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15 pages, 687 KiB

Open AccessArticle

Evaluation of the Prospects for the Use of Microalgae in Functional Bread Production

by Stanislav Sukhikh, Svetlana Ivanova, Vyacheslav Dolganyuk, Inna Pilevinova, Alexander Prosekov, Elena Ulrikh, Svetlana Noskova, Philippe Michaud and Olga Babich

Appl. Sci. 2022, 12(24), 12563; https://doi.org/10.3390/app122412563 - 8 Dec 2022

Cited by 5 | Viewed by 2316

Abstract

Microalgae are widely used to produce sorbitol, ethyl and methyl alcohols, acetone, organic acids, esters, pigments, chlorophylls, carotenoids, and other compounds. The purpose of this work was to study the potential of the Baltic Sea microalgae Arthrospira platensis and Chlorella vulgaris, as new [...] Read more.

Microalgae are widely used to produce sorbitol, ethyl and methyl alcohols, acetone, organic acids, esters, pigments, chlorophylls, carotenoids, and other compounds. The purpose of this work was to study the potential of the Baltic Sea microalgae Arthrospira platensis and Chlorella vulgaris, as new ingredients for functional bread. Bread was baked with a dry mixture of Arthrospira platensis and Chlorella vulgaris microalgae (1:1). Gas chromatography, sequencing, chromametry, pH-metry, rheological methods, methods for determining the antioxidant ability of bread samples with microalgae for ferric reduction and removal of active free radicals were used for the research. When baking bread, the organoleptic, physicochemical properties, density, coefficients of elasticity, chewiness, stickiness, resistance to crumbling, the content of polyphenols and volatile compounds in the samples of bread with microalgae were controlled. It was found that with a higher content of microalgae in bread (3% of the flour weight on dry basis), the color of the crust and crumb decreased due to the degradation of the pigment during baking. The specific volume of a loaf with a large amount of microalgae (5%) was lower than the volume of loaves with the addition of 1% and 3% microalgae. It is shown that the moisture content increased with an increase in the amount of microalgae in bread. Replacing wheat flour with the amounts of microalgae of 1% and 3% did not affect the pH and water activity in bread. With the addition of 5% microalgae, bread became more sour, sticky, with a slight “fishy” smell. The addition of more microalgae led to an increase in polyphenols in bread samples, and, accordingly, to an increased antioxidant capacity. In total, 42 volatile compounds were found in bread with microalgae, which makes it possible to obtain functional bread. It is assumed that in the future, bread with microalgae will be competitive with ordinary wheat bread due to improved nutritional and biological value. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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16 pages, 2165 KiB

Open AccessArticle

Microalgae Cultivation on Nutrient Rich Digestate: The Importance of Strain and Digestate Tailoring under PH Control

by Fleuriane Fernandes, Alla Silkina, José Ignacio Gayo-Peláez, Rahul Vijay Kapoore, Denis de la Broise and Carole A. Llewellyn

Appl. Sci. 2022, 12(11), 5429; https://doi.org/10.3390/app12115429 - 27 May 2022

Cited by 21 | Viewed by 3835

Abstract

The bioremediation of digestate using microalgae presents a solution to the current eutrophication issue in Northwest Europe, where the use of digestate as soil fertiliser is limited, thus resulting in an excess of digestate. Ammonium is the main nutrient of interest in digestate [...] Read more.

