Limnospira indica PCC8005 growth in photobioreactor: model and simulation of the ISS and ground experiments

Probably not a substantial claim: may not pass S3 (load-bearing).

The two-flux radiative-transfer model used here has already been shown to be efficient in several studies.

“following the two-flux model analytical solution of the dimensionless Eq. 1, (Cornet and Dussap, 2009) that has already been proved efficient in several studies (Cogne et al. 2005, Ifrim et al. 2014, Pruvost et al., 2016)”

• cites Cornet and Dussap, 2009 sourceSupported
• cites Cogne et al. 2005 sourceNot checked — no full text of the source
• cites Ifrim et al. 2014 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

In spaceflight, radiation effects must be added to microgravity effects and are more important than the microgravity effects.

“Moreover, in space flight conditions, the radiation effects must be added to microgravity effects being even more important than the microgravity effects (Mastroleo et al., 2009).”

• cites Mastroleo et al., 2009 sourcePartly supported

  The Conclusion (p. 15) identifies both microgravity and ionizing radiation as spaceflight-related factors. But the Discussion (p. 13) says radiation had a more pronounced effect only in the BASE-A simulation; the opposite was observed in MESSAGE 2. The paper therefore does not support the unqualified claim that radiation effects are more important than microgravity effects in spaceflight. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

May combine two claims.

Under these conditions, the exopolysaccharide mass fraction in total biomass remained below 35%, which reduces cell aggregation and biofilm formation.

“In these conditions the mass fraction of exopolysaccharide in the total biomass was always maintained below 35%, reducing the problematic of cell aggregation and biofilm formation (Cornet et al 1998(Cornet et al , 2009)).”

• cites Cornet et al 1998 sourceNot checked — no full text of the source
• cites Cornet et al 2009 sourceCould not verify

  The Materials and Methods (p. 7) describe measuring dry biomass, and the Discussion (p. 28) addresses maximum biomass productivity. Neither passage addresses exopolysaccharide as a fraction of biomass or its effect on aggregation and biofilm formation; searches for those terms and the 35% threshold found no supporting passage in our copy. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

May combine two claims.

This confirms the predictability of the model, which was already applied for various ground photobioreactors.

“This confirms the predictability of the model, which was already applied for various ground photobioreactors (Cogne et al., 2003 b , Cornet et al., 2009, Ifrim et al., 2014, Dauchet et al., 2016).”

• cites Cogne et al., 2003 b sourceNot checked — no full text of the source
• cites Cornet et al., 2009 sourceSupported
• cites Ifrim et al., 2014 sourceNot checked — no full text of the source

May combine two claims.

Reactor A4 showed no measurable biomass production in the start-up first batch; growth began at the end of batch 2 with a low-pressure increase profile in batches 3 and 4, similar to A1-batch1 but with a crushed shape.

“Reactor A4 showed no measurable biomass production for the start up first batch.The growth started at the end of batch 2 with a low-pressure increase profile in the last 2 batches (number 3 and 4), which looks like the pressure profile of reactor A1-batch1 but with a crushed shape.”

May combine two claims.

In the current study, pH was not controlled, which led to a pH increase above 10 in the culture medium and to a potential carbon limitation.

“For the current study, pH was not controlled leading to pH increase above 10 in the culture medium and to a potential C limitation.”

• AssumptionRests on an assumption: The CO2 needed for growth is obtained by dehydration of bicarbonate inside the cell, a reaction that releases hydroxyl ions and raises pH in the pH-uncontrolled micro photobioreactor.

May combine two claims.

Reactor A1 had a lower pressure increase than expected in batches 1, 2 and 3, but recovered the expected pressure profile at the end of batch 3 and throughout batch 4.

“Reactor A1 had a lower pressure increase than expected in batch 1, 2 and 3, but suddenly recovered the expected pressure profile at the end of batch 3 and for the entire batch 4.”

May combine two claims.

Across the 32 batches, 3 gave the expected oxygen production rate of 0.33 mmol O2/L/h, 7 gave 0.23 ± 0.03 mmol O2/L/h, 6 gave 0.1 ± 0.03 mmol O2/L/h, and 16 failed.

“Over the 32 batches, 3 gave the expected oxygen production rate of 0.33 mmol O2.L -1 .h-1 and 7 a production rate of 0.23 +-0.03 mmol O2.L -1 .h-1 (Table 1).For 6 batches the oxygen production rate calculated was 0.1 +/-0.03mmol O2.L -1 .h-1 .16 batches have failed”

Classified as probably not a substantial claim.

