Microalgae Nutrient Research Articles

The study of novelty nutrients supplementary scheme and methodology on advanced carbon sequestration of microalgae

Microalgae has great potential in carbon sequestration and production of biofuel even with a low concentrations of CO2. In this paper, an Andrews based microalgae growth kinetic model and a novel and multiple nutrient supplementary scheme that significantly extends the carbon sequestration period and enhances growth rates of microalgae are proposed. First, the correlation between nutrient concentration and microalgal growth is constructed experimentally. The advanced growth kinetic model incorporating nitrogen and phosphorus consumption is developed. Then, the optimum cultivation conditions including initial nutrients concentration, nutrients supplementary interval and daily nutrients supplementary quantities are obtained in the conical flask reactor. The findings led to a novel nutrient supplementation strategy that initiates with a 0.2BC concentration, followed by a 0.3BC addition at 100 h, with subsequent supplements every 72 h. After adopting this supplementary strategy, the microalgae growth rate is increased by 42.9 % and the carbon sequestration rate is increased by 56.2 % compared with that of the original microalgae cultivation method in one cultivation cycle. Finally, the universal microalgae nutrients supplementary model is proposed in a piecewise model. It can be concluded from the model that in the first cultivation period, microalgae needs a higher affinity for nutrients and after nutrients supplementary, the sensitivity to nutrient inhibition is reduced. The paper is significantly helpful to improve the sustainability of the microalgae growth rate and the carbon sequestration rate.

Development of microalgal dual-cultures for enhanced productivity in sewage: An experimental study

Microalgae polycultures can be shown greater productivity than those that characterize monocultures. Nonetheless, rapid and ready identification of optimal microalgae combinations for highly productive polyculture systems remains a challenge. By assessing the corresponding nitrogen and phosphorus utilization efficiencies, this study aimed to identify microalgal combinations that might improve productivity. Ten high-biomass-producing microalgal species in municipal sewage habitats were cultivated in an artificial municipal sewage. Four high-yielding microalgae, which additionally showed complementary nitrogen and phosphorus nutrient utilization preferences, were selected for a subsequent dual-culture experiment. The D41 dual-culture system comprising Pediastrum sp. and Micractinium sp., showed the highest biocrude yield, at 17.5 mg/L/d, which was 13 % and 69 % higher than those of A4 and A1, respectively. Additionally, D41 showed the highest total phosphorus removal rate from artificial sewage, which was 27 % higher than that of Pediastrum sp. monoculture (A4) and 22 % higher than that of the Micractinium sp. monoculture (A1). Therefore, this study demonstrated that, (a) biomass production and nitrogen and phosphorus utilization rates of the constructed microalgae dual-culture systems were higher than those of monocultures, (b) phosphorus was identified as the limiting nutrient for further enhancing microalgae productivity, and (c) the dual-culture system showed intermediate characteristics between those of the constituent monoculture systems, suggesting that microalgae can influence community structure. Through the development of adequate software packages that can integrate microalgae nutrient utilization preference of and microalgae community structure, future research will enable the development of more productive microalgae culture combinations.

Feasibility study of utilization of palm oil mill effluent (POME) as a source for microalgae nutrients

As palm oil productivity increases, the waste produced will increase. Every palm oil industry produces liquid waste known as palm oil mill effluent (POME). POME contains very high BOD and COD so that it can inhibit microalgae growth. Therefore, comprehensive research is needed to find pre-treatment steps to reduce the COD and BOD content in POME before it is used as a medium for the growth and development of microalgae. The experimental mixture procedure carried out POME and microalgae according to the specified ratio. Research shows that Pond IV POME waste can be used as wild microalgae to grow, thereby reducing the BOD and COD levels of POME waste. Variable modifiers were applied to the volume of POME to the ratio of microalgae volume and the amount of nutrients provided. Microalgae growth with a ratio of 1:4 resulted in a decrease in BOD and COD to 61.66 ppm and 173.33 ppm from 110.6 ppm and 496.67 ppm. On the effect of providing C nutrition (120 ppm), resulted in lower BOD and COD at 65.33 ppm and 186.67 ppm, while the effect of providing N (40 ppm) nutrition resulted in lower BOD and reached 55.41 ppm and 158.33 ppm.

