Research

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12 pages, 2454 KiB

Open AccessArticle

Selenastrum Capricornutum a New Strain of Algae for Biodiesel Production

by Annarita Pugliese, Lorenzo Biondi, Pietro Bartocci and Francesco Fantozzi

Fermentation 2020, 6(2), 46; https://doi.org/10.3390/fermentation6020046 - 26 Apr 2020

Cited by 23 | Viewed by 4837

The increasing global demand for biofuels for energy security and to reduce the effects of climate change has created an opportunity to explore new sources of biomass, of which, microalgae is the most promising one. The Laboratory of the Biomass Research Centre (CRB, [...] Read more.

The increasing global demand for biofuels for energy security and to reduce the effects of climate change has created an opportunity to explore new sources of biomass, of which, microalgae is the most promising one. The Laboratory of the Biomass Research Centre (CRB, University of Perugia) is equipped with a photobioreactor that is used to cultivate microalgae under batch conditions. Tests were carried out a temperature of 22 °C and a Photosynthetic Photon Flux Density of 140 µE·m⁻²·s⁻¹. Cultures were characterized in terms of biomass produced and lipid fraction distribution. The novelty of this paper is the measure of the fuel properties of Selenastrum capricornutum, a new strain for biodiesel production. In particular, after the microalgae have been collected and oil has been extracted, this has been transesterified using a methanol/NaOH solution. The resulting biodiesel has been analyzed with a high-resolution gas chromatograph to determine the concentration of the different methylesters. Full article

(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)

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9 pages, 2830 KiB

Open AccessArticle

Catalytic Effect of Functional and Fe Composite Biochars on Biofuel and Biochemical Derived from the Pyrolysis of Green Marine Biomass

by Omid Norouzi and Francesco Di Maria

Fermentation 2018, 4(4), 96; https://doi.org/10.3390/fermentation4040096 - 17 Nov 2018

Cited by 14 | Viewed by 3975

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 [...] Read more.

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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9 pages, 786 KiB

Open AccessFeature PaperArticle

Co-Culture of Filamentous Feed-Grade Fungi and Microalgae as an Alternative to Increase Feeding Value of Ethanol Coproducts

by Cristiano E. Rodrigues Reis, Larissa Ogero D’Otaviano, Aravindan Rajendran and Bo Hu

Fermentation 2018, 4(4), 86; https://doi.org/10.3390/fermentation4040086 - 11 Oct 2018

Cited by 8 | Viewed by 4284

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 [...] Read more.

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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4107 KiB

Open AccessArticle

Optimization of Arthrospira platensis (Spirulina) Growth: From Laboratory Scale to Pilot Scale

by Florian Delrue, Emilie Alaux, Lagia Moudjaoui, Clément Gaignard, Gatien Fleury, Amaury Perilhou, Pierre Richaud, Martin Petitjean and Jean-François Sassi

Fermentation 2017, 3(4), 59; https://doi.org/10.3390/fermentation3040059 - 07 Nov 2017

Cited by 67 | Viewed by 13230

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 [...] Read more.

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 mg_Fe/L (2.11 ± 0.13 mg_Fe/g_biomass for EDTA-FeNa, 3 H₂O at 10 mg_Fe/L compared to 0.18 ± 0.13 for FeSO₄,6H₂O at 2 mg_Fe/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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31 pages, 1885 KiB

Open AccessReview

A Review of Seaweed Pre-Treatment Methods for Enhanced Biofuel Production by Anaerobic Digestion or Fermentation

by Supattra Maneein, John J. Milledge, Birthe V. Nielsen and Patricia J. Harvey

Fermentation 2018, 4(4), 100; https://doi.org/10.3390/fermentation4040100 - 29 Nov 2018

Cited by 89 | Viewed by 15957

Abstract

Macroalgae represent a potential biomass source for the production of bioethanol or biogas. Their use, however, is limited by several factors including, but not restricted to, their continuous supply for processing, and low biofuel yields. This review examines recent pre-treatment processes that have [...] Read more.

Macroalgae represent a potential biomass source for the production of bioethanol or biogas. Their use, however, is limited by several factors including, but not restricted to, their continuous supply for processing, and low biofuel yields. This review examines recent pre-treatment processes that have been used to improve the yields of either biogas or bioethanol from macroalgae. Factors that can influence hydrolysis efficiency and, consequently, biofuel yields, are highly affected by macroalgal composition, including content of salts, heavy metals, and polyphenols, structural make-up, as well as polysaccharide composition and relative content of carbohydrates. Other factors that can influence biofuel yield include the method of storage and preservation. Full article

(This article belongs to the Special Issue Cultivation and Downstream Processing of Algal Biomass)

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12 pages, 508 KiB

Open AccessReview

Harvesting of Microalgae by Flocculation

by Irena Branyikova, Gita Prochazkova, Tomas Potocar, Zuzana Jezkova and Tomas Branyik

Fermentation 2018, 4(4), 93; https://doi.org/10.3390/fermentation4040093 - 09 Nov 2018

Cited by 129 | Viewed by 10937

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 [...] Read more.

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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17 pages, 1764 KiB

Open AccessReview

Exploitation of Microalgae Species for Nutraceutical Purposes: Cultivation Aspects

by Sushanta Kumar Saha and Patrick Murray

Fermentation 2018, 4(2), 46; https://doi.org/10.3390/fermentation4020046 - 14 Jun 2018

Cited by 45 | Viewed by 8490

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 [...] Read more.

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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15 pages, 841 KiB

Open AccessReview

Phytohormones and Effects on Growth and Metabolites of Microalgae: A Review

by Xingfeng Han, Huiru Zeng, Pietro Bartocci, Francesco Fantozzi and Yunjun Yan

Fermentation 2018, 4(2), 25; https://doi.org/10.3390/fermentation4020025 - 09 Apr 2018

Cited by 99 | Viewed by 12513

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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