The GM3 reactor was operated with liquid mixing only via the external liquid loop at 1 mL/min.

“GM3 reactor was then ran with mixing of the liquid compartment only by the way of the external liquid loop (1 mL.min - 1 )”

May combine two claims.

The GM4 reactor and the B4 ISS reactor showed a sudden decrease in biomass and oxygen production at the end of batch 1, and recovery occurred only in batch 4.

“GM4 reactor had presented no technical failures, but like for the B4 ISS reactor at the end of the batch 1, the biomass and oxygen production suddenly decreased, and could only be recovered in batch 4.”

May combine two claims.

Normal stirring was recovered for ISS A1 batch 4, indicating that the stirrer had recovered normal functioning.

“A normal stirring has been recovered for ISS A1 batch 4 indicating that the stirrer has recovered a normal functioning”

May combine two claims.

A1 batches 1-3 had calculated oxygen yields around 0.5 gO2/gX, which were too low compared with the stoichiometric theoretical value.

“The values in the order of 0.5 gO2.gX -1 for A1-batches 1-3 were too low when compared to stoichiometric theoretical value”

May combine two claims.

For reactor B4, growth stopped after 290 h and biomass decay was then observed.

“For reactor B4, the growth stopped after 290h, and biomass decay was then observed.”

May combine two claims.

Reactor B1 never started, showing no biomass growth and no pressure increase, and was stopped after 21 days.

“Reactor B1 had never start (no biomass growth and no pressure increase) and was stopped after 21 days.”

May combine two claims.

The GM3 reactor had a stirring failure that was identified by visual inspection and confirmed after dismantling the reactor.

“A stirring failure was identified when visually inspecting the reactor that has been confirmed after dismantling the reactor after the experiment.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Several operational issues also occurred during the ground experiments.

“Several issues when running occurred also for ground experiments.”

May combine two claims.

On ground (GM1-b4, GM3-b2-b3), such functioning was characteristic of a magnetic stirrer dysfunction that degraded O2 transfer from liquid to gas and led to high O2 gas partial pressure in the liquid phase.

“It has been observed on-ground (GM1-b4, GM3-b2-b3) that such a functioning was characteristic of a dysfunction of the magnetic stirrer leading to degraded O2 transfer from the liquid phase to the gas phase leading to a high O2 gas partial pressure into the liquid phase.”

May combine two claims.

In the first batch, only reactor B4 produced the expected biomass and pressure profile, with pressure rising to the relief set point of 1.25 bar.

“For the first batch (culture start up) only the reactor B4 gave the expected biomass production and pressure profile with a pressure increase up to the relieve set point of 1.25 bar.”

May combine two claims.

It was calculated that the growth stop near 300 h occurs at pH 11.5, consistent with Pandey et al. (2010), who observed a 50% decrease in pigments at pH 10 and 11 and no growth at pH 12 in flask cultures.

“It has been calculated that the growth stop near 300h happens for a pH of 11.5, what was consistent with Pandey et al. (2010) who has observed a 50% decrease in pigments at pH 10 and 11, and no growth at pH 12 in flask cultures.”

• cites Pandey et al. (2010)Not checked — no full text of the source

May combine two claims.

For the ISS reactor, the limiting effect of bicarbonate availability at high pH was a bit lower than on ground, so the culture was maintained only in light-limited conditions until the pH threshold was observed.

“For ISS reactor, the limiting effect of bicarbonate availability at high pH was a bit lower than on ground, so that the culture was maintained only in light-limited conditions until the pH threshold was observed.”

May combine two claims.

The Arthrospira-B experiment was successfully run, and relevant results were obtained from online measurement of the oxygen production rate by Limnospira Indica PCC8005 in a micro photobioreactor operated in microgravity.

“The Arthrospira-B experiment was successfully run; relevant results have been obtained from online measurement of the oxygen production rate by Limnospira Indica PCC8005 in a micro Photobioreactor operated in microgravity.”

May combine two claims.

The remotely activated automated inoculation and reactor start-up failed for one reactor in space, but the procedure was successful for the three other space reactors and all ground reactors.

“The remotely activated automated inoculation and reactor start-up failed for one reactor in space, but the procedure was successful for the 3 other space reactors, and all ground reactors.”

May combine two claims.

The model fits both ground and microgravity experiments except when high pH conditions above 11 were reached.

“The model also fits both on ground and microgravity experiments except when high pH conditions (above 11) were reached.”

May combine two claims.

The model was further tuned by considering a 5 mL gas bubble in the liquid phase, resulting in a good fit of the experimental cumulative pressure with the model.

