An aseptic pilot bioreactor for solid substrate cultivation processes

Agosín, Eduardo; Pérez-Correa, Ricardo; Fernández, Mario; Solar, I.; Chiang, Luciano E.

doi:10.1007/978-94-017-1711-3_20

Cited by 8 publications

(3 citation statements)

References 3 publications

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“…This type of operation has been used by various workers with the bioreactor operating as a packed-bed for the majority of the fermentation, but with intermittent mixing events during which water is added (Durand and Chereau 1988;Xue et al, 1992;Chamielic et al, 1994;Ellis et al, 1994;Fernandez et al, 1996;Agosin et al, 1997;Bandelier et al, 1997). With this mode of operation, between the mixing events the substrate water activity can potentially fall to values which limit growth, and therefore the model must describe how the substrate water activity changes over time.…”

Section: Introductionmentioning

confidence: 99%

A two‐phase model for water and heat transfer within an intermittently‐mixed solid‐state fermentation bioreactor with forced aeration

Meien

Mitchell

2002

Biotech & Bioengineering

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A two-phase dynamic model is developed that describes heat and mass transfer in intermittently-mixed solid-state fermentation bioreactors. The model predicts that in the regions of the bed near the air inlet there can be significant differences in the air and solid temperatures, while in the remainder of the bed the gas and solid phases are much closer to equilibrium, although there can be differences in water activity of around 0.05. The increase in the temperature of the gas as it flows through the bed means that it is impossible to prevent the bed from drying out, even if saturated air is used at the air inlet. The substrate can dry to water activities that severely limit growth, unless the bed is intermittently mixed, with the addition of water to bring the water activity back to the desired value. Under the conditions assumed for the simulation, which was designed to mimic the growth of Aspergillus niger on corn, two mixing events were necessary, one at 17.4 and the other at 27.9 h. Even though such a strategy can minimize the restriction of growth by water-limitation, temperature-limitation remains a problem due to the rapid heating dynamics. The model is obviously a useful tool that can be used to guide scale-up and to test control strategies. Such a model, describing the non-equilibrium situation between the gas and solid phases, has not previously been proposed for solid-state fermentation bioreactors. Models in the literature that assume gas-solid temperature and moisture equilibrium cannot describe the large temperature differences between the gas and solid phase which occur within the bed near the air inlet.

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Section: Introductionmentioning

confidence: 99%

A two‐phase model for water and heat transfer within an intermittently‐mixed solid‐state fermentation bioreactor with forced aeration

Meien

Mitchell

2002

Biotech & Bioengineering

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“…The process was carried out in a 200 kg capacity aseptic pilot bioreactor, under controlled temperature and bed humidity with the periodic addition of fresh water and under agitation, as described elsewhere [1,6].…”

Section: The Processmentioning

confidence: 99%

“…Relative humidity showed certain spikes that are not representative of the physical process [1]. Even though the vapour is introduced into the air stream using an on/off mechanism, the measurement of the relative humidity is done in the pre-mixing chamber of the reactor, hence a smoother trend is expected.…”

Section: H Gimentioning

confidence: 99%

Data processing for solid substrate cultivation bioreactors

Lillo

Pérez-Correa

Latrille

et al. 2000

Bioprocess Engineering

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Successful scaling up of Solid Substrate Cultivation (SSC) bioreactors has been hampered by the lack of reliable models that describe such processes satisfactorily. Even though experimental data may be available for model development, data analysis is hindered by system heterogeneity and noisy measurements. This work presents a data processing procedure for periodically agitated SSC ®xed bed reactors. The procedure considers several steps. First, all measurements were pre-processed on-line during the cultivation using a low pass fourth order Butterworth digital ®lter. Then, using this preprocessed data, the average bed temperature, evaporation rate, removed heat, and CO 2 production rate were computed off-line. The variables used to compute the evaporation rate and the removed heat were smoothed off-line with a peak shaving algorithm and a non-delay inducing forward/backward moving average scheme. Variables associated with biomass growth (CO 2 and metabolic heat) are known to evolve slowly. Hence, these were reprocessed with a smoothing procedure in order to diminish the effects of bioreactor heterogeneity. Here, moving average smoothing was applied using a larger window than for other variables, and determined empirically in order to smooth the pre-processed data and extract its real trend. The whole procedure was assessed with data from a 200 kg capacity SSC bioreactor in the cultivation of a ®lamentous fungus (Gibberella fujikuroi) on wheat bran. List of symbolsC gi inlet air CO 2 content [kg CO 2 /kg dry air ] C go outlet air CO 2 content [kg CO 2 /kg dry air ] C pd.a speci®c heat of the dry air [J/kg K] C pv water vapour speci®c heat [J/kg K] CPR CO 2 production rate [kg CO 2 /h] G dry air¯ow rate [kg a.s. /h] H combágluc enthalpy of glucose combustion [J/mol glucose ] H gi inlet air relative humidity [%] H go inlet air relative humidity [%] k combágluc energy rate between the global production and the produced by the combustion of glucose [J global /J glucose ] Q g heat removed by the gas; it includes convection and evaporation [J/h] Q m metabolic heat generated by the microorganism [J/h] RQ Mass Respiratory quotient [kg CO 2 akg O 2 ] T b.a. average bed temperature [°C] T bed bed temperature [°C] T gi inlet air temperature [°C] T go outlet air temperature [°C] W water evaporation rate [kg/h] w cutting frequency [mHz] Y gi speci®c humidity of the inlet air [kg water /kg dry air ] Y go speci®c humidity of the outlet air [kg water /kg dry air ] Y g/O rate between consumed glucose and consumed oxygen [mol gluc /kg O 2 ] %CO 2 inlet air CO 2 content [mm 3 CO 2 / 100 mm 3 dry air ] DHr global heat of reaction [J/kg O 2 ] DP pressure loss through the bed [mm H 2 O ] k w water latent heat [J/kg] 1 Introduction Solid substrate cultivation (SSC) has a number of advantages over submerged cultivation such as higher yields while using lower cost raw materials. Nevertheless, this technology does have certain limitations: The lack of reliable control and optimisation strategies hamper scaling-up the processes to commerci...

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Solid Substrate Fermentation, Automation

Agosín

1999

Encyclopedia of Bioprocess Technology

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An aseptic pilot bioreactor for solid substrate cultivation processes

Cited by 8 publications

References 3 publications

A two‐phase model for water and heat transfer within an intermittently‐mixed solid‐state fermentation bioreactor with forced aeration

A two‐phase model for water and heat transfer within an intermittently‐mixed solid‐state fermentation bioreactor with forced aeration

Data processing for solid substrate cultivation bioreactors

Solid Substrate Fermentation, Automation

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