Special Issue "Cultivation and Downstream Processing of Algal Biomass"

A special issue of Fermentation (ISSN 2311-5637).

Deadline for manuscript submissions: closed (30 September 2018)

Special Issue Editors

Guest Editor
Prof. Dr. Tomáš Brányik

Department of Biotechnology, University of Chemistry and Technology Prague, Czech Republic
Website | E-Mail
Interests: surface interactions of microorganisms (adhesion, immobilization, biofilms, flocculation); biotechnology of microalgae; continuous bioreactors; formation and decay of beer foam
Guest Editor
Dr. Pietro Bartocci

Department of Engineering, University of Perugia, Via G. Duranti 67, Perugia 06125, Italy
Website 1 | Website 2 | E-Mail
Interests: biomass; bioenergy; biogas; anaerobic digestion; pyrolysis; kinetics

Special Issue Information

Dear Colleagues,

Microalgae are a group of organisms that are physiologically and morphologically heterogeneous. High growth rate, high photosynthetic efficiency, content of biologically active and energy-rich chemicals, experience with large-scale cultivation, and down-stream processing technologies have focused increased attention on microalgae. Lipids for biodiesel or as a feedstock for the chemical industry, ω-3 fatty acids, proteins, carbohydrates, pigments, biohydrogen, bioethanol, food supplements, animal feed, etc., are only a few examples of the wide-ranging potential for microalgae. However, there are only a few commercially-successful microalgal technologies, since the production costs of microalgae delimit their application only to high-value products. To improve the economic feasibility of microalgal biotechnologies, the production costs have to be reduced significantly. The development of an economically feasible industrial-scale production of microalgae, or products derived from them, requires a complex multidisciplinary approach.

While microalgae are unicellular organisms, macroalgae (or seaweed) are multicellular macroscopic organisms, which can be classified into red, green, and brown algae. Macroalgae proliferation can be unwanted in the case of eutrophication in rivers, lakes, and maritime basins. However, macroalgae can at the same time be the solution to the eutrophication problem, because they absorb excess nutrients and, therefore, they clean the same polluted waters. Like microalgae, also macroalgae can be used to produce biofuels and chemicals and they are a source of carbohydrates, proteins, and lipids. In addition, macroalgae can also provide food and nutrients to different organisms, including humans. The main steps in the cultivation and use of macroalgae are: species selection, production of juvenile algae, growth, harvest, transport, and further treatment. The whole supply chain has to be carefully analyzed to understand if the use of macroalgae in the green chemistry industry is economically, socially, and environmentally feasible.

In this Special Issue, we invite authors to submit original research and review articles that increase our understanding of photobioreactors and other technologies for the production of microalgal biomass. Some of the topics of interest are: the correlation between eutrophication and macroalgae formation, the methods of harvesting macro- and microalgae, and the downstream processing techniques of the algal biomass for product recovery. Further, original research articles and reviews focused on products from macro- and microalgae, macro- and microalgae for human and animal consumption, macro- and microalgae for novel foods and food supplements, macro- and microalgae as a source of fine chemicals, and their use in environmental applications are welcome. Contributions on potential algal biofuels and biorefineries based on macro- and microalgae are particularly welcome.

Prof. Dr. Tomáš Brányik
Dr. Pietro Bartocci
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Fermentation is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) is waived for well-prepared manuscripts submitted to this issue. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Microalgae
  • Macroalgae
  • Production of algal biomass
  • Downstream processing
  • Bioproducts
  • Biofuels
  • Biorefineries
  • Environmental applications of macro- and microalgae

Published Papers (6 papers)