“the model was further tuned (Figure 11) by considering a 5 mL gas bubble into the liquid phase resulting into a good fit of the experimental cumulative pressure with the model.”

May combine two claims.

The space bioreactor compatible with the Biolab facility on ISS could not account for a pH sensor or regulation, so the process pH was uncontrolled and led to a steep pH increase when bicarbonate was consumed.

“The space bioreactor compatible with Biolab facility on ISS could not account for a pH sensor or regulation, so that pH of the process was uncontrolled, leading to a steep pH increase when bicarbonate was consumed.”

May combine two claims.

B4-b1 showed the same trend as the GM3-b11 reactor, and the tuned model can be used to represent the ISS reactor.

“B4-b1 showed the same trend as the GM3-b11 reactor and again, the tuned model can be used to represent the ISS reactor (Figure 12).”

May combine two claims.

There were technical difficulties with the stirrer and gas pressure measurement, leading to a non-perfectly mixed liquid phase for which the current model was not completely applicable.

“There were some technical difficulties with the stirrer and gas pressure measurement, leading to a non-perfectly mixed liquid phase, for which the current model was not completely applicable.”

May combine two claims.

Four ground reactors and four ISS reactors were run in parallel as independent biological replicates.

“Four reactors on ground and four reactors on-board ISS were used in parallel to test the behaviour of four independent bacterial cultures (4 independent biological replicates).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The experiment was designed so that all four reactors were operated under the same conditions, and the same results were expected.

“The experiment was designed in order that all four reactors were operated in same conditions, so that the same results were expected.”

May combine two claims.

The low oxygen yields in A1 batches 1-3 suggest either a pressure problem such as gas leakage or pressure sensor malfunction, or biomass overestimation.

“suggesting either a pressure problem (such as gas leakage or pressure sensor malfunction) or a biomass overestimation.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The bioreactors were sterilized and assembled aseptically before launch.

“The bioreactors were sterilized and aseptically assembled before launch.”

May combine two claims.

Because the ISS A1 batch 1-3 results until day 27 (~650 h) were similar to those of the on-ground GM3 reactor identified as having a stirrer issue, it was concluded that the same difficulty occurred on the ISS reactor.

“Considering the results of ISS A1 batch 1-3 until day 27 (~650h) are similar to the results obtained for on-ground GM3 reactor that has been identified as a reactor that has encountered a stirrer issue, it is concluded that the same difficulty has occurred on the ISS reactor.”

May combine two claims.

Operating GM3 with only external-loop mixing led to heterogeneity of the liquid phase and to gas transfer limitation in the liquid boundary layer surrounding the membrane surface.

“leading to heterogeneity of the liquid phase and gas transfer limitation in liquid boundary layer surrounding the membrane surface.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The pH prediction model was first described by Achard et al. and later used by Cogne et al. and Ifrim et al.

“The model was first described by Achard et al. (1994) and used by Cogne et al (2003 a ) and for the prediction of pH in a toric PBR with pH control by periodic gas CO2 pulses (Ifrim et al, 2014).”

• cites Achard et al. (1994) sourceNot checked — no full text of the source
• cites Cogne et al (2003 a )Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Ifrim et al, 2014 sourceNot checked — no full text of the source

Classified as probably not a substantial claim. May combine two claims.

Each reactor was run with the same timeline and the same incubation conditions.

“Each of the reactors was run following the same timeline and the same incubation conditions.”

May combine two claims.

Except for the initial biomass concentration, which could not be strictly controlled and affected the early growth phase, all reactors were operated under the same conditions of temperature, light and reactor design.

“Except the initial biomass concentration, which could not be strictly controlled, impacting the early growth phase (lag phase and adaptation phase), all reactors were operated in same conditions (temperature, light, reactor design).”

May combine two claims.

The micro photobioreactor was operated at an incident light flux q0 of 7.6 or 9.8 W.m-2, which ensures that light-inhibiting conditions are never reached, even at start-up with low biomass concentration.

“Therefore the working conditions for this micro PBR were fixed at a light incident flux q0 of 7.6 or 9.8 W.m -2 , which guaranties never to be in such light inhibiting conditions, even at start-up with a low biomass concentration (Figure 5b).”

May combine two claims.

On the ground, fluorescence measurements take about 20 minutes, so biomass sedimentation occurs and makes optical density values unreliable.

“Only pressure results are presented; fluorescence measurements require about 20 min, so that on ground biomass sedimentation occurs leading to a nonreliable value for OD.”

• AssumptionRests on an assumption: Biomass concentration is directly correlated with optical density.