Mechanistic behaviour of Chlorella vulgaris biofilm formation onto waste organic solid support used to treat palm kernel expeller in the recent Anthropocene

The capacity to maximize the proliferation of microalgal cells by means of topologically textured organic solid surfaces under various pH gave rise to the fundamental biophysical analysis of cell-surface attachment in this study. The substrate used in analysis was palm kernel expeller (PKE) in which the microalgal cells had adhered onto its surface. The findings elucidated the relevance of surface properties in terms of surface wettability and surface energy in relation to the attached microalgal growth with pH as the limiting factor. The increase in hydrophobicity of PKE-microalgae attachment was able to facilitate the formation of biofilm better. The pH 5 and pH 11 were found to be the conditions with highest and lowest microalgal growths, respectively, which were in tandem with the highest contact angle value at pH 5 and conversely for pH 11. The work of attachment (Wcs) had supported the derived model with positive values being attained for all the pH conditions, corroborating the thermodynamic feasibility. Finally, this study had unveiled the mechanism of microalgal attachment onto the surface of PKE using the aid of extracellular polymeric surfaces (EPS) from microalgae. Also, the hydrophobic nature of PKE enabled excellent attachment alongside with nutrients for microalgae to grow and from layer-by-layer (LbL) assembly. This assembly was then isolated using organosolv method by means of biphasic solvents, namely, methanol and chloroform, to induce detachment.

Experimental Study of Microalgae Cultivation Based on Ag/CoSO4 Selective Light Permeability

The efficiency of biomolecular accumulation (lipids, proteins, carbohydrates) and biomass productivity of microalgae were affected by the spectrum of light during cultivation. In this study, a bilayer plate-type photobioreactor was designed to cultivate Chlorella protothecoides with spectral selectivity by nanofluids. The Ag/CoSO₄ nanofluid was located in the layer between microalgae suspension and light resource, acting as a light-transmitting object to culture <i>Chlorella protothecoides</i>. Compared to the cultivation without spectral selectivity, the production of microalgae biomass increased by 5.76% with spectral selectivity by Ag/CoSO₄ nanofluid and increased by 17.14% with spectral selectivity by CoSO₄ solution. Besides, the behavior of the spectral selectivity of Ag/CoSO₄ nanofluid was more favorable to the accumulation of nutrients in the microalgae (29.46% lipids, 50.66% proteins, and 17.86% carbohydrates). The results revealed that the spectrum of light was in a range between 600 and 700 nm when visible light passed through Ag/CoSO₄ nanofluid, promoting the accumulation of nutrients in microalgae. This investigation provides a new idea for the cultivation of outdoor microalgae through the regulation of the spectrum.

Engineering microalgae as the next-generation food

Globally, microalgae are gaining attention due to their high nutritional value and broad application in the pharmaceutical, nutraceutical, food, cosmetics, bio-fertilizer, and biofuel industries. Microalgal-based foods have been shown a positive impact on human health by acting as antioxidants, antimicrobials, anti-inflammatory agents, and antiviral agents. Scale-up, production cost, and safety issues are the significant challenges in microalgae product commercialization. However, various techniques have been developed to overcome these challenges and to produce microalgae bio-products in a high amount and make them safe for human and animals use. Recently, multiple techniques such as metabolic and genetic engineering have emerged to overcome these limitations. The present review focused on the application of these engineering tools to improve biomass yield and nutrient quality in microalgae. However, these tools are proved to be very effective in enhancing the nutrients in microalgae. Limited success has been achieved to improve the quality at the industrial level.

Assessment of Domestic Wastewaters as Potential Growth Media for Chlorella vulgaris and Haematococcus pluvialis

