Algal Physiology and Large-Scale Outdoor Cultures of Microalgae

Borowitzka, Michael A.

doi:10.1007/978-3-319-24945-2_23

Cited by 84 publications

(65 citation statements)

References 593 publications

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“…An increase in temperatures limits the growth performance of microalgae in field conditions, particularly in photobioreactors (PBRs) [ 16 ]. The water temperatures in tropical and subtropical regions, particularly in the closed PBRs, frequently surpass 40–45 °C without temperature control.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a heat-tolerant Chlorella sp. GD mutant with enhanced photosynthetic CO2 fixation efficiency and its implication as lactic acid fermentation feedstock

Lee

Tseng

Cheng

et al. 2017

Biotechnol Biofuels

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Background: Fermentative production of lactic acid from algae-based carbohydrates devoid of lignin has attracted great attention for its potential as a suitable alternative substrate compared to lignocellulosic biomass. Results:A Chlorella sp. GD mutant with enhanced thermo-tolerance was obtained by mutagenesis using N-methyl-N′-nitro-N-nitrosoguanidine to overcome outdoor high-temperature inhibition and it was used as a feedstock for fermentative lactic acid production. The indoor experiments showed that biomass, reducing sugar content, photosynthetic O 2 evolution rate, photosystem II activity (F v /F m and F v ′/F m ′), and chlorophyll content increased as temperature, light intensity, and CO 2 concentration increased. The mutant showed similar DIC affinity and initial slope of photosynthetic light response curve (α) as that of the wild type but had higher dissolved inorganic carbon (DIC) utilization capacity and maximum photosynthesis rate (P max ). Moreover, the PSII activity (F v ′/F m ′) in the mutant remained normal without acclimation process after being transferred to photobioreactor. This suggests that efficient utilization of incident high light and enhanced carbon fixation with its subsequent flux to carbohydrates accumulation in the mutant contributes to higher sugar and biomass productivity under enriched CO 2 condition. The mutant was cultured outdoors in a photobioreactor with 6% CO 2 aeration in hot summer season in southern Taiwan. The harvested biomass was subjected to separate hydrolysis and fermentation (SHF) for lactic acid production with carbohydrate concentration equivalent to 20 g/L glucose using the lactic acid-producing bacterium Lactobacillus plantarum 23. The conversion rate and yield of lactic acid were 80% and 0.43 g/g Chlorella biomass, respectively. Conclusions: These results demonstrated that the thermo-tolerant Chlorella mutant with high photosynthetic efficiency and biomass productivity under hot outdoor condition is an efficient fermentative feedstock for large-scale lactic acid production.

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Section: Introductionmentioning

confidence: 99%

Characterization of a heat-tolerant Chlorella sp. GD mutant with enhanced photosynthetic CO2 fixation efficiency and its implication as lactic acid fermentation feedstock

Lee

Tseng

Cheng

et al. 2017

Biotechnol Biofuels

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“…Key environmental factors such as light intensity, temperature, salinity, and nutrient composition, regulate algal growth in large-scale facilities (Borowitzka 2016;Nur and Buma 2018). Simultaneously, apart from affecting growth, irradiance level might also affect the fucoxanthin content of P. tricornutum since it is a light harvesting pigment (Gómez-Loredo et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Environmental and nutrient conditions influence fucoxanthin productivity of the marine diatom Phaeodactylum tricornutum grown on palm oil mill effluent

et al. 2018

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Palm oil mill effluent (POME) is a type of wastewater posing large problems when discharged in the environment. Yet, due to its high nutrient content, POME may offer opportunities for algal growth and subsequent harvesting of high-value products. The marine diatom Phaeodactylum tricornutum is a potential feedstock diatom for bioactive compounds such as the carotenoid fucoxanthin, which has been shown to have pharmaceutical applications. The aim of this paper was to evaluate the growth and fucoxanthin productivity of P. tricornutum grown on POME, as a function of light intensity, temperature, salinity, and nutrient enrichment. High-saturating irradiance (300 μmol photons m −2 s −1) levels at 25°C showed highest growth rates but decreased the fucoxanthin productivity of P. tricornutum. Box-Behnken response surface methodology revealed that the optimum fucoxanthin productivity was influenced by temperature, salinity, and the addition of urea. Nutrient enrichment by phosphorus did not enhance cell density and fucoxanthin productivity, while urea addition was found to stimulate both. We conclude that POME wastewater, supplemented with urea, can be considered as the potential medium for P. tricornutum to replace commercial nutrients while producing high amounts of fucoxanthin.

