Effect of hydrodynamic stress on <i>dunaliella</i> growth

Silva, Humberto J.; Cortifas, Teresa; Ertola, R. J.

doi:10.1002/jctb.280400105

Cited by 66 publications

(14 citation statements)

References 16 publications

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“…Disc-stack centrifuges are ideally suited for separating particles of the size (3 -30 µm) and concentration (0.02 -0.05%) [20] typical of algal cells found in commercial growth systems [27,29]. However, they shear and lyse the Dunaliella cells during the separation cycle because of the combination of high g-forces (11,000 -15,000 g) and hydrodynamic stresses [27,[30][31][32]. For the harvesting of cell biomass enriched in β-carotene this has not been a problem: β-carotene accumulates as droplets in the periphery of chloroplasts and remains within the algal biomass during separation: it is readily recoverable.…”

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confidence: 99%

Effects of centrifugal stress on cell disruption and glycerol leakage from Dunaliella salina

Milledge

Abubakar

et al. 2015

Microalgae Biotechnology

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Dunaliella salina accumulates large amounts of intracellular glycerol in response to the increases in salt concentration, thus is a potential source for producing fuel grade glycerol as an alternative to biodiesel-derived crude glycerol. D. salina lacks a cell wall; therefore the mode of harvesting Dunaliella cells is critical to avoid cell disruption caused by extreme engineering conditions. This study explored cell disruption and glycerol leakage of D. salina under various centrifugal stresses during cell harvesting. Results show a centrifugal g-force lower than 5000 g caused little cell disruption, while a g-force higher than 9000 g led to ~40% loss of the intact cells and glycerol yields from the recovered algal pellets. Theoretical calculations of the centrifugal stresses that could rupture Dunaliella cells were in agreement with the experimental results, indicating optimisation of centrifugation conditions is important for recovering intact cells of D. salina enriched in glycerol.

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confidence: 99%

Effects of centrifugal stress on cell disruption and glycerol leakage from Dunaliella salina

Milledge

Abubakar

et al. 2015

Microalgae Biotechnology

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“…cultures in continuous mode at different irradiances on the reactors' surface value limiting the existence of stress damage differs depending on the strain and the power supply system. In P. tricornutum, the yield of the cultures was reduced at aeration rates above 1.3 v/v/min (Sánchez-Mirón et al 2003), whereas in P. cruentum the yield reduces at gas flow rates above 2 v/v/min (García-Camacho et al 2000), and in Dunaliella salina it reduces at aerations above 1.0 v/v/min (Silva et al 1987). In P. tricornutum, the yield of the cultures was reduced at shear rates higher than 30 1/s (Brindley et al 2004), whereas in this report a limit value of shear rate of 60 1/s has been determined for Anabaena sp.…”

Section: Discussionmentioning

confidence: 93%

Utilization of Anabaena sp. in CO2 removal processes

Fernández

González-López

Fernández

et al. 2012

Appl Microbiol Biotechnol

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This paper focuses on modelling the growth rate and exopolysaccharides production of Anabaena sp. ATCC 33047, to be used in carbon dioxide removal and biofuels production. For this, the influence of dilution rate, irradiance and aeration rate on the biomass and exopolysaccharides productivity, as well as on the CO(2) fixation rate, have been studied. The productivity of the cultures was maximum at the highest irradiance and dilution rate assayed, resulting to 0.5 g(bio) l(-1) day(-1) and 0.2 g(eps) l(-1) day(-1), and the CO(2) fixation rate measured was 1.0 gCO(2) l(-1) day(-1). The results showed that although Anabaena sp. was partially photo-inhibited at irradiances higher than 1,300 μE m(-2) s(-1), its growth rate increases hyperbolically with the average irradiance inside the culture, and so does the specific exopolysaccharides production rate. The latter, on the other hand, decreases under high external irradiances, indicating that the exopolysaccharides metabolism hindered by photo-damage. Mathematical models that consider these phenomena have been proposed. Regarding aeration, the yield of the cultures decreased at rates over 0.5 v/v/min or when shear rates were higher than 60 s(-1), demonstrating the existence of thus existence of stress damage by aeration. The behaviour of the cultures has been verified outdoors in a pilot-scale airlift tubular photobioreactor. From this study it is concluded that Anabaena sp. is highly recommended to transform CO(2) into valuable products as has been proved capable of metabolizing carbon dioxide at rates of 1.2 gCO(2) l(-1) day(-1) outdoors. The adequacy of the proposed equations is demonstrated, resulting to a useful tool in the design and operation of photobioreactors using this strain.

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“…Dunaliella, Hematococcus, Porphyridium). Many studies have also been carried out on the effects of culture agitation, airflow rate, bubble dimensions and gas entrance velocity at the sparger [11,[103][104][105]. Tubular photobioreactors have been the most studied systems during the twenty-year Italian experience in the field.…”

Section: Discussionmentioning

confidence: 99%

Closed Photobioreactor Assessments to Grow, Intensively, Light Dependent Microorganisms: A Twenty-Year Italian Outdoor Investigation

Carlozzi

2008

TOBIOTJ

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Twenty years of Italian outdoor investigations on closed photobioreactors are discussed in this review. Many photobioreactor designs have been projected; some have been built, tested and patented. The Italian research approach from tubular (single tube and traditional loop) to flat and column and again to tubular photobioreactors (coil and loops) has improved microalgal yield. It increased from 25.0 gm -2 d -1 in 1986 (using a traditional loop set down on the ground) to 47.7 gm -2 d -1 in 2003, when results of a new tubular undulating row photobioreactor (TURP) were reported. This very high TURP productivity was attributed to a light dilution growth-strategy using Arthrospira platensis; the photic ratio (R f ) ranged from 3 to 6.

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Effect of hydrodynamic stress on dunaliella growth

Cited by 66 publications

References 16 publications

Effects of centrifugal stress on cell disruption and glycerol leakage from Dunaliella salina

Effects of centrifugal stress on cell disruption and glycerol leakage from Dunaliella salina

Utilization of Anabaena sp. in CO2 removal processes

Closed Photobioreactor Assessments to Grow, Intensively, Light Dependent Microorganisms: A Twenty-Year Italian Outdoor Investigation

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