Domestic wastewater contains chemical compounds that can be used as nutrients for microalgae. Removing these chemical compounds from wastewater by microalgae might help in reducing the operation cost of wastewater management while minimizing the cultivation cost for large-scale microalgae metabolite production. In this study, domestic wastewater collected from Indah Water Konsortium (IWK), Kuala Lumpur, Malaysia, was assessed as growth media for two types of microalgae, namely Chlorella vulgaris and Haematococcus pluvialis. The biomass growth and nutrient removal efficiency of total nitrogen (TN), total phosphorus (TP), and total ammonia (TAN) in different concentrations of diluted wastewater were measured. The results showed that biomass concentration (0.227 g/L), biomass productivity (0.029 g/L/day), and specific growth rate (0,284 d-1) yielded by C. vulgaris in 14 days of 80% wastewater were comparable to those microalgae grew in standard Bold’s Basal medium (BBM). Besides, C. vulgaris grew in 50% wastewater to remove TN, TP, and TAN with the highest removal efficiency (&gt;88%). For H. pluvialis, the biomass concentration in all wastewater concentrations was lower than BBM. The removal efficiencies of TN and TP were lower than 55%, but more than 80% for removal efficiency of TAN in 50% and 80% wastewater. Hence, C. vulgaris has better growth performance and nutrient removal efficiency than H. pluvialis. These findings indicated that IWK domestic wastewater could be used as growth media for microalgae, especially C. vulgaris.

Enhancement of nutritional value on zooplankton by alteration of algal media composition: A review

In aquaculture, fish larvae regularly need a balanced diet according to the timescale because such diets essential for constant growth and reproduction and can avoid malnutrition. Thus, the use of live food organisms is critical as it will first feed for fish larvae. Studies have shown that zooplankton have more excellent digestibility and are suitable as live prey species for different sizes than other live foods (e.g. rotifer and Artemia). However, zooplankton nutrition still needs to improve to meet the nutritional requirement for fish larvae. Feeding zooplankton with well-nourished microalgae is important as it affects the nutritional value of the zooplankton. Algal growth is related to micronutrients (e.g. nitrogen, phosphorus or selenium) supply in the culture medium and the availability of nutrients affects the quality of the algal. Thus, by enriching the algal diet with micronutrients from the culture media, the nutritional value of zooplankton can be improved. This review focuses on the nutritional value of zooplankton through the manipulation of algal media composition as well as wastewater. The relation between the composition of algal media and nitrogen and phosphorus limitation are also discussed. The review links the microalgae nutrient essential with manipulating algal media composition and the change of zooplankton nutrients.

Metabolic response of Botryococcus braunii to high bicarbonate dosages and other conditions: analysis of photosynthetic performance, productivity, and lipidomic profile

In this study the metabolic responses of Botryococcus braunii were analyzed upon different inorganic carbon dosages and nutrient limitation conditions in terms of lipid and biomass productivity, as well as photosynthetic performance. The nutritional schemes evaluated included different levels of sodium bicarbonate and nitrogen and phosphorus starvation, which were contrasted against standard cultures fed with CO2. Bicarbonate was found to be an advantageous carbon source since high dosages caused a significant increase in biomass and lipid productivity, in addition to an enhanced photosynthetic quantum yield and neutral lipids abundance. This contrasts to the commonly used approach of microalgae nutrient limitation, which leads to high lipid accumulation at the expense of impaired cellular growth, causing a decline in overall lipid productivity. The lipidome analysis served to hypothesize about the influence of the nutritional context on B. braunii structural and storage lipid metabolism, besides the adaptive responses exhibited by cells that underwent nutrient stress.

Biochemical and Morphological Characterization of Heterotrophic Crypthecodinium cohnii and Chlorella vulgaris Cell Walls.

Microalgae are attractive for the food and cosmetic industries because of their nutrient composition. However, the bioaccessibility and extractability of nutrients in microalgae are limited by the rigid and indigestible cell wall. The goal of this study is to explore the cell wall polysaccharides (CWPSs) composition and morphology in heterotrophic Crypthecodinium cohnii and Chlorella vulgaris biomasses during growth. Our results showed that glucose was the major component of CWPSs and exopolysaccharides in C. cohnii. C. vulgaris CWPSs have a similar sugar profile in exponential and stationary phases, essentially composed of rhamnose and galactose. C. vulgaris cell wall thickness increased from 82 nm in the exponential phase to 114 nm in the stationary phase and consisted of two main layers. C. cohnii's cell wall was 133 nm thick and composed of several membranes surrounding thecal plates. Understanding of the microalgae cell wall helps developing a more efficient and targeted biorefinery approach.

