Influence of mold growth on the pressure drop in aerated solid state fermentors

Abstract

The measurement of pressure drop(DeltaP) across an aerated fermentation bed is proposed as alternative on-line sensor for the qualitative and, in some cases, quantitative, macroscopic changes in a static solid state fermentor. An increase in the DeltaP is correlated with the evolution of the different phases of Aspergillus niger growth: germination, vegetative growth, limitation, and sporulation, we observed in the microscope. For the case where the support is not modified during the fermentation and the water content remains constant, i.e., a synthetic resin (Amberlite IRA-900), the gas phase permeability of the bed is directly related to the biomass content. For example, the permeability of the bed is reduced to 5% of the initial value when biomass attains 21 mg dry biomass/g dry support. Biomass was appropriately predicted from the DeltaP measurements in an independent test. Experiments with different initial sucrose solution concentrations showed that biomass could not be produced beyond a certain level (21.5 mg dry biomass/g dry support) which suggests steric limitations. For the case of wheat bran and cane bagasse, the increase in DeltaP was related qualitatively to the evolution in the growth and the morphology of the mold.

Correlation of Biological Activity and Reactor Performance in Biofiltration of Toluene with the Fungus Paecilomyces variotii CBS115145

“…The EC then decreased to an average of 250 g/m 3 of biofilter/h. Similarly to previous experiments, CO 2 production was associated to toluene elimination capacity (9). At day 104, when the average EC was around 250 g/m 3 of biofilter/h, the experiment was stopped, and biomass from various heights of the biofilter was used to measure oxygenase activity.…”

“…The support was prepared as described above, and 55 g was packed in the biofilters (2). Glucose (20 g/liter) was included with the initial medium to favor spore germination and startup.…”

Biomass growth monitoring using pressure drop in a cocurrent biofilter

“…This method has already been used by Auria et al (1993) and Kim and Chang (1986) for different systems. Auria et al (1993) explored the possibility of using pressure drop measurements to estimate the growth of molds in solid-state fermentation.…”

“…This method has already been used by Auria et al (1993) and Kim and Chang (1986) for different systems. Auria et al (1993) explored the possibility of using pressure drop measurements to estimate the growth of molds in solid-state fermentation. They studied gas flows in a laminar regime, monitoring the evolution of the hydraulic permeability, whereas Kim and Chang (1986) worked in turbulent regime, using a packed-bed immobilized enzyme reactor.…”

Bioconversion of biomass: a case study of ligno-cellulosics bioconversions in solid state fermentation

“…Christen et al (1993) successfully monitored the growth of Candida utilis in a bagasse medium in SSF. Auria et al (1993) conducted a study on the influence of mould growth on the pressure-drop in aerated SSF using bagasse and wheat bran. They proposed the measurement of pressure-drop (DELTAP) across an aerated fermentation bed as an alternative on-line sensor for the qualitative and, in some cases, quantitative, macroscopic changes in static SSF.…”