Microalgae dewatering is a major obstruction to industrial-scale processing of microalgae for biofuel prodn. The dil. nature of harvested microalgal cultures creates a huge operational cost during dewatering, thereby, rendering algae-based fuels less economically attractive. Currently there is no superior method of dewatering microalgae. A technique that may result in a greater algal biomass may have drawbacks such as a high capital cost or high energy consumption. The choice of which harvesting technique to apply will depend on the species of microalgae and the final product desired. Algal properties such as a large cell size and the capability of the microalgae to autoflocculate can simplify the dewatering process. This article reviews and addresses the various technologies currently used for dewatering microalgal cultures along with a comparative study of the performances of the different technologies.

Dewatering of microalgal cultures : a major bottleneck to algae-based fuels

Economic and technical problems related to the reduction of petroleum resources require the valorisation of renewable raw material Recently, microalgae emerged as promising alternative feedstock that represents an enormous biodiversity with multiple benefits exceeding the potential of conventional agricultural feedstock Thus, this comprehensive review article spots the light on one of the most interesting microalga Chlorella vulgaris It assembles the history and a thorough description of its ultrastructure and composition according to growth conditions The harvesting techniques are presented in relation to the novel algo-refinery concept, with their technological advancements and potential applications in the market

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Morphology, composition, production, processing and applications of Chlorella vulgaris: A review

https://repositorium.sdum.uminho.pt/bitstream/1822/22392/1/Artigo8.12_JAT.pdf

Mixotrophic cultivation of Chlorella vulgaris using industrial dairy waste as organic carbon source.

Microalgal hydrogen production – A review

https://repositorium.sdum.uminho.pt/bitstream/1822/24919/1/pp.pdf

Optimization of CO2 bio-mitigation by Chlorella vulgaris

Different methods for estimating starch in Chlorella vulgaris were compared with the view of establishing a procedure suitable for rapid and accurate determination of starch content in this microalgal species. A close agreement was observed between methods that use perchloric acid and enzymatic methods that use α-amylase and amyloglucosidase to hydrolyze the starch of microalgae grown under different nitrogen culture conditions. Starch values obtained by these methods were significantly higher than those estimated by using hydrochloric acid as solubilizing and hydrolyzing agent. The enzymatic method (EM1) proved to be the most rapid and precise method for microalgal starch quantification. Furthermore, the evaluation of resistant starch by enzymatic methods assayed in nitrogen-sufficient and nitrogen-starved cells showed that no formation of this type of starch occurred in microalgae, meaning that this should not interfere with starch content determinations.

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Starch determination in Chlorella vulgaris—a comparison between acid and enzymatic methods

Thisresearch workwas supported by theGrants SFRH/BPD/98694/ 2013 (Bruno Fernandes), SFRH/BD/110723/2015 (Rui Rodrigues), SFRH/BPD/81887/2011 (Ricardo Pereira) and SFRH/BD/52335/2013 (Pedro Geada) from Fundacao para a Ciencia e a Tecnologia (Portugal). Luis Loureiro is recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15) funded by the European Social Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. This study was also supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-FEDER-006684), Project UID/Multi/04423/2013, Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), FCT Strategic Project of UID/BIO/04469/2013 unit, by the project NOVELMAR (reference NORTE-01-0145-FEDER-000035), co-ﬁnanced by the North Portugal Regional Operational Programme (Norte 2020) under the National Strategic Reference Framework (NSRF), through the ERDF and by BioTecNorte operation (NORTE-01-0145-FEDER 000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte.

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Electrotechnologies applied to microalgal biotechnology Applications, techniques and future trends

https://repositorium.sdum.uminho.pt/bitstream/1822/72522/1/document_54374_1.pdf

Algal proteins: Production strategies and nutritional and functional properties.

Despite the initial interest, since the early 1950s, in microalgae as a source of biofuels to overcome the widespread negative impact on environment caused by fossil fuels, recent research studies turned the community's attention to high-added-value products from other biotechnological fields (e.g., food and feed, cosmetics, pharmaceutical, chemical). However, despite of the possible added-value, optimizing algal biomass cultivation arises as a permanent need at industrial scale to increase cost-effectiveness. Therefore, depending on the selected microalgae, many other features such as nutrition type, cultivation mode and strategies, cultivation system selection, and microalgal products' application must be considered. All these issues will be addressed in this chapter aiming at being an aid to tackle current drawbacks occurring during microalgal biomass cultivation.

Chapter 13 – Microalgal Biomass Cultivation

The combined effect of four abiotic factors on Microcystis aeruginosa growth and toxin production was assessed by culturing the cyanobacterium under different light intensities (10–190 μmol photons·m− 2·s− 1), CO2 concentrations (0–10% (v/v)), temperatures (15–40 °C), and pH values (6.5–9.5). Results indicate a significant influence caused by the synergistic effect of environmental factors over growth-related parameters and cyanobacteria toxicity. The combined use of low to medium light intensities (50–120 μmol photons·m− 2·s− 1) and CO2 concentration (1–6% v/v) led to higher cell concentrations, while specific growth rate and biomass productivity were favoured by medium to high light intensities (110–190 μmol photons·m− 2·s− 1), CO2 concentrations (4–9.5% v/v) and temperatures (29–39 °C). Regarding microcystin (MC) production, higher concentrations were obtained at low light intensities and low CO2 concentrations while approximately 2000-fold lower MC concentrations were achieved by simultaneous use of high values of light intensity, CO2 concentration and temperature.

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Pedro Geada

Papers

Starch determination in Chlorella vulgaris—a comparison between acid and enzymatic methods

Electrotechnologies applied to microalgal biotechnology Applications, techniques and future trends

Algal proteins: Production strategies and nutritional and functional properties.

Chapter 13 – Microalgal Biomass Cultivation

Assessment of synergistic interactions between environmental factors on Microcystis aeruginosa growth and microcystin production