Approaches to improve utilization of Nannochloropsis oceanica in plant-based feeds for Atlantic salmon

Rigid cell walls of microalgae lower the digestibility and nutrient bioavailability in carnivorous fish. Extrusion is a thermo-mechanical process and a scalable technology that may break cell walls and improves nutrient utilization. It can be hypothesized that certain feed additives may further improve microalgae nutrient digestibility and feed utilization by fish. The aim of the current study was to investigate i) the effect of incorporation of 10% pre-extruded Nannochloropsis oceanica on nutrient digestibility, growth and feed utilization of Atlantic salmon post smolts, and ii) the ability of feed additives in improving the feed utilization. Four low fish meal feeds were formulated; a control without the microalga N. oceanica (CO), a feed containing 10% of the pre-extruded microalga (NC), and two feeds containing 10% of the pre-extruded microalga and supplemented with either 0.06% Digestarom® (ND) or 1% ZEOFeed (NZ). Fish (initial average weight of 227.3 ± 3.4 g) in 5 replicate tanks of each of the study groups were fed one of the experimental feeds for 68 days. The apparent digestibility of dry matter in the NC and NZ groups were significantly higher compared to the control group (CO). The digestibility of lipid was significantly lower, and digestibility of ash was higher in the alga-fed groups (NC, ND and NZ) compared to the control group (CO). The incorporation of 10% pre-extruded N. oceanica in plant-based commercial-like feeds did not affect the growth, feed utilization and whole body proximate composition of salmon. No effects of the feed additives were observed on growth, feed utilization and histomorphology of distal intestine of salmon, but cell proliferation (PCNA) was higher for fish fed the alga alone as well as the alga-ZEOfeed combination. There were no differences in polyunsaturated fatty acids in whole body of fish fed the different feeds. It is noteworthy that whole-body EPA + DHA levels of fish fed the algae feeds were maintained at the same levels as fish fed the control feed that contained 50% more fish meal and 10% more fish oil.

Cultivation of Chlorella pyrenoidosa as a raw material for the production of biofuels in palm oil mill effluent medium with the addition of urea and triple super phosphate

Background: The utilization of microalgae as a renewable energy is an important aspect in solving shortage of future oil reserve in 15 years. One of the renewable energy sources is microalgae biodiesel. Palm oil mill effluent (POME) is a wastewater that has a high content of organic materials. These organic materials can be used as growth nutrients for microalgae. Chlorella pyrenoidosa is one of the most potential microalgae used as a raw material for the production of biodiesel since it contains lipids (8%-35%). Methods: Chlorella pyrenoidosa was cultured on the POME medium with concentrations of 0%, 25%, 50%, 75%, and 100%v with addition of synthetic nutrients (urea: TSP) at the ratios of 2:1 ; 1:2 ; 0.5:1 in a 500 mL Erlenmeyer flask, at pH 6-8, aeration using aquarium pumps, and using LED lights (3000 lux). Results: It was revealed that at POME concentration of 25% and with addition of urea: TSP at a ratio of 2:1, the optimum specific growth rate (0.306/day) with the highest number of cells was 3.530 × 107 cells/mL and the highest lipid content was 36% of its dry weight. The removal efficiency of POME could be obtained from the removal efficiency of chemical oxygen demand (COD), total nitrogen, and orthophosphate (P-PO4 ), which was 70, 90.42, and 81.12%, respectively. Conclusion: According to the results, under appropriate culture conditions, C. pyrenoidosa can produce lipids with good use of nutrients contained in the POME medium.

Enhancement of biofuel production by microalgae using cement flue gas as substrate.

The cement industry generates a substantial amount of gaseous pollutants that cannot be treated efficiently and economically using standard techniques. Microalgae, a promising bioremediation and biodegradation agent used as feedstock for biofuel production, can be used for the biotreatment of cement flue gas. In specific, components of cement flue gas such as carbon dioxide, nitrogen, and sulfur oxides are shown to serve as nutrients for microalgae. Microalgae also have the capacity to sequestrate heavy metals present in cement kiln dust, adding further benefits. This work provides an extensive overview of multiple approaches taken in the inclusion of microalgae biofuel production in the cement sector. In addition, factors influencing the production of microalgal biomass are also described in such an integrated plant. In addition, process limitations such as the adverse impact of flue gas on medium pH, exhaust gas toxicity, and efficient delivery of carbon dioxide to media are also discussed. Finally, the article concludes by proposing the future potential for incorporating the microalgae biofuel plant into the cement sector.