The bioremediation of digestate using microalgae presents a solution to the current eutrophication issue in Northwest Europe, where the use of digestate as soil fertiliser is limited, thus resulting in an excess of digestate. Ammonium is the main nutrient of interest in digestate for microalgal cultivation, and improving its availability and consequent uptake is crucial for optimal bioremediation. This work aimed to determine the influence of pH on ammonium availability in cultures of two green microalgae, additionally screened for their growth performances on three digestates produced from different feedstocks, demonstrating the importance of tailoring a microalgal strain and digestate for bioremediation purposes. Results showed that an acidic pH of 6–6.5 resulted in a better ammonium availability in the digestate media, translated into better growth yields for both S. obliquus (GR: 0.099 ± 0.001 day⁻¹; DW: 0.23 ± 0.02 g L⁻¹) and C. vulgaris (GR: 0.09 ± 0.001 day⁻¹; DW: 0.49 ± 0.012 g L⁻¹). This result was especially true when considering larger-scale applications where ammonium loss via evaporation should be avoided. The results also demonstrated that digestates from different feedstocks resulted in different growth yields and biomass composition, especially fatty acids, for which, a digestate produced from pig manure resulted in acid contents of 6.94 ± 0.033% DW and 4.91 ± 0.3% DW in S. obliquus and C. vulgaris, respectively. Finally, this work demonstrated that the acclimation of microalgae to novel nutrient sources should be carefully considered, as it could convey significant advantages in terms of biomass composition, especially fatty acids and carbohydrate, for which, this study also demonstrated the importance of harvesting time. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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14 pages, 1909 KiB

Open AccessArticle

Malaysian Virgin Soil Extracts as Natural Growth Enhancer for Targeted Green Microalgae Species

by Maegala Nallapan Maniyam, Hasdianty Abdullah, Mohd Fadzli Ahmad, Emi Fazlina Hashim, Fridelina Sjahrir, Kazuhiro Komatsu, Victor S. Kuwahara and Nor Suhaila Yaacob

Appl. Sci. 2022, 12(8), 4060; https://doi.org/10.3390/app12084060 - 17 Apr 2022

Cited by 1 | Viewed by 2015

Abstract

The microalgae-based industries are trending upwards, particularly as the feed ingredient for aquaculture. Therefore, a sustainable and reasonably priced source of nutrients to support the mass cultivation of microalgae is in great demand. The present study explored the feasibility of using extracts from [...] Read more.

The microalgae-based industries are trending upwards, particularly as the feed ingredient for aquaculture. Therefore, a sustainable and reasonably priced source of nutrients to support the mass cultivation of microalgae is in great demand. The present study explored the feasibility of using extracts from virgin soil as natural growth-promoting nutrients for the cultivation of Nannochloropsis oculata, Nannochloropsis oceanica, and Chlorella sorokiniana. The extracts were obtained from Bera Lake Forest using five different treatment methods. The greatest retrieval of dissolved organic carbon, total dissolved nitrogen, and total dissolved phosphorus were observed with the autoclave treatment method at 121 °C twice, yielding a respective concentration of 336.56 mg/L, 13.40 mg/L, and 0.14 mg/L, respectively. The highest growth was recorded with Nannochloropsis oculata resulting in an optical density of 0.488 ± 0.009 (×10³ cell mL⁻¹), exhibiting 43% and 44% enhanced growth in comparison to Nannochloropsis oceanica and Chlorella sorokiniana, respectively. The specific growth rate (0.114 ^a ± 0.007 d⁻¹) was the highest for Nannochloropsis oculata when the 24 h-extraction method was used, whereas the utilization of the autoclave 121 °C twice treatment method contributed to the highest specific growth of Nannochloropsis ocenica (0.069 ^a ± 0.003 d⁻¹) and Chlorella sorokiniana (0.080 ^a ± 0.001 d⁻¹). Collectively, these findings suggested that the addition of soil extracts which is sustainable and inexpensive promoted the growth of microalgae compared to the control system. A further study investigating the optimum culture conditions for enhanced microalgae growth will be carried out for the mass production of microalgae biomass. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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12 pages, 1816 KiB

Open AccessArticle

Production of Docosahexaenoic Acid and Odd-Chain Fatty Acids by Microalgae Schizochytrium limacinum Grown on Waste-Derived Volatile Fatty Acids

by Laura Oliver, Laura Fernández-de-Castro, Thomas Dietrich, Maria Carmen Villaran and Ramón J. Barrio

Appl. Sci. 2022, 12(8), 3976; https://doi.org/10.3390/app12083976 - 14 Apr 2022

Cited by 10 | Viewed by 2291

Abstract

Heterotrophic microalgae are recognized as a source of bioactive compounds. However, there are still some drawbacks for their use at an industrial scale associated with the high cost of glucose, the main carbon source in heterotrophic cultures. In recent years, significant efforts have [...] Read more.

