Photosynthesis monitoring to optimize growth of microalgal mass cultures: application of chlorophyll fluorescence techniques

Malapascua, José Romel; Jerez, Celia G.; Sergejevová, Magda; Figueroa, Félix L.; Masojidek, J.

doi:10.3354/ab00597

Cited by 148 publications

(107 citation statements)

References 70 publications

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“…Chlorophyll a (Chl a) fluorescence measurement has become the standard noninvasive method to monitor the photosynthetic performance of microalgal mass cultures [21] and the physiological stress leading to lipid accumulation [130]. Although photosynthetic activity-the driving force of autotrophic growth-can also be monitored by measuring oxygen production and CO 2 uptake, fluorescence methods are faster and more sensitive.…”

Section: Photosynthetic Efficiency and Quantum Yieldmentioning

confidence: 99%

“…Although photosynthetic activity-the driving force of autotrophic growth-can also be monitored by measuring oxygen production and CO 2 uptake, fluorescence methods are faster and more sensitive. However, Chl a fluorescence measures only the photosynthetic rate and not respiratory rates, and thus must be supported by oxygen production measurement [21]. Direct measurement of the Chl a fluorescence yield has the advantage of directly assessing the performance of the photosynthetic apparatus as a composite variable that reflects any disturbances in the process and deviations from optimal conditions.…”

Section: Photosynthetic Efficiency and Quantum Yieldmentioning

confidence: 99%

“…Biological parameters, such as biomass concentration and composition and the presence of contamination, are usually measured offline using culture samples both in small-scale and large-scale PBRs. At present, continuous online measurements of biological parameters include measurement of optical density as a proxy for biomass concentration (laboratory-scale photobioreactors [17,50,51]) and the current photosynthetic activity in the culture with a pulse amplitude modulated (PAM) fluorometer in laboratory-and pilot-scale photobioreactors [21,52,53].…”

Section: Process Variables In Microalgal Cultivationsmentioning

confidence: 99%

“…The first method, providing the Chl a fluorescence induction curve (the Kautsky effect), can be performed only in an offline mode as it requires a dark-adapted culture. The PAM method can measure photosynthetic activity in situ and online using a PAM fluorometer [17,18,21,52,55,61,134], and the result is the photochemical quantum yield of photosynthesis (PQY, Y II , Φ PSII ), which characterizes the efficiency of excitation capture by open photosystem II reaction centers [19,61,135]. Measurement of photosynthetic activity by Chl a fluorescence should be used only in a relative sense, as in following changes in photosynthetic performance in the course of a cultivation, because estimation of absolute rates of photosynthesis in this way is subject to errors [131].…”

Section: Photosynthetic Efficiency and Quantum Yieldmentioning

confidence: 99%

“…Here, sensors function in a simple environment, the need for repeated calibration is not a concern, advanced methods and sensors can be tested without substantial risks, and comprehensive instrumentation for measurements in the gas, liquid, and biological phase is typical. Many examples of fully instrumented laboratory-scale PBRs can be found, equipped with sensors for light measurement, gas phase analysis (O 2 , CO 2 ), temperature, pH, dissolved O 2 and CO 2 , turbidity, optical density, and chlorophyll fluorescence [17][18][19][20][21]. Some of these laboratory-scale PBRs have been developed and instrumented in research institutions (e.g., the short light-path (SLP) panel photobioreactor [22], or the Midiplate flat panel reactor at the Karlsruhe Institute of Technology (KIT) [20,23]) but many companies marketing standard bioreactors also manufacture photobioreactors (e.g., Infors) while others specialize in the photobioreactor field (PSI [17], bbi-biotech, Subitec, to name only a few European manufacturers).…”

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confidence: 99%

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Monitoring of Microalgal Processes