A novel concept of bicarbonate-carbon utilization via an absorption-microalgae hybrid process assisted with nutrient recycling from soybean wastewater

Abstract A novel ammonia absorption-microalgae hybrid CO2 capture and conversion process was investigated in this study. Using rich ammonia solution (ammonium bicarbonate) as a nutrient source for microalgae cultivation, the challenge of energy-intensive regeneration may potentially be overcome. To provide other nutrients for microalgae apart from ammonium bicarbonate, soybean wastewater was used to replace BG-11 medium for resource recycling and could adjust the pH of cultivation solution to reduce the threat of NH3 escape and inhibition. Chlorella sp. L166 and L38 were cultivated in ammonium bicarbonate solution using 5-times and 10-times diluted soybean wastewater under two culture modes (direct and batch feeding). The experimental results indicated that microalgae growth could be promoted by using 5-times diluted soybean wastewater as a cultivation medium with a removal rate of 50–65% COD, 70–80% NH3-N and 95–100% TP from a wastewater purification perspective. In the hybrid system, the NH3 escape ratio decreased to 15.8% with a carbon conversion efficiency of over 60%, and effectively achieved carbon and nitrogen utilization with 78.8 mg/L/d of microalgae biomass.

Cell wall disruption: An effective strategy to improve the nutritive quality of microalgae in African catfish ( Clarias gariepinus )

The rigid cell walls of microalgae may hinder their utilization in fish feeds. The current experiment assessed the correlation between the accessibility of microalgae nutrients and their in vivo digestibility in African catfish. Nannochloropsis gaditana biomass was subjected to physical or mechanical treatments to weaken its cell wall; untreated—no disruption treatment (UNT), pasteurization (PAS), freezing (FRO), freeze-drying (FRD), cold pasteurization (L40) and bead milling (BEM). Six experimental diets formulated from differently treated and untreated microalgae (at 30% diet inclusion level) were tested on growth performance and apparent nutrient digestibility (ADCs) in juvenile African catfish. A basal diet (REF) containing no microalgae was used as reference diet. Results showed that biomass gain and feed conversion ratio of fish fed L40 and BEM diets increased by 13% and 11%, respectively, relative to the UNT diet. Additionally, FRD, FRO, L40 and BEM cell wall disruption treatments improved protein digestibility by 0.5%, 5.9%, 8.4% and 16.3%, respectively, compared to the UNT treatment. There was a positive correlation between accessibility of microalgal nutrients and their digestibility in African catfish. Nutrient digestibility of microalgae was dependent on extent of cell disruption. Also, the impact of cell disruption on nutrient digestibility of microalgae differs between African catfish and Nile tilapia.

Integrasi Bioremediasi Limbah Peternakan Sapi dan Kultivasi Mikroalga Chlorella vulgaris dan Chlorella pyrenoidosae

&lt;p&gt;Dairy manure that functioned as organic fertilizer has potential impact as environmental destructive waste because the absorption of inorganic nutrients in the fertilizer. On the other hand, microalgae growth is hindered by the high cost of culture, whereas organic and inorganic nutrient requirements. Dairy manure have the potential for microalgae nutrients, but are hindered by turbidity levels. Its has been tested for dilution dairy manure and treatments on fluorescence and sunlight sources and the addition of urea commercial fertilizer to absorbs organic and inorganic nutrients. Its prove the integration of bioremediation of dairy manure and microalgae cultivation Chlorella pyrenoidosa and Chlorella vulgaris can be performed and also serves as a source of caratenoid (chlorophyll)&lt;/p&gt;

Chlorella vulgaris as a Source of Essential Fatty Acids and Micronutrients: A Brief Commentary

Polyunsaturated fatty acids (PUFAs) comprise about 35-40% of the total lipid content from green algaeChlorella, reaching up to 24% linoleic acid and 27% α-linolenic acid inC. vulgaris. Also, microalgae nutrient composition may be modulated by changes in the culture medium, increasing fatty acid and microelement concentrations in the algae biomass. PUFAs, such as α-linolenic (n-3) and linoleic (n-6) acids, as well as its derivatives, are considered essential for dietary consumption, and their ability to regulate body chemistry has been recently explored in depth. A balanced fatty acid consumption is shown to counteract the negative effects of western diets, such as chronic inflammation and glucose intolerance. In this brief commentary, technological and practical uses ofC. vulgarisare explored as means to improve dietary quality and, ultimately, human health.