Heterotrophic microalgae are recognized as a source of bioactive compounds. However, there are still some drawbacks for their use at an industrial scale associated with the high cost of glucose, the main carbon source in heterotrophic cultures. In recent years, significant efforts have been made to investigate more sustainable carbon sources to produce biomass. In this study, the capacity of Schizochytrium limacinum to grow on waste-derived volatile fatty acids and the effect that their use produces on biomass and fatty acids profiles were investigated. Acetic, propionic, butyric, valeric and caproic acid were evaluated independently, as well as in a synthetic mixture (VFA). The use of acetic and butyric resulted in a good biomass productivity, while the use of valeric and propionic acid resulted in higher content of odd-chain fatty acids (OCFA), increasingly investigated due to their potential benefits for human health. The use of industrial waste-derived VFA as a potential carbon source was validated through the utilization of biowaste derived effluents from a volatile fatty acid platform. The biomass produced was of 18.5 g/L, 54.0% lipids, 46.3% docosahexaenoic acid (DHA) and 25.0% OCFA, concluding that waste derived VFA can produce DHA and OCFA in a suitable ratio of DHA/OCFA with potential industrial applications. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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12 pages, 1915 KiB

Open AccessArticle

Application of Chlorella sp. and Scenedesmus sp. in the Bioconversion of Urban Leachates into Industrially Relevant Metabolites

by Jeimy J. Ortiz-Betancur, Marla S. Herrera-Ochoa, Janet B. García-Martínez, Néstor A. Urbina-Suarez, Germán L. López-Barrera, Andrés F. Barajas-Solano, Samantha J. Bryan and Antonio Zuorro

Appl. Sci. 2022, 12(5), 2462; https://doi.org/10.3390/app12052462 - 26 Feb 2022

Cited by 2 | Viewed by 2045

Abstract

This paper explores the ability of Chlorella sp. and Scenedesmus sp. to convert landfill leachates into usable metabolites. Different concentrations (0.5, 1, 5, and 10% v/v) of leachate coupled with an inorganic carbon source (Na₂CO₃, and [...] Read more.

This paper explores the ability of Chlorella sp. and Scenedesmus sp. to convert landfill leachates into usable metabolites. Different concentrations (0.5, 1, 5, and 10% v/v) of leachate coupled with an inorganic carbon source (Na₂CO₃, and NaHCO₃) were tested to improve biomass production, metabolites synthesis, and removal of NO₃ and PO₄. The result shows that both strains can effectively grow in media with up to 5% (v/v) leachate, while significantly reducing the concentrations of NO₃, and PO₄ (80 and 50%, respectively). The addition of NaHCO₃ as a carbon source improved the final concentration of biomass, lipids, carbohydrates, and the removal of NO₃ and PO₄ in both strains. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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9 pages, 716 KiB

Open AccessArticle

Microwave-Assisted Extraction of Fatty Acids from Cultured and Commercial Phytoplankton Species

by Jéssica Aparecida Moretto, Alexander Ossanes de Souza, Lucas Moraes Berneira, Luiz Gustavo G. Brigagão, Claudio Martin Pereira de Pereira, Attilio Converti and Ernani Pinto

Appl. Sci. 2022, 12(5), 2407; https://doi.org/10.3390/app12052407 - 25 Feb 2022

Cited by 7 | Viewed by 2309

Abstract

(1) Background: The extraction of fatty acids from microalgae and cyanobacteria is mostly performed with organic solvents and laborious procedures. Microwave-assisted extraction (MAE) can be a more effective and environmentally friendly process than traditional extraction (TE), which uses a large volume of solvent [...] Read more.