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Research

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Open AccessArticle Catalytic Effect of Functional and Fe Composite Biochars on Biofuel and Biochemical Derived from the Pyrolysis of Green Marine Biomass
Fermentation 2018, 4(4), 96; https://doi.org/10.3390/fermentation4040096 (registering DOI)
Received: 20 September 2018 / Revised: 29 October 2018 / Accepted: 8 November 2018 / Published: 17 November 2018
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Abstract
This study investigated the behavior of two types of modified biochar (functional and iron composite biochars) as a catalyst regarding their surface chemistry and morphological properties and their effects on bio-product derived from pyrolysis of Cladophora glomerata (C. glomerata) macroalagae. Two
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This study investigated the behavior of two types of modified biochar (functional and iron composite biochars) as a catalyst regarding their surface chemistry and morphological properties and their effects on bio-product derived from pyrolysis of Cladophora glomerata (C. glomerata) macroalagae. Two catalytic pyrolysis experiments were conducted in 25 mL slow pyrolysis reactor in the presence of biochar-based catalysts at the temperature of 500 °C. For functional biochar, no clear effect on biogas production was observed, whereas iron composite biochar increased the hydrogen content by 7.99 mml/g algae. Iron composite biochar with a 3D network structure demonstrated remarkable catalytic behaviors (especially toward hydrogen production) due to its wonderful surface area, high dispersion of iron particles and particular structures and compositions. The biochar derived marine biomass and treatment process developed here could provide a promising path for the low-cost, efficient, renewable and environmental friendly catalysts. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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Open AccessFeature PaperArticle Co-Culture of Filamentous Feed-Grade Fungi and Microalgae as an Alternative to Increase Feeding Value of Ethanol Coproducts
Fermentation 2018, 4(4), 86; https://doi.org/10.3390/fermentation4040086
Received: 24 September 2018 / Revised: 5 October 2018 / Accepted: 9 October 2018 / Published: 11 October 2018
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Abstract
Distiller’s grains, an important commodity in the feed and food chains, are currently underdosed in rations due to several factors, mainly nutrient imbalance. This study aimed to increase the linoleic acid content in distiller’s grains and decrease the excess nutrients in stillage water
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Distiller’s grains, an important commodity in the feed and food chains, are currently underdosed in rations due to several factors, mainly nutrient imbalance. This study aimed to increase the linoleic acid content in distiller’s grains and decrease the excess nutrients in stillage water by the use of an artificial lichen, composed of fungi, algae, and a supporting matrix. A maximum concentration of 46.25% of linoleic acid in distiller’s grains was achieved with a combination of Mucor indicus and Chlorella vulgaris using corn-to-ethanol whole stillage as substrate. Microbial hydrolytic enzymes during fermentation were able to decrease the solids in whole stillage. Nitrogen depletion by microalgal uptake causes lipid-formation stress to Mucor indicus cells, increasing linoleic acid production to about 49% of the total lipids, potentially decreasing costs in the animal feed. The culture supernatant can potentially be recycled as process water to the ethanol fermentation tank, and enhanced distiller’s grains can replace animal-specific diets. This would reduce exogenous enzyme use and supplementation of unsaturated fatty acids from other sources. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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Open AccessArticle Optimization of Arthrospira platensis (Spirulina) Growth: From Laboratory Scale to Pilot Scale
Fermentation 2017, 3(4), 59; https://doi.org/10.3390/fermentation3040059
Received: 12 October 2017 / Revised: 1 November 2017 / Accepted: 2 November 2017 / Published: 7 November 2017
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Abstract
Arthrospira platensis (Spirulina) is the most cultivated microalga worldwide. Improving its cultivation in terms of biomass productivity, quality, or production cost could significantly impact the Spirulina industry. The objectives of this paper were defined as to contribute to this goal. Spirulina biomass productivity
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Arthrospira platensis (Spirulina) is the most cultivated microalga worldwide. Improving its cultivation in terms of biomass productivity, quality, or production cost could significantly impact the Spirulina industry. The objectives of this paper were defined as to contribute to this goal. Spirulina biomass productivity was investigated through medium choice. A modified Zarrouk’s medium was selected as it gave higher final dry weights and longer sustained growth than Hiri’s and Jourdan’s media. Then, in order to reduce Spirulina production cost, modified Zarrouk’s medium was rationalized by testing different dilutions. It was found that modified Zarrouk’s medium could be diluted up to five times without impacting the growth rates in a 28-days batch cultivation. Higher dry weights were even observed after 21 days of batch cultivation (1.21 g/L for 20%-modified Zarrouk’s medium in comparison to 0.84 g/L for modified Zarrouk’s medium). Iron uptake was then investigated as one of the major contributors to Spirulina nutritional quality. An increase in iron content was obtained by replacing iron sulfate by iron EDTA at a concentration of 10 mgFe/L (2.11 ± 0.13 mgFe/gbiomass for EDTA-FeNa, 3 H2O at 10 mgFe/L compared to 0.18 ± 0.13 for FeSO4,6H2O at 2 mgFe/L). Impact of light intensity on Spirulina biomass productivity was also investigated in a 2 L Photobioreactor (PBR). Specific growth rates were calculated for Photosynthetically Photon Flux Densities (PPFD) from 85 to 430 µmol/m2/s. At 430 µmol/m2/s, photoinhibition was not observed and the specific growth rate was maximum (0.12/day). Finally, a 40-day cultivation experiment was conducted in a 1000 L PBR giving a maximum daily areal productivity of 58.4 g/m2/day. A techno-economic analysis gave production cost two to 20 times higher for PBR (from 18.71 to 74.29 €/kg) than for open ponds (from 3.86 to 9.59 €/kg) depending on Spirulina productivity. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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Review