Combined nitrogen limitation and cadmium stress stimulate total carbohydrates, lipids, protein and amino acid accumulation in Chlorella vulgaris (Trebouxiophyceae)

Metals have interactive effects on the uptake and metabolism of nutrients in microalgae. However, the effect of trace metal toxicity on amino acid composition of Chlorella vulgaris as a function of varying nitrogen concentrations is not known. In this research, C. vulgaris was used to investigate the influence of cadmium (10−7 and 2.0×10−8molL−1 Cd) under varying nitrogen (2.9×10−6, 1.1×10−5 and 1.1×10−3molL−1N) concentrations on its growth rate, biomass and biochemical composition. Total carbohydrates, total proteins, total lipids, as well as individual amino acid proportions were determined. The combination of Cd stress and N limitation significantly inhibited growth rate and cell density of C. vulgaris. However, increasing N limitation and Cd stress stimulated higher dry weight and chlorophyll a production per cell. Furthermore, biomolecules like total proteins, carbohydrates and lipids increased with increasing N limitation and Cd stress. Ketogenic and glucogenic amino acids were accumulated under the stress conditions investigated in the present study. Amino acids involved in metal chelation like proline, histidine and glutamine were significantly increased after exposure to combined Cd stress and N limitation. We conclude that N limitation and Cd stress affects the physiology of C. vulgaris by not only decreasing its growth but also stimulating biomolecule production.

Performance of purifying anaerobic fermentation slurry using microalgae in response to various LED light wavelengths and intensities

AbstractBACKGROUNDAnaerobic fermentation slurry (AFS) is a type of high‐pollution load wastewater that can cause water eutrophication and algal blooms. The current study focused on the response of microalgae nutrient removal efficiency to various light‐emitting diode light wavelengths and intensities.RESULTSThe microalgae Chlorella vulgaris was able to remove nutrients from AFS effectively. Furthermore, only moderate light intensities (800, 1300, 1800, and 2300 µmol m−2 s−1) were required to culture C. vulgaris and induce nutrient removal. Exposure to higher light intensities produced greater dry weight (DW) biomass and achieved higher nutrient removal efficiencies. The order of light wavelengths based on the DW biomass yield of C. vulgaris was red &gt; white &gt; yellow &gt; blue. The order of light wavelengths, according to the nutrient removal efficiencies reached by C. vulgaris, was red &gt; white &gt; yellow &gt; blue. Red light was also the light wavelength with the best economic efficiency for nutrient removal.CONCLUSIONIn this study, red light was used as the optimum light wavelength. Furthermore, the optimum light intensity range was from 1300 to 1800 µmol m−2 s−1 when both nutrient removal and economic efficiencies were considered.Moreover, the optimum treatment time was determined to be 120 h. © 2012 Society of Chemical Industry

Yangtze River floods enhance coastal ocean phytoplankton biomass and potential fish production

[1] The occurrence of extreme weather conditions appears on the rise under current climate change conditions, resulting in more frequent and severe floods. The devastating floods in southern China in 2010 and eastern Australia 2010–2011, serve as a solemn testimony to that notion. Accompanying the excess runoffs, elevated amount of terrigenous materials, including nutrients for microalgae, are discharged to the coastal ocean. However, how these floods and the materials they carry affect the coastal ocean ecosystem is still poorly understood. Yangtze River (aka Changjiang), which is the largest river in the Eurasian continent, flows eastward and empties into the East China Sea. Since the early twentieth century, serious overflows of the Changjiang have occurred four times. During the two most recent ones in July 1998 and 2010, we found total primary production in the East China Sea reaching 147 × 103 tons carbon per day, which may support fisheries catch as high as 410 × 103 tons per month, about triple the amount during non-flooding periods based on direct field oceanographic observations. As the frequencies of floods increase world wide as a result of climate change, the flood-induced biological production could be a silver lining to the hydrological hazards and human and property losses inflicted by excessive precipitations.