Havlík

Scheper

Reardon

2015

Microalgae Biotechnology

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Process monitoring, which can be defined as the measurement of process variables with the smallest possible delay, is combined with process models to form the basis for successful process control. Minimizing the measurement delay leads inevitably to employing online, in situ sensors where possible, preferably using noninvasive measurement methods with stable, low-cost sensors. Microalgal processes have similarities to traditional bioprocesses but also have unique monitoring requirements. In general, variables to be monitored in microalgal processes can be categorized as physical, chemical, and biological, and they are measured in gaseous, liquid, and solid (biological) phases. Physical and chemical process variables can be usually monitored online using standard industrial sensors. The monitoring of biological process variables, however, relies mostly on sensors developed and validated using laboratory-scale systems or uses offline methods because of difficulties in developing suitable online sensors. Here, we review current technologies for online, in situ monitoring of all types of process parameters of microalgal cultivations, with a focus on monitoring of biological parameters. We discuss newly introduced methods for measuring biological parameters that could be possibly adapted for routine online use, should be preferably noninvasive, and are based on approaches that have been proven in other bioprocesses. New sensor types for measuring physicochemical parameters using optical methods or ion-specific field effect transistor (ISFET) sensors are also discussed. Reviewed methods with online implementation or online potential include measurement of irradiance, biomass concentration by optical density and image analysis, cell count, chlorophyll fluorescence, growth rate, lipid concentration by infrared spectrophotometry, dielectric scattering, and nuclear magnetic resonance. Future perspectives are discussed, especially in the field of image analysis using in situ microscopy, infrared spectrophotometry, and software sensor systems.

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Section: Photosynthetic Efficiency and Quantum Yieldmentioning

confidence: 99%

Section: Photosynthetic Efficiency and Quantum Yieldmentioning

confidence: 99%

Section: Process Variables In Microalgal Cultivationsmentioning

confidence: 99%

Section: Photosynthetic Efficiency and Quantum Yieldmentioning

confidence: 99%

mentioning

confidence: 99%

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Monitoring of Microalgal Processes

Havlík

Scheper

Reardon

2015

Microalgae Biotechnology

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In situ monitoring of chlorophyll a fluorescence in Nannochloropsis oceanica cultures to assess photochemical changes and the onset of lipid accumulation during nitrogen deprivation

Carneiro

Zittelli

Cicchi

et al. 2021

Biotech & Bioengineering

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In situ chlorophyll a fluorescence measurements were applied to monitor changes in the photochemical variables of Nannochloropsis oceanica cultures under nitrogendeplete and nitrogen-replete (control) conditions. In addition, growth, lipid, fatty acid, and pigment contents were also followed. In the control culture, growth was promoted along with pigment content, electron transport rate (ETR), and polyunsaturated fatty acids, while total lipid content and fatty acid saturation level diminished. Under nitrogen-deplete conditions, the culture showed a higher deepoxidation state of the xanthophyll cycle pigments. Fast transients revealed a poor processing efficiency for electron transfer beyond Q A , which was in line with the low ETR due to nitrogen depletion. Lipid content and the de-epoxidation state were the first biochemical variables triggered by the change in nutrient status, which coincided with a 20% drop in the in situ effective quantum yield of PSII (ΔF'/F m '), and a raise in the V j measurements. A good correlation was found between the changes in ΔF'/F m ' and lipid content (r = −0.96, p < 0.01). The results confirm the reliability and applicability of in situ fluorescence measurements to monitor lipid induction in N. oceanica.

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Modification of the electrokinetic motion of microalgae through light illumination for viability assessment

Li,

Jiang,

et al. 2024

Electrophoresis

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The viability detection of microalgae with the electrokinetic (EK) technique shows vast applications in the biology and maritime industry. However, due to the slight variations in the EK properties between alive and dead microalgae cells, the accuracy and practicability of this technique is limited. In this paper, the light illumination pretreatment was conducted to modify the EK velocity of microalgae for enhancing the EK difference. The effects of the illumination time and light color on the EK velocities of Chlorella vulgaris and Isochrysis galbana were systematically measured, and the EK differences between alive and dead cells were calculated and compared. The results indicate that under light illumination, the photosynthesis of the alive cells leads to the amplification of the zeta potential, leading toward increase in the EK difference along with the illumination time. By using light with different color spectra to treat the microalgae, it was found that the EK difference changes with the light color according to the following order: white light > red light > blue light > green light. The difference in EK potential with exposure to white light treatment surpasses over 10‐fold in comparison to those without such treatment. The light pretreatment technique, as illustrated in this study, offers an advantageous strategy to enhance the EK difference between living and dead cells, proving beneficial in the field of microalgae biotechnology.

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Photosynthesis monitoring to optimize growth of microalgal mass cultures: application of chlorophyll fluorescence techniques

Cited by 148 publications

References 70 publications

Monitoring of Microalgal Processes

Monitoring of Microalgal Processes

In situ monitoring of chlorophyll a fluorescence in Nannochloropsis oceanica cultures to assess photochemical changes and the onset of lipid accumulation during nitrogen deprivation

Modification of the electrokinetic motion of microalgae through light illumination for viability assessment

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