scholarly journals Biomass accumulation-influencing factors in microalgae farms

2020 ◽  
Vol 24 (2) ◽  
pp. 134-139
Author(s):  
Gerson O. L. Pedruzi ◽  
Matheus L. Amorim ◽  
Raquel R. Santos ◽  
Márcio A. Martins ◽  
Marcelo G. M. V. Vaz
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Influencing Factors ◽  
Biomass Accumulation ◽  
Gas Diffusion ◽  
Flue Gases ◽  
Nitrogen And Phosphorus ◽  
Nutrient Distribution ◽  
Diffusion Of Gases

ABSTRACT Due to the emergence of large microalgae farms and increased competition in this sector, the search for higher productivity is common. One way to achieve this goal in microalgae production is to optimize the factors that influence their growth during the cultivation stage to increase the accumulation of bio-compounds of interest. In this stage, the factors that most influence are: nutrition, gas diffusion, light intensity and quality and, finally, stirring, which directly affects all other factors. Thus, a review and an evaluation of the influence and importance of stirring were performed in the present study. The nutrients that most influence biomass accumulation are carbon, nitrogen and phosphorus, but their proportion is directly related to the proposed objective for microalgae. In the diffusion of gases, it is essential to supply adequate CO2 for the growth of microalgae, and flue gases can be used. Also, it is necessary to ensure proper removal of photosynthetic O2, which could inhibit microalgae metabolism and slow their growth rate. It is important to provide the appropriate light intensity for photosynthesis, but excess may cause photoinhibition in cultivation. Stirring is of paramount importance to ensure nutrient distribution in the medium, gas diffusion (incorporation of CO2 and removal of O2) and adequate exposure of microalgae to light, reducing the effects of photoinhibition and self-shading.

STUDY OF GROWTH AND N, P CONTENT OF MICROALGAE Chlorella vulgaris CULTIVATED IN DIFFERENT CULTURE MEDIA AND LIGHT INTENSITY

2016 ◽  
Vol 78 (4-2) ◽  
Author(s):  
Dedi Edwin Satriaji ◽  
Muhammad Zainuri ◽  
Ita Widowati
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Specific Growth Rate ◽  
Chlorella Vulgaris ◽  
Specific Growth ◽  
Culture Media ◽  
Algal Growth ◽  
Nitrogen And Phosphorus ◽  
Cell Content ◽  
Media Type

Different light intensity and different media types were used to test their effects on algal growth and biochemical composition of cell content to optimize the growth of algal biomass production. Analysis of the results includes growth calculation of Chlorella vulgaris obtained from 6 d observations for 12 h a day (06:00 am to 06:00 pm) with 3 h breaks in between observation. Laboratory analysis was done at the end of day 5th to determine the content of N, and P. Density of C. vulgaris were influenced by both light intensity and media. Differences media type and light intensity as separated parameters and their interactions significantly (p < 0.05) affected on the growth and nitrogen and phosphor content of C. vulgaris. The highest density of  2 310 × 104 cells · mL–1 was on day 4 with walne media resulting in specific growth rate (µ) of 0.43 per day with a  light intensity of 5 000 lux, and the lowest density of 725 × 104 cells · mL–1 was in day 4 with the NPK media and specific growth rate (µ) 0.25 per day with a light intensity of 4 000 lux. The highest nitrogen and phosphorus content (16.12 mg and 28.19 mg) was obtained from walne medium with a light intensity of 5000 lux, and the lowest (3.43 mg and 2.17 mg) was obtained from NPK with a light intensity of 4 000 lux.

scholarly journals Biological scaling in green algae: the role of cell size and geometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helena Bestová ◽  
Jules Segrestin ◽  
Klaus von Schwartzenberg ◽  
Pavel Škaloud ◽  
Thomas Lenormand ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Internal Diffusion ◽  
Scaling Exponent ◽  
Power Scaling ◽  
Nutrient Distribution ◽  
Metabolic Scaling ◽  
Key Factor ◽  
Size And Morphology