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Open AccessReview Harvesting of Microalgae by Flocculation
Fermentation 2018, 4(4), 93; https://doi.org/10.3390/fermentation4040093
Received: 16 October 2018 / Revised: 5 November 2018 / Accepted: 7 November 2018 / Published: 9 November 2018
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Abstract
Due to increasing demands for microalgal biomass and products originating from microalgae, large-scale production systems are necessary. However, current microalgal production technologies are not cost-effective and are hindered by various bottlenecks, one of which is the harvesting of microalgal biomass. Cell separation is
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Due to increasing demands for microalgal biomass and products originating from microalgae, large-scale production systems are necessary. However, current microalgal production technologies are not cost-effective and are hindered by various bottlenecks, one of which is the harvesting of microalgal biomass. Cell separation is difficult because of the low sedimentation velocity of microalgae, their colloidal character with repelling negative surface charges, and low biomass concentrations in culture broths; therefore, large volumes need to be processed in order to concentrate the cells. Flocculation is considered to be one of the most suitable methods for harvesting microalgal biomass. This article provides an overview of flocculation methods suitable for microalgal harvesting, their mechanisms, advantages and drawbacks. Special attention is paid to the role of surface charge in the mechanism of flocculation. The novelty of the review lies in the interconnection between the context of technological applications and physico-chemical surface phenomena. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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Open AccessReview Exploitation of Microalgae Species for Nutraceutical Purposes: Cultivation Aspects
Fermentation 2018, 4(2), 46; https://doi.org/10.3390/fermentation4020046
Received: 2 May 2018 / Revised: 7 June 2018 / Accepted: 12 June 2018 / Published: 14 June 2018
Cited by 1 | PDF Full-text (1764 KB) | HTML Full-text | XML Full-text
Abstract
Cyanobacteria and microalgae have been cultivated only for a limited number of bioactive compounds or biotechnological applications such as for carotenoids; essential omega-3 fatty acids; phycobilipigments; live cells, unprocessed or minimally processed complete biomass as aqua feed, animal feed and human health supplements
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Cyanobacteria and microalgae have been cultivated only for a limited number of bioactive compounds or biotechnological applications such as for carotenoids; essential omega-3 fatty acids; phycobilipigments; live cells, unprocessed or minimally processed complete biomass as aqua feed, animal feed and human health supplements as rich sources of proteins, carbohydrates, pigments, vitamins and minerals. However, cyanobacteria and microalgae have been reported through several research investigations as a potential source for various bioactive molecules with marketable nutraceutical and pharmaceutical properties. Therefore, more cultivation of cyanobacteria and microalgae species are waiting for new biotechnological applications. At present, the global demand for microalgal applications is focused on biofuels including biodiesel and bioethanol apart from a handful (mentioned above) of bioactive compounds which are mostly used as nutraceuticals. Thus, microalgal biorefinery is growing rapidly for multiple commodities production from both conventional and photobioreactor-based cultivation for biomass feedstocks for various biotechnological applications. This review presents the cultivation aspects of selected cyanobacteria and microalgae for commercial purposes. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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Open AccessReview Phytohormones and Effects on Growth and Metabolites of Microalgae: A Review
Fermentation 2018, 4(2), 25; https://doi.org/10.3390/fermentation4020025
Received: 13 March 2018 / Revised: 31 March 2018 / Accepted: 4 April 2018 / Published: 9 April 2018
Cited by 2 | PDF Full-text (841 KB) | HTML Full-text | XML Full-text
Abstract
Microalgae cultivation is booming in agriculture, aquaculture, and bioenergy sectors. A wide range of bioactive compounds with attractive properties can be produced with microalgae, including pigments, vitamins, proteins, carbohydrates, and lipids. The biofuel yields from microalgae can exceed the yields obtained with energy
[...] Read more.
Microalgae cultivation is booming in agriculture, aquaculture, and bioenergy sectors. A wide range of bioactive compounds with attractive properties can be produced with microalgae, including pigments, vitamins, proteins, carbohydrates, and lipids. The biofuel yields from microalgae can exceed the yields obtained with energy crops by 10–100 times. Therefore, such cultivation is promising for the regulation of the biosynthesis of microalagae with phytohormones, which can enhance the production of high-valued bioproducts. This review reports the effect of auxins, abscisic acid, cytokinins, gibberellins, and ethylene on microalgal growth and metabolites, as well as the crosstalk of different phytohormones. The use of phytohormones is also promising because it can also reduce the inputs necessary to grow the selected microalgae and maximize the yields. Full article
(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)
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