Comments on oxygen transfer within a mold pellet

Abstract

A morphological observation of a fungal fermentation shows the following two contrasting patterns: 1) the mycelia forming aggregates called "pellets" aa fermentation progresses; and 2) the original mycelial broth remains "pulpy" per se. It is claimed by Takahashi et al. that even the same species of mycelia becomes either pellet or pulpy, depending on an inoculum condition of the fermentation. 1

Mass Transfer in Bioreactors

“…These values are similar to those reported for Aspergillus niger (Miura et al1975) and Aspergillus orizae (Kim et al 1983) but lower than (Aiba, S.;Kobayashi,1975;Kobayashi et al 1973). Differences between simulated and experimental data were less than 6 % and differences can be due to: 1.…”

Diffusion of oxygen in alginate gels related to the kinetics of methanol oxidation by immobilized Hansenula polymorpha cells

“…The kinetic problems in oxygen-requiring processes caused by the low solubility of oxygen in water, are not limited to immobilized systems but have also been encountered in mold pellets (Aiba and Kobayashi 1971;Bharvarju and Blanch 1975) and other microbial aggregates (Ngian and Lin 1976). The model of Aiba and Kobayashi (1971) for oxygen diffusion in mold pellets, with the minor changes suggested by Bharvarju and Blanch (1975), has been adapted for Hansenula polymorpha cells entrapped in a barium-alginate gel. The following assumptions were made: (i) the alginate beads are spherical; (ii) oxygen is the only rate-limiting substrate.…”

“…Using the above assumptions, we can describe the process of oxygen diffusion in the alginate matrix and oxygen utilization by the immobilized cells mathematically (for explanation see: Aiba and Kobayashi 1971;Bharvarju and Blanch 1975; (6) The efficiency of an immobilized biocatalyst in terms of the oxidation of a certain substrate can be described with an effectiveness factor t/ (Goldstein 1976) which is defined as the ratio of the rate of oxygen consumption by immobilized cells to that of the free cells. In mathematical form this is expressed as follows: 1)and (2 ):…”

Mathematical Modelling of Fungal Growth

“…For example, Aiba and Kobayashi (1971) described the specific rate of respiration within a pellet as a hyperbolic function of dissolved oxygen concentration: (15.20) C and C represent concentrations of oxygen within the pellet and in the surrounding medium respectively, q' 0, and qo, are the respective respiration rates and Km is a saturation constant. Calculation of the oxygen balance within the pellet requires consideration of both respiration and inward diffusion.…”