital ecosystem services and products essential to human life. Changes in tax policies by developed, affluent countries, such as the United States, Australia and Canada, are needed that emphasise saving and conservation as opposed to excessive material consumption and land development. Extreme levels of debt and chronic deficits in trade by the United States and European Union countries need to be moderated to avoid a devastating collision of debt, depletion of natural resources, and environmental degradation. Over the next 10 years, livestock producers of the rangelands will benefit from a major increase in demand and prices for meat. Rapidly increasing demand for meat in China and other Asian countries is driving this trend. Rangeland managers, however, will also likely encounter greater climatic, financial, biological and political risks. Higher interest rates, higher production costs and higher annual variability in forage resources are major challenges that will confront rangeland managers in the years ahead. Under these conditions, a low risk approach to livestock production from rangelands is recommended that involves conservative stocking, use of highly adapted livestock, and application of behavioural knowledge of livestock to efficiently use forage resources.

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