(1) Background: The extraction of fatty acids from microalgae and cyanobacteria is mostly performed with organic solvents and laborious procedures. Microwave-assisted extraction (MAE) can be a more effective and environmentally friendly process than traditional extraction (TE), which uses a large volume of solvent and conduction heating. Freshwater phytoplankton inhabits diverse aquatic environments and is a promising source of fatty acids and green precursors in the synthesis of biofuel, including cyanobacterial biomass. Therefore, the aim of this study was to investigate the potential of MAE to extract fatty acids from a Chlorella sp. microalga and two cyanobacteria, namely, Arthrospira sp. and Sphaerospermopsis torques-reginae, for biodiesel production. For this purpose, the lipid content and fatty acid profile of these strains were compared after treating biomass with the two extraction methods. (2) Methods: MAE and TE were used as extraction procedures; gas chromatography–mass spectrometry was used to assess the fatty acid profiles, and X-ray spectroscopy was used to analyze biomass. (3) Results: Although the fatty acid profile of the oil obtained by TE showed higher concentrations of fatty acids, the MAE method was able to extract more types of fatty acids. The variety of fatty acids extracted by the MAE, especially those with unsaturated chains, allowed for better quality biodiesel, presenting advantages over previous methods and studies. According to the analyses, essential fatty acids 16:0, 16:1, and 18:2 were found to be abundant in both cyanobacterial strains and in microalga, showing potential for biofuel production. Additionally, metal composition was determined as its content may indicate potential pro-oxidant influence in biofuel production. (4) Conclusions: MAE is a useful and green strategy to extract fatty acids from freshwater phytoplankton. Cyanobacteria can also be a beneficial source of fatty acids for biodiesel synthesis. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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14 pages, 721 KiB

Open AccessArticle

A Two-Step Process for Improved Biomass Production and Non-Destructive Astaxanthin and Carotenoids Accumulation in Haematococcus pluvialis

by Arianna Rizzo, Michael E. Ross, Alessandra Norici and Bruno Jesus

Appl. Sci. 2022, 12(3), 1261; https://doi.org/10.3390/app12031261 - 25 Jan 2022

Cited by 10 | Viewed by 3947

Abstract

Carotenoids extracted from microalgae have a considerable economic interest in numerous high-value markets. Natural astaxanthin has gained much interest in its powerful antioxidant properties, however, its commercial-scale production is still challenging. In this study, a simple and economical way to cultivate Haematococcus pluvialis [...] Read more.

Carotenoids extracted from microalgae have a considerable economic interest in numerous high-value markets. Natural astaxanthin has gained much interest in its powerful antioxidant properties, however, its commercial-scale production is still challenging. In this study, a simple and economical way to cultivate Haematococcus pluvialis (CCAP 34/1D) by a two-step process was investigated by exploring alternative strategies to maximise algal growth and astaxanthin yield. During the first step—improving biomass production—four nitrogen sources were tested (NH₄Cl, NaNO₃, Fe(III)NO₃, and urea). The second step—carotenogenesis induction—was achieved by using a mix of moderate stressors that worked in synergy (i.e., mild light, nitrogen limitation, the addition of sodium acetate at 0.25% w/v), thereby minimising potential losses of the accumulated biomass caused, for example, by photobleaching or nitrogen starvation. Results showed that urea was the nitrogen source, allowing the highest cell density and growth rate. In terms of carotenogenesis induction, the use of mild stressors resulted in three out of four treatments having a relative increase in cell number (13.8–26.7%) and a concomitant increase in astaxanthin yield. Simple low-cost strategies, such as small adjustments to media recipes and synergism between mild stressors, could bring a disproportionate effect on the future successes of making algal biotechnology a widespread reality. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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12 pages, 1572 KiB