May combine two claims.

Cumulative pressure was a good way to compare the different batches and to discriminate reactors with low oxygen production.

“The cumulative pressure was a good way to compare the different batches (Figure 9) and to discriminate reactors with low oxygen production.”

Classified as probably not a substantial claim.

Arthrospira-B is the first spaceflight experiment aimed at direct online measurement of oxygen production rate.

“It must be outlined that Arthrospira-B is the first space flight experiment targeting a direct and on-line measurement of rates (oxygen production rate) offering a new and insightful investigation on time derivatives variables instead of integral variables such as biomass concentration permitting the assessment of microgravity effects onto the behaviour of cellular metabolism.”

May combine two claims.

The theoretical oxygen production yield is constant for a constant light flux and is predicted to be 1.9 gO2/gX by the stoichiometric equation.

“Theoretically /! is constant for a constant light flux and is predicted equal to 1.9 gO2.gX -1 by the stoichiometric equation.”

Classified as probably not a substantial claim.

All inocula for the space and ground experiments came from the same preculture medium to avoid differences in physiological state.

“All the inoculums (for space and ground experiments) came from the same preculture medium in order to prevent any physiological state difference.”

May combine two claims.

The increase in gas pressure results from oxygen production by Limnospira indica PCC8005, so online pressure measurement allows calculation of the instantaneous oxygen production rate and the cumulative oxygen produced.

“The gas pressure increase is the result of the oxygen production by Limnospira indica PCC 8005, so that online gas pressure measurement permits to calculate the instantaneous oxygen production rate rO2, and the total (or cumulated) oxygen produced (assuming no gas accumulation in the liquid).”

• cites Cogne et al (2003 c )Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• AssumptionThe authors state this as an assumption: No gas accumulates in the liquid.

May combine two claims.

The energy transducing process can be described by the JATP/Jcov ratio, called the P/2e ratio, and treated with linear thermodynamics of irreversible processes.

“It was demonstrated (Dauchet et al. 2016) that the energy transducing process can be described by the ratio (JATP)/(Jcov), which is termed the P/2e -ratio, and thus can be handled with the theory of the linear energy converter in terms of Linear Thermodynamics of Irreversible Processes (LTIP)”

• cites Dauchet et al. 2016 sourceNot checked — no full text of the source

May combine two claims.

The recovery of normal stirring in ISS A1 batch 4 shows the reversibility of the malfunction, as often observed on ground for this type of dysfunction.

“showing the reversibility of the malfunction as it has been often observed on ground for this case of dysfunction.”

Classified as probably not a substantial claim.

It remains difficult to distinguish whether observed effects are caused directly by microgravity on cells or are cellular responses to other environmental changes produced by microgravity.

“Therefore, it is still difficult to know if the effects observed are a direct consequence of the microgravity on the cells or a cellular response to other environmental changes due to microgravity (such as partial pressure gradients of dissolved”

Probably not a substantial claim: may not pass S3 (load-bearing).

The concept and demonstration of a space-compatible membrane photobioreactor were first developed in the early 2000s.

“The concept and demonstration of the space compatible membrane photobioreactor was first developed in early 2000 (Cogne et al, 2003 a, b ; Cogne et al., 2005).”

• cites Cogne et al, 2003 a, bNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Cogne et al., 2005 sourceNot checked — no full text of the source

Classified as probably not a substantial claim. May combine two claims.

A review of algal research in space concluded that data remain limited and that no experiment has successfully reported in-flight growth rate of algae.

“Niederwieser et al. (2018 b ) have reviewed the algal research in space, concluding that even though a large number of spaceflight experiments were conducted (mainly with Chlorella sp.), data are still quite limited, and no experiments have been successfully reported in-flight growth rate of algae.”

• cites Niederwieser et al. (2018 b ) sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

The ISS flight experiment was reproduced on the ground at the same time using the same hardware.

“The ISS flight experiment (reactors A1, A4, B1, B4) was reproduced on ground at the same time with the same hardware (i.e.ground reactors GM1, GM2, GM3, GM4).”

Probably not a substantial claim: may not pass S3 (load-bearing).

Arthrospira-B was the first experiment of its kind to have an active microbial bioreactor running in space with online remote monitoring of the bioprocess.

“This experiment was the first of its kind, having an active microbial bioreactor activated and running in space, with on-line remote monitoring of the bioprocess.”

May combine two claims.

When the P/2e ratio exceeds 1.5, the light energy absorbed by the microorganisms is above their metabolic capacity and can cause physiological limitations.