AbstractThe Metabolic Scaling Theory (MST), hypothesizes limitations of resource-transport networks in organisms and predicts their optimization into fractal-like structures. As a result, the relationship between population growth rate and body size should follow a cross-species universal quarter-power scaling. However, the universality of metabolic scaling has been challenged, particularly across transitions from bacteria to protists to multicellulars. The population growth rate of unicellulars should be constrained by external diffusion, ruling nutrient uptake, and internal diffusion, operating nutrient distribution. Both constraints intensify with increasing size possibly leading to shifting in the scaling exponent. We focused on unicellular algae Micrasterias. Large size and fractal-like morphology make this species a transitional group between unicellular and multicellular organisms in the evolution of allometry. We tested MST predictions using measurements of growth rate, size, and morphology-related traits. We showed that growth scaling of Micrasterias follows MST predictions, reflecting constraints by internal diffusion transport. Cell fractality and density decrease led to a proportional increase in surface area with body mass relaxing external constraints. Complex allometric optimization enables to maintain quarter-power scaling of population growth rate even with a large unicellular plan. Overall, our findings support fractality as a key factor in the evolution of biological scaling.

scholarly journals Effect of Light Intensity and Quality on Growth Rate and Composition of Chlorella vulgaris

Plants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 31 ◽  
Author(s):  
Maria N. Metsoviti ◽  
George Papapolymerou ◽  
Ioannis T. Karapanagiotidis ◽  
Nikolaos Katsoulas
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Chlorella Vulgaris ◽  
Lipid Content ◽  
Growth Rates ◽  
Solar Irradiance ◽  
White Led ◽  
Microalgal Biomass ◽  
Nm Range ◽  
Effect Of Light

In this research, the effect of solar irradiance on Chlorella vulgaris cultivated in open bioreactors under greenhouse conditions was investigated, as well as of ratio of light intensity in the 420–520 nm range to light in the 580–680 nm range (I420–520/I580–680) and of artificial irradiation provided by red and white LED lamps in a closed flat plate laboratory bioreactor on the growth rate and composition. The increase in solar irradiance led to faster growth rates (μexp) of C. vulgaris under both environmental conditions studied in the greenhouse (in June up to 0.33 d−1 and in September up to 0.29 d−1) and higher lipid content in microalgal biomass (in June up to 25.6% and in September up to 24.7%). In the experiments conducted in the closed bioreactor, as the ratio I420–520/I580–680 increased, the specific growth rate and the biomass, protein and lipid productivities increased as well. Additionally, the increase in light intensity with red and white LED lamps resulted in faster growth rates (the μexp increased up to 0.36 d−1) and higher lipid content (up to 22.2%), while the protein, fiber, ash and moisture content remained relatively constant. Overall, the trend in biomass, lipid, and protein productivities as a function of light intensity was similar in the two systems (greenhouse and bioreactor).

scholarly journals Effects of light intensity and temperature on Cylindrospermopsis raciborskii (Cyanobacteria) with straight and coiled trichomes: growth rate and morphology

2012 ◽  
Vol 72 (2) ◽  
pp. 343-351 ◽  
Author(s):  
MC. Bittencourt-Oliveira ◽  
B. Buch ◽  
TC. Hereman ◽  
JDT. Arruda-Neto ◽  
AN. Moura ◽  
...  
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Morphological Changes ◽  
Population Control ◽  
Distinct Species ◽  
Cylindrospermopsis Raciborskii ◽  
Climatic Chamber ◽  
Light Intensities ◽  
Different Temperatures ◽  
Lower Temperature

Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju (Ordem Nostocales) is one of the most troublesome bloom-forming species in Brazil. Understanding the population dynamics of the different morphotypes of C. raciborskii (straight and coiled) could assist in the prediction of favourable conditions for the proliferation of this potentially toxin-producing species. The aim of the present study was to assess the effects of two different light intensities and temperatures on the growth rate and morphology of the trichomes of the straight and coiled morphotypes. For such, two non-toxin producing strains of C. raciborskii were used - one with a coiled trichome (ITEP31) and another with a straight trichome (ITEP28). The strains were cultured in BG-11 medium in a climatic chamber under controlled conditions. Two light intensities (30 and 90 µmol.m-2.s-1 ) were combined at temperatures of 21 and 31 °C and the growth rate and morphological changes were analysed. The morphotypes responded differently to the different temperatures and light intensities. Both strains exhibited faster growth velocities when submitted to higher light intensity and temperature. The lower temperature and higher luminosity hampered the development of both strains. Variations in cellular morphology and an absence of akinetes in both strains were related to the lower temperature (21 °C). The coiled morphotype demonstrated considerable phenotype plasticity, changing the morphology of trichome throughout its growth curve. Although molecular analysis does not sustain the separation of the morphotypes as distinct species, their different eco-physiological responses should be considered further knowledge of extreme importance for the population control of these potentially toxic organisms.

scholarly journals Effects of Photosynthetic Activity Radiation (PAR) on Green Mustard Plant Growth (Brassica rapa var. parachinensis L.)

2019 ◽  
Vol 20 (1) ◽  
pp. 19
Author(s):  
Ni Nyoman Ratini ◽  
I Wayan Supardi ◽  
Yuli Nurfadhillah
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Plant Height ◽  
Photosynthetic Activity ◽  
Plant Biomass ◽  
Vegetative Phase ◽  
Active Radiation ◽  
Blue Filter ◽  
Mustard Plant ◽  
Number Of Leaves

A research on the effect of photosynthetic active radiation (PAR) on the growth of green mustard plants has been conducted. The radiation source used is sunlight. Samples have been grouped as a sample which treated by red filter (P1), by orange filter (P2), by purple filter (P3), by green filter (P4), by blue filter (P5) and a sample without filter as a control (P0). Each sample consisted of four plants. The planting was carried out using polybags with compost media. Observations were made from the nursery phase to the slow vegetative phase (day 3rd, when all plants had grown shoots until day 63rd of the harvest). Parameters measured include light intensity, plant height and number of leaves. Measurement is done every three days. Also it measured plant biomass on the last day of observation (63rd day). The results showed that the intensity of each sample had an impact on the harvest. The best growth rate is obtained in P2, both in the nursery phase and fast vegetative phase i.e. 0.119 cm/day and 0.194 cm/day, respectively. While the highest growth rate was obtained in the P3 sample, namely the slow vegetative phase (0.035 cm/day). Overall the best planting results were obtained in P2 samples with plant height of 23.18 cm, number of leaves of 12 strands and plant biomass of 33.56 g.

Modelling microbial growth and biomass accumulation during methane oxidation in unsaturated soil

2020 ◽  
Vol 57 (2) ◽  
pp. 189-204
Author(s):  
Song Feng ◽  
Anthony Kwan Leung ◽  
Hong Wei Liu ◽  
Charles Wang Wai Ng ◽  
Wan Peng Tan
Keyword(s):  
Methane Oxidation ◽  
Unsaturated Soil ◽  
Reactive Transport ◽  
Microbial Growth ◽  
Gas Permeability ◽  
Biomass Accumulation ◽  
Gas Diffusion ◽  
Class B ◽  
Water Gas ◽  
Soil Pores

Microbial aerobic methane oxidation (MAMO) affects methane emissions through landfill covers by not only consuming methane, but also causing biomass accumulation associated with bacterial growth. Although the reduction of soil porosity by biomass accumulation has been well recognized, most existing models ignore this effect when estimating MAMO efficiency. The present study proposes a newly improved theoretical model that could consider the effects of both microbial growth and biomass accumulation on MAMO during coupled water–gas–heat reactive transport in unsaturated soil. Comprehensive batch incubation tests were performed to determine the input parameters required. Part of a set of published experimental data was used to validate the new model, while the remainder of the dataset was used to evaluate the model predictability of soil–microbe interaction (i.e., class B prediction). When ambient temperature is relatively high (30 °C), ignoring biomass accumulation would lead to an overestimation of MAMO efficiency by more than three times. As the biomass accumulated in soil pores, the water permeability, gas permeability, and gas diffusion in the unsaturated soil reduced, consequently limiting the supply of oxygen to the bacteria for MAMO to take place.

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