Open AccessArticle

Elusive Recurrent Bacterial Contamination in a Diatom Culture: A Case Study

by Alexey A. Morozov, Yuri P. Galachyants, Artyom M. Marchenkov, Darya P. Petrova and Yulia R. Zakharova

Appl. Sci. 2021, 11(21), 10131; https://doi.org/10.3390/app112110131 - 28 Oct 2021

Viewed by 1946

Abstract

In preparation for whole-genome sequencing, the axenic culture for two strains of a freshwater diatom Fragilaria radians were produced. Although their axenicity was controlled for the cultures’ entire lifetime, the published genomic assembly was later found to contain a large amount of bacterial [...] Read more.

In preparation for whole-genome sequencing, the axenic culture for two strains of a freshwater diatom Fragilaria radians were produced. Although their axenicity was controlled for the cultures’ entire lifetime, the published genomic assembly was later found to contain a large amount of bacterial sequences. Using various in silico analyses of whole genome read libraries and 16S rRNA sequencing of culture samples, we reconstruct the history of the contamination and document the failures of various axenicity control methods. This knowledge is used to discuss how these failures could have been avoided, and to provide guidelines for future works on axenic diatom cultures. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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15 pages, 1718 KiB

Open AccessArticle

Effects from Converter Slag and Electric Arc Furnace Slag on Chlorophyll a Accumulation of Nannochloropsis sp.

by Tianji Liu, Yitong Wang, Junguo Li, Qing Yu, Xiaoman Wang, Di Gao, Fuping Wang, Shuang Cai and Yanan Zeng

Appl. Sci. 2021, 11(19), 9127; https://doi.org/10.3390/app11199127 - 30 Sep 2021

Cited by 1 | Viewed by 1727

Abstract

The effects of Ca²⁺ in converter slag and electric arc furnace slag leaching solutions on CO₂ content, the effects of CO₂ content in solutions on the accumulation of chlorophyll a of Nannochloropsis sp., and the mechanisms were studied. Results showed [...] Read more.

The effects of Ca²⁺ in converter slag and electric arc furnace slag leaching solutions on CO₂ content, the effects of CO₂ content in solutions on the accumulation of chlorophyll a of Nannochloropsis sp., and the mechanisms were studied. Results showed that addition of 50 mg/L converter slag leaching solution and 400 mg/L electric arc furnace slag leaching solution (lower than 50 vol% concentration) promoted the accumulation of chlorophyll a of Nannochloropsis sp., while an increased concentration of 70 vol% inhibited its accumulation. The highest concentration of chlorophyll a was obtained on the addition of 10 vol%. With 10 vol% leaching solutions added, chlorophyll a concentration for converter slag reached 4.2 mg/L, 1.45 times as much as that of pure F/2 medium, and chlorophyll a concentration for electric arc slag reached 3.2 mg/L, 1.10 times as much as that of pure F/2 medium. Under the same addition proportion, the promoting or inhibiting effect from converter slag on the accumulation of chlorophyll a of Nannochloropsis sp. was more obvious than that for electric arc furnace slag. The reason for the promotion of chlorophyll a accumulation of Nannochloropsis sp. was that an increase of Ca²⁺ in the solutions led to an increase of CO₂, thereby promoting the photosynthetic rate of microalgae. The study provided new ideas for the green application of solid waste and industrial production of microalgae. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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24 pages, 2990 KiB

Open AccessArticle

Production of Microalgal Biomass in Photobioreactors as Feedstock for Bioenergy and Other Uses: A Techno-Economic Study of Harvesting Stage

by Esveidi Montserrat Valdovinos-García, Moisés Abraham Petriz-Prieto, María de los Ángeles Olán-Acosta, Juan Barajas-Fernández, Adriana Guzmán-López and Micael Gerardo Bravo-Sánchez

Appl. Sci. 2021, 11(10), 4386; https://doi.org/10.3390/app11104386 - 12 May 2021

Cited by 16 | Viewed by 3977

Abstract

The cultivation of microalgae has become a viable option to mitigate increase in CO₂ in the atmosphere generated by industrial activities since they can capture CO₂ as a carbon source for growth. Besides, they produce significant amounts of oils, carbohydrates, proteins, [...] Read more.