“For P/2evalues greater than 1.5, the light energy absorbed by the microorganisms is above their metabolic capacities and can lead to physiological limitations.”

May combine two claims.

Technical issues reduced the number of results, and a definitive conclusion on whether microgravity influences the growth of Limnospira indica PCC8005 remains difficult to assess.

“But the technical issues encountered have reduced the number of results and a definitive conclusion on the influence or not of the microgravity on the growth of Limnospira indica PCC8005 remains difficult to assess.”

May combine two claims.

This behaviour was observed both on ground and on ISS, leading to higher dissolved oxygen concentrations in the liquid phase and therefore inhibiting biomass growth.

“This behaviour has been observed both on ground and on ISS, leading to higher oxygen dissolved concentrations into the liquid phase, therefore inhibiting biomass growth.”

May combine two claims.

The lower oxygen productivity in a non-perfectly mixed liquid phase may be due to the presence of gas bubbles in the liquid phase and to limiting gas/liquid transfer across the liquid boundary layer at the membrane surface.

“The lower oxygen productivity in non-perfectly mixed liquid phase may be due to presence of gas bubbles into the liquid phase and limiting gas / liquid transfer across the liquid boundary layer at the surface of the membrane.”

May combine two claims.

Consequently, the terrestrial bioreactor growth model is completely applicable for representing 0-g conditions, provided that modifications of physical environmental variables have been correctly assessed by a mechanistic approach in the model.

“Consequently, the terrestrial bioreactor growth model is completely applicable for representing 0-g conditions, provided the modifications of physical environmental variables have been correctly assessed by a mechanistic approach in the model.”

May combine two claims.

A complete model of pH reconstruction using element and electrolyte balances was derived and used to reconstruct the post-flight pH profiles of the cultures.

“A complete model of pH reconstruction using element and electrolytes balances was derived and used to reconstruct post-fight the pH profiles of the cultures.”

May combine two claims.

The sudden re-increase in O2 production rate in ISS reactor A1-b3-b4 confirms this explanation and was interpreted as an unblocking of the stirrer.

“Moreover, the sudden re-increase in O2 production rate in ISS reactor A1-b3-b4 confirms this explanation and was interpreted as an unblocking of the stirrer.”

May combine two claims.

In microgravity, growth under bicarbonate-pH limiting conditions was less affected than under ground conditions, possibly due to the higher CO2 fraction in the gas used to flush the IEC on ISS.

“In microgravity the growth in such bicarbonate-pH limiting condition was less affected than in ground conditions, maybe due to higher CO2 fraction in the gas used to flush the IEC on ISS.”

May combine two claims.

This behaviour could be explained either by a non-perfectly mixed liquid phase (GM3 had stirrer issues) and/or by the presence of a gas bubble in the liquid, leading to an increased gas buffer volume and cushioning the pressure increase.

“This behaviour could be explained either by a non-perfectly mixed liquid phase (GM3 had indeed issues with the magnetic stirrer) and/or by the presence of a gas bubble into the liquid, leading to an increased gas buffer volume and consequently to cushion the pressure increase.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Niederwieser et al. (2018a) discussed the influence of increased CO2 partial pressure on algae growth in spacecraft conditions and gave similar conclusions for algal growth rates.

“Niederwieser et al. (2018 a ) has discussed the influence of increased CO2 partial pressure on algae growth in spacecraft conditions and they have given similar conclusions for the growth rates of algae.”

• cites Niederwieser et al. (2018 a ) sourceNot checked — no full text of the source

May combine two claims.

The pressure profile was better predicted than for the ground experiment because environmental parameters (pressure, humidity, composition) on board ISS and in the Biolab facility were better controlled than for the ground experiments.

“The pressure profile was better predicted than for ground experiment because environmental parameters (pressure, humidity, composition) on-board ISS and of Biolab facility were better controlled than for the ground experiments.”

May combine two claims.

This confirms that gas bubbles in the liquid compartment can cause small changes in the gas/liquid volume ratio, which in turn can have a significant effect on gas pressure evolution.

“This confirms that the presence of gas bubbles in the liquid compartment can lead to small changes in the gas / liquid volume ratio, which in turn can that have a significant effect onto the gas pressure evolution.”

May combine two claims.

Even though the number of replications is insufficient for firm conclusions, it can be claimed that beyond technical issues it is possible to achieve similar productivities and rates of biomass and oxygen production on ground and in microgravity.

“Even considering that the number of replications is not sufficient to draw firm conclusions, it can be claimed that beyond technical issues it is possible to achieve similar productivities and rates of production biomass and oxygen on ground and in microgravity.”