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“…These will be discussed in the following sections. Borowitzka (2016) has noted that "the quantity and quality of light available to the algae are recognised as the single main factors limiting the productivity of algal mass cultures outdoors." However, increasing photosynthetic e ciency is not so simple as merely exposing the cells to more light.…”

Section: Photosynthesis and Lipid Biosynthesismentioning

confidence: 99%

“…a "flash") followed by a period of darkness. This process has demonstrated increased productivity in algal cells (see Borowitzka, 2016, and references therein).…”

Section: Photosynthesis and Lipid Biosynthesismentioning

confidence: 99%

Identifying the dominant physical processes for mixing in full-scale raceway tanks

2018

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Biodiesels from microalgae are a promising alternative to fossil fuels with a number of unique benefits over other alternative fuel sources. However, to date, their viability in the fuels market remains infeasible due in part to a number of ine ciencies in the cultivation process. This has led to a growing interest in the hydrodynamics of open raceway tank (RWT) reactors, and cultivating conditions that are favorable to algae growth. In particular, two impediments require attention: the lack of vertical mixing in the straight portions of the reactor, and the need for e cient introduction of atmospheric carbon into the growth medium. It is proposed that the promotion of cellular, secondary currents by introduction of longitudinal ridges along the bed of the reactor can both promote vertical mixing and enhance gas transfer across the free surface of the growth medium. Experiments are performed in a full-scale open RWT at the University of Illinois, Urbana-Champaign, Ecohydraulics and Ecomorphodynamics Laboratory (EEL), in which the bed of the RWT is modified with longitudinal ridges of two di↵erent sizes, triangular and semi-circular cross-sections, and variable spacing.The 3-dimensional velocity components are monitored at significant locations in the reactor by means of acoustic doppler velocimetry (ADV) and surface particle image velocimetry (sPIV), and the gas transfer across the free-surface is measured by re-aeration curves of dissolved oxygen (DO). It is found that the cellular, secondary cells can be visualized in the velocity data after the introduction of longitudinal ridges. However, the impacts at the free surface are limited and consequently so is the gas transfer. A range of flow structures are observed that impact the relative significance of these cellular currents, including: vortex shedding from bend vanes, secondary currents of Prandtl's first kind induced by the ii bends, paddlewheel pulsation, and boundary layer development. These structures are found to overwhelm the presence of the cellular currents, and indicate that flows in the straight portions of the RWT reactor are a complex composite of boundary layer flow, secondary currents, resonance structures, energy input conditions, and shear flows. If cellular, secondary currents are to be used to promote the ideal algae growth conditions, further developments on this method will be required to overwhelm or work cooperatively with the dominant bend-induced dynamics.iii To Jarah.

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Algal Physiology and Large-Scale Outdoor Cultures of Microalgae

Cited by 84 publications

References 593 publications

Characterization of a heat-tolerant Chlorella sp. GD mutant with enhanced photosynthetic CO2 fixation efficiency and its implication as lactic acid fermentation feedstock

Characterization of a heat-tolerant Chlorella sp. GD mutant with enhanced photosynthetic CO2 fixation efficiency and its implication as lactic acid fermentation feedstock

Environmental and nutrient conditions influence fucoxanthin productivity of the marine diatom Phaeodactylum tricornutum grown on palm oil mill effluent

Identifying the dominant physical processes for mixing in full-scale raceway tanks

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