The cultivation of microalgae has become a viable option to mitigate increase in CO₂ in the atmosphere generated by industrial activities since they can capture CO₂ as a carbon source for growth. Besides, they produce significant amounts of oils, carbohydrates, proteins, and other compounds of economic interest. There are several investigations related to the process, however, there is still no optimal scenario, since may depend on the final use of the biomass. The objective of this work was to develop a techno-economic evaluation of various technologies in harvesting and drying stages. The techno-economic estimation of these technologies provides a variety of production scenarios. Photobioreactors were used considering 1 ha as a cultivation area and a biomass production of 22.66 g/m²/day and a CO₂ capture of 148.4 tons/ha/year was estimated. The production scenarios considered in this study have high energy demand and high operating costs (12.09–12.51 kWh/kg and US $210.05–214.59/kg). These results are mainly a consequence of the use of tubular photobioreactors as a biomass culture system. However, the use of photobioreactors in the production of microalgal biomass allows it to be obtained in optimal conditions for its use in the food or pharmaceutical industry. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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18 pages, 4924 KiB

Open AccessFeature PaperArticle

Cultivating Microalgae in Desert Conditions: Evaluation of the Effect of Light-Temperature Summer Conditions on the Growth and Metabolism of Nannochloropsis QU130

by Hareb Al Jabri, Aumaya Taleb, Raphaelle Touchard, Imen Saadaoui, Vincent Goetz and Jeremy Pruvost

Appl. Sci. 2021, 11(9), 3799; https://doi.org/10.3390/app11093799 - 22 Apr 2021

Cited by 14 | Viewed by 3428

Abstract

Temperature and light are two of the most crucial factors for microalgae production. Variations in these factors alter their growth kinetics, macromolecular composition and physiological properties, including cell membrane permeability and fluidity. The variations define the adaptation mechanisms adopted by the microalgae to [...] Read more.

Temperature and light are two of the most crucial factors for microalgae production. Variations in these factors alter their growth kinetics, macromolecular composition and physiological properties, including cell membrane permeability and fluidity. The variations define the adaptation mechanisms adopted by the microalgae to withstand changes in these environmental factors. In the Qatar desert the temperature varies widely, typically between 10° and 45 °C There are also wide variations in light intensity, with values of over 1500 μmol_hν.m⁻²s⁻¹ in summer. A study of the effects of these thermal and light fluctuations is therefore essential for large-scale outdoor production systems, especially during the summer when temperature and light fluctuations are at their highest. The aim of this work is to study the impact of temperature and light intensity variations as encountered in summer period on the Nannochloropsis QU130 strain, which was selected for its suitability for outdoor cultivation in the harsh conditions of the Qatar desert. It was carried out using lab-scale photobioreactors enabling simulation of both constant and dynamic temperature and light regimes. Biomass productivity, cell morphology and biochemical compositions were examined first in constant conditions, then in typical outdoor cultivation conditions to elucidate the adjustments in cell function in respect of fluctuations. The dynamic light and temperature were shown to have interactive effects. The application of temperature cycles under constant light led to a 13.6% increase in biomass productivity, while a 45% decrease was observed under light and temperature regimes due to the combined stress. In all cases, the results proved that N. sp. QU130 has a high level of adaptation to the wide fluctuations in light and temperature stress. This was shown through its ability to easily change its physiology (cell size) and metabolic process in response to different cultivation conditions. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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Review

