Real-Time Monitoring of Microalgal Biomass in Pilot-Scale Photobioreactors Using Nephelometry

Thoré, Eli S.J.; Schoeters, Floris; Spit, Jornt; Miert, Sabine Van

doi:10.3390/pr9091530

Cited by 10 publications

(9 citation statements)

References 33 publications

(41 reference statements)

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“…It is possible to use a continuous turbidity measurement in combination with the correlation between turbidity and dry weight to track the dry weight evolution ( Thoré et al, 2021 ). Our results, however, also indicate that caution is needed when interpreting and linking turbidity measurements with the dry weight of the microalga cultivated.…”

Section: Resultsmentioning

confidence: 99%

“…The algal growth in the bioreactor was monitored online every 30 min with a turbidity meter. The measured turbidity was correlated with a dry weight value based on a correlation described previously ( Thoré et al, 2021 ). In addition to the continuous monitoring by turbidity, the dry weight (g L −1 ) was determined at the start (C s ) and end (C e ) of each batch and at random moments during the growth periods.…”

Section: Methodsmentioning

confidence: 99%

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Pilot-Scale Cultivation of the Snow Alga Chloromonas typhlos in a Photobioreactor

Schoeters

Spit

Azizah

et al. 2022

Front. Bioeng. Biotechnol.

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The most studied and cultivated microalgae have a temperature optimum between 20 and 35°C. This temperature range hampers sustainable microalgae growth in countries with colder periods. To overcome this problem, psychrotolerant microalgae, such as the snow alga Chloromonas typhlos, can be cultivated during these colder periods. However, most of the research work has been carried out in the laboratory. The step between laboratory-scale and large-scale cultivation is difficult, making pilot-scale tests crucial to gather more information. Here, we presented a successful pilot-scale growth test of C. typhlos. Seven batch mode growth periods were compared during two longer growth tests in a photobioreactor of 350 L. We demonstrated the potential of this alga to be cultivated at colder ambient temperatures. The tests were performed during winter and springtime to compare ambient temperature and sunlight influences. The growth and CO2 usage were continuously monitored to calculate the productivity and CO2 fixation efficiency. A maximum dry weight of 1.082 g L−1 was achieved while a maximum growth rate and maximum daily volumetric and areal productivities of 0.105 d−1, 0.110 g L−1 d−1, and 2.746 g m−2 d−1, respectively, were measured. Future tests to optimize the cultivation of C. typhlos and production of astaxanthin, for example, will be crucial to explore the potential of biomass production of C. typhlos on a commercial scale.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Pilot-Scale Cultivation of the Snow Alga Chloromonas typhlos in a Photobioreactor

Schoeters

Spit

Azizah

et al. 2022

Front. Bioeng. Biotechnol.

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“…Fig. 3; Thoré et al, 2021). Of these, we have randomly selected two independent mutants, called pht4-7#7 and #9 for further detailed analyses.…”

Section: Crpht4-7 Is Required For Normal Growth Especially At High Lightmentioning

confidence: 99%

The chloroplastic phosphate transporter CrPHT4-7 supports phosphate homeostasis and photosynthesis in Chlamydomonas

Tóth,

Kuntam,

Ferenczi

et al. 2023

Preprint

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In eukaryotic cells, phosphorus is assimilated and utilized primarily as phosphate (Pi). Pi homeostasis is mediated by transporters that have not yet been adequately characterized in green algae. This study reports on CrPHT4-7 fromChlamydomonas reinhardtii, a member of the PHT4 transporter family, which exhibits remarkable similarity to AtPHT4;4 fromArabidopsis thaliana, a chloroplastic ascorbate transporter. Using fluorescent protein tagging we show that CrPHT4-7 resides in the chloroplast envelope membrane.Crpht4-7mutants, generated by the CRISPR/Cas12a-mediated single-strand templated repair, show retarded growth especially in high light, enhanced sensitivity to phosphorus limitation, reduced ATP level, strong ascorbate accumulation and diminished non-photochemical quenching in high light. Conversely, CrPHT4-7 overexpressing lines exhibit enhanced biomass accumulation under high light conditions in comparison with the wild-type strain. Expressing CrPHT4-7 in a yeast strain lacking Pi transporters substantially recovered its slow growth phenotype demonstrating that it transports Pi. Even though CrPHT4-7 shows a high degree of similarity to AtPHT4;4, it does not display any significant ascorbate transport activity in yeast or intact algal cells. Thus, the results demonstrate that CrPHT4-7 functions as a chloroplastic Pi transporter essential for maintaining Pi homeostasis and photosynthesis inChlamydomonas reinhardtii.One-sentence summaryWe demonstrate that the CrPHT4-7 transporter ofChlamydomonas reinhardtiiis located in the chloroplast envelope membrane and contributes to maintaining phosphate homeostasis and photosynthesis.