Jump to: Research

28 pages, 925 KiB

Open AccessReview

Content of Lipids, Fatty Acids, Carbohydrates, and Proteins in Continental Cyanobacteria: A Systematic Analysis and Database Application

by Larissa Souza Passos, Paloma Nathane Nunes de Freitas, Rafaella Bizo Menezes, Alexander Ossanes de Souza, Milena Fernandes da Silva, Attilio Converti and Ernani Pinto

Appl. Sci. 2023, 13(5), 3162; https://doi.org/10.3390/app13053162 - 1 Mar 2023

Cited by 5 | Viewed by 3690

Abstract

The lipid, fatty acid, protein, and carbohydrate contents in cyanobacterial strains and biomass can vary by orders of magnitude. Many publications (thousands of peer-reviewed articles) require more work to extract their precise concentration values (i.e., different units, inaccurate data), which makes them not [...] Read more.

The lipid, fatty acid, protein, and carbohydrate contents in cyanobacterial strains and biomass can vary by orders of magnitude. Many publications (thousands of peer-reviewed articles) require more work to extract their precise concentration values (i.e., different units, inaccurate data), which makes them not easily exploitable. For this purpose, tables have been compiled from the literature data, including lipids, fatty acids, proteins, and carbohydrates composition and quantities in cyanobacteria. A lot of data (323) were collected after careful a literature search, according to selected criteria in order to distinguish separately cyanobacteria, and according to categories of genus and species and generate average values of the contents of these cell components. These data are exploited in a first systematic analysis of the content in types of strains. Our database can be a powerful tool for biologists, chemists, and environmental agencies to determine the potential concentration of high-value chemical building blocks directly from low-value bloom biomass, cell cultures, or debris in the sediment, offering the potential to minimize environmental waste and add value to the agro-industrial residues. The database can also support strategies for food manufacturers to develop new products with optimized properties for veterinarian applications. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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22 pages, 1414 KiB

Open AccessReview

Sustainable Microalgae and Cyanobacteria Biotechnology

by Jenny-Fabiola López-Hernández, Tan Kean-Meng, Gloria-Gertrudys Asencio-Alcudia, Mohd Asyraf-Kassim, Carlos-Alfonso Alvarez-González and Facundo-Joaquín Márquez-Rocha

Appl. Sci. 2022, 12(14), 6887; https://doi.org/10.3390/app12146887 - 7 Jul 2022

Cited by 8 | Viewed by 4192

Abstract

Marine organisms are a valuable source of new compounds, many of which have remarkable biotechnological properties, such as microalgae and cyanobacteria, which have attracted special attention to develop new industrial production routes. These organisms are a source of many biologically active molecules in [...] Read more.

Marine organisms are a valuable source of new compounds, many of which have remarkable biotechnological properties, such as microalgae and cyanobacteria, which have attracted special attention to develop new industrial production routes. These organisms are a source of many biologically active molecules in nature, including antioxidants, immunostimulants, antivirals, antibiotics, hemagglutinates, polyunsaturated fatty acids, peptides, proteins, biofuels, and pigments. The use of several technologies to improve biomass production, in the first step, industrial processes schemes have been addressed with different accomplishments. It is critical to consider all steps involved in producing a bioactive valuable compound, such as species and strain selection, nutrient supply required to support productivity, type of photobioreactor, downstream processes, namely extraction, recovery, and purification. In general, two product production schemes can be mentioned; one for large amounts of product, such as biodiesel or any other biofuel and the biomass for feeding purposes; the other for when the product will be used in the human health domain, such as antivirals, antibiotics, antioxidants, etc. Several applications for microalgae have been documented. In general, the usefulness of an application for each species of microalgae is determined by growth and product production. Furthermore, the use of OMICS technologies enabled the development of a new design for human therapeutic recombinant proteins, including strain selection based on previous proteomic profiles, gene cloning, and the development of expression networks. Microalgal expression systems have an advantage over traditional microbial, plant, and mammalian expression systems for new and sustainable microalga applications, for responsible production and consumption. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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26 pages, 396 KiB