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“…(2) On-line implementation possible. Vout/OD: R 2 = 0.95 [16] NTU/DWC: R 2 = 0.88-0.93 [18] OD/DWC: R 2 = 0.88-0.92 [18] OD/DWC: R 2 = 0.99 [20] Biomass Color analysis (RGB) OD/DWC: R 2 = 0.998 [26] PBR bypass [26] [26]…”

Section: Quantum Yield (Photosynthetic Efficiency) Contaminationmentioning

confidence: 99%

“…Thoré et al [18] monitored BC of three species (Chloromonas typhlos, Microchloropsis gaditana and Porphyridium purpureum) in closed, pilot-scale PBRs on-line and in real time using a flow-through nephelometer and related nephelometric turbidity (in NTU) to DWC and optical density at four wavelengths ranging from 435 to 720 nm. The resulting relationships between turbidity (NTU) and DWC and between DWC and OD 720 were nonlinear, with R 2 = 0.88-0.93 and R 2 = 0.88-0.92, respectively, differing between species.…”

Section: Monitoring Bc Using Direct Sensors Without Complex Signal Evaluationmentioning

confidence: 99%

On-Line Monitoring of Biological Parameters in Microalgal Bioprocesses Using Optical Methods

et al. 2022

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Microalgae are promising sources of fuels and other chemicals. To operate microalgal cultivations efficiently, process control based on monitoring of process variables is needed. On-line sensing has important advantages over off-line and other analytical and sensing methods in minimizing the measurement delay. Consequently, on-line, in-situ sensors are preferred. In this respect, optical sensors occupy a central position since they are versatile and readily implemented in an on-line format. In biotechnological processes, measurements are performed in three phases (gaseous, liquid and solid (biomass)), and monitored process variables can be classified as physical, chemical and biological. On-line sensing technologies that rely on standard industrial sensors employed in chemical processes are already well-established for monitoring the physical and chemical environment of an algal cultivation. In contrast, on-line sensors for the process variables of the biological phase, whether biomass, intracellular or extracellular products, or the physiological state of living cells, are at an earlier developmental stage and are the focus of this review. On-line monitoring of biological process variables is much more difficult and sometimes impossible and must rely on indirect measurement and extensive data processing. In contrast to other recent reviews, this review concentrates on current methods and technologies for monitoring of biological parameters in microalgal cultivations that are suitable for the on-line and in-situ implementation. These parameters include cell concentration, chlorophyll content, irradiance, and lipid and pigment concentration and are measured using NMR, IR spectrophotometry, dielectric scattering, and multispectral methods. An important part of the review is the computer-aided monitoring of microalgal cultivations in the form of software sensors, the use of multi-parameter measurements in mathematical process models, fuzzy logic and artificial neural networks. In the future, software sensors will play an increasing role in the real-time estimation of biological variables because of their flexibility and extendibility.

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Real-Time Monitoring of Microalgal Biomass in Pilot-Scale Photobioreactors Using Nephelometry

Cited by 10 publications

References 33 publications

Pilot-Scale Cultivation of the Snow Alga Chloromonas typhlos in a Photobioreactor

Pilot-Scale Cultivation of the Snow Alga Chloromonas typhlos in a Photobioreactor

The chloroplastic phosphate transporter CrPHT4-7 supports phosphate homeostasis and photosynthesis in Chlamydomonas

On-Line Monitoring of Biological Parameters in Microalgal Bioprocesses Using Optical Methods

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