Open AccessFeature PaperReview

Biomolecules from Microalgae and Cyanobacteria: Applications and Market Survey

by Rihab Hachicha, Fatma Elleuch, Hajer Ben Hlima, Pascal Dubessay, Helene de Baynast, Cedric Delattre, Guillaume Pierre, Ridha Hachicha, Slim Abdelkafi, Philippe Michaud and Imen Fendri

Appl. Sci. 2022, 12(4), 1924; https://doi.org/10.3390/app12041924 - 12 Feb 2022

Cited by 74 | Viewed by 9417

Abstract

Nowadays, microalgae and cyanobacteria have become a promising and sustainable source of useful products, thanks to their richness in bioactive metabolites of high value (antibiotics, toxins, pharmaceutically active compounds, plant growth regulators, and others). These photoautotroph microorganisms generate biomass using photosynthesis. This review, [...] Read more.

Nowadays, microalgae and cyanobacteria have become a promising and sustainable source of useful products, thanks to their richness in bioactive metabolites of high value (antibiotics, toxins, pharmaceutically active compounds, plant growth regulators, and others). These photoautotroph microorganisms generate biomass using photosynthesis. This review, which distinguishes microalgae and Cyanobacteria, often called blue-green microalgae, aims to present their classification and taxonomic diversity as the ecological niches occupied by them. In addition, the usages of open ponds and photobioreactors to produce various microalgae and Cyanobacteria strains and the high-value bioactive compounds from these microorganisms are summarized. Finally, the numerous commercial applications of these phytoplanktons in different fields, such as food, dietary supplements, feed, cosmetic, and biofuel applications, are reviewed. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

16 pages, 308 KiB

Open AccessReview

Effects from Fe, P, Ca, Mg, Zn and Cu in Steel Slag on Growth and Metabolite Accumulation of Microalgae: A Review

by Tianji Liu, Yitong Wang, Junguo Li, Qing Yu, Xiaoman Wang, Di Gao, Fuping Wang, Shuang Cai and Yanan Zeng

Appl. Sci. 2021, 11(14), 6589; https://doi.org/10.3390/app11146589 - 17 Jul 2021

Cited by 16 | Viewed by 3021

Abstract

Steel slag is the solid waste produced by the steelmaking process. At present, there are differences in the treatment and utilization of this waste among countries around the world. The massive accumulation of steel slag not only occupies land, but also the heavy [...] Read more.

Steel slag is the solid waste produced by the steelmaking process. At present, there are differences in the treatment and utilization of this waste among countries around the world. The massive accumulation of steel slag not only occupies land, but also the heavy metal elements in steel slag leached by rainwater cause serious pollution to the soil and groundwater, both which threaten the life and survival of the surrounding residents. More and more attention has been paid to the resource utilization of slag because of the gradual promotion of energy saving and emission reduction all over the world. Currently, the fields that utilize slag focus on recycling of steel waste, acting as sinter raw material, dephosphorization of hot metal, road and water conservancy project construction, wastewater treatment material, application of CO₂ capture and flue gas desulfurization or agriculture. Many researchers have carried out research and explorations on the effects of slag on microalgae’s growth and found that slag has enormous potential algal biomasses and huge advantages for promoting microalgae’s growth and the accumulation of metabolites. Under suitable conditions, slag can effectively promote microalgae’s growth and reproduction, as well as promote microalgae’s accumulation of metabolites, especially lipid accumulation. Thus, slag can be used as an ideal nutrient for microalgae. Culturing microalgae with slag can lower the cost and solve the problem of lacking Fe during the process of marine microalgae’s growth. Meanwhile, it can alleviate the phenomenon of the substantial stacking of slag. This study provides new methods for slag’s resource utilization. Full article

(This article belongs to the Special Issue Advances in Microalgal Biomass Productions)

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