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Title: Influence of engineering variables upon the morphology of filamentous molds

Abstract

A model has been described for the influence of growth rate and shear stresses in the fermentor upon the morphology of filamentous molds. The main concept of this model is the dynamic equilibrium between growth and breakup of the hyphae. The latter has been approached according to well-known engineering theories for dispersion of physical systems. Experiments to verify the model with a strain of Tenicillium chrysogenum in batch and continuous culture revealed that the length of the mycelial particles increased with increasing' growth rate and decreased with increasing power input per unit mass in the fermentor. Although this was qualitatively in agreement with the presented model, quantitatively the model had to be rejected. Variation of the tensile strength of the hyphae with age and culturing conditions could have been one of the causes of disagreement. Oxygen tension, varied independently from stirrer speed, in the range of 12-300 mm Hg was shown to have no influence upon the morphology. With respect to the question of possibly using high-energy inputs in industrial mold fermentation in order to decrease hyphal length and suspension viscosity, it was concluded that this is of little practical value. A substantial decrease in hyphal length requires an enormousmore » increase in energy input.« less

Authors:
;
Publication Date:
Research Org.:
Biotechnology Group, Dept of Chemical Engineering, Delft Univ of Technology, Saffalaan, 9, 2628 BX Delft, the Netherlands
OSTI Identifier:
6720949
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biotechnol. Bioeng.; (United States); Journal Volume: 23:1
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; 59 BASIC BIOLOGICAL SCIENCES; PENICILLIUM; CULTIVATION TECHNIQUES; MORPHOLOGY; BATCH CULTURE; CHEMICAL REACTORS; CONTINUOUS CULTURE; CULTURE MEDIA; FUNGI; GROWTH; MATHEMATICAL MODELS; MYCELIUM; BODY; PLANT TISSUES; PLANTS; TISSUES 140504* -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989); 550700 -- Microbiology

Citation Formats

Van Suijdam, J.C., and Metz, B. Influence of engineering variables upon the morphology of filamentous molds. United States: N. p., 1981. Web. doi:10.1002/bit.260230109.
Van Suijdam, J.C., & Metz, B. Influence of engineering variables upon the morphology of filamentous molds. United States. doi:10.1002/bit.260230109.
Van Suijdam, J.C., and Metz, B. 1981. "Influence of engineering variables upon the morphology of filamentous molds". United States. doi:10.1002/bit.260230109.
@article{osti_6720949,
title = {Influence of engineering variables upon the morphology of filamentous molds},
author = {Van Suijdam, J.C. and Metz, B.},
abstractNote = {A model has been described for the influence of growth rate and shear stresses in the fermentor upon the morphology of filamentous molds. The main concept of this model is the dynamic equilibrium between growth and breakup of the hyphae. The latter has been approached according to well-known engineering theories for dispersion of physical systems. Experiments to verify the model with a strain of Tenicillium chrysogenum in batch and continuous culture revealed that the length of the mycelial particles increased with increasing' growth rate and decreased with increasing power input per unit mass in the fermentor. Although this was qualitatively in agreement with the presented model, quantitatively the model had to be rejected. Variation of the tensile strength of the hyphae with age and culturing conditions could have been one of the causes of disagreement. Oxygen tension, varied independently from stirrer speed, in the range of 12-300 mm Hg was shown to have no influence upon the morphology. With respect to the question of possibly using high-energy inputs in industrial mold fermentation in order to decrease hyphal length and suspension viscosity, it was concluded that this is of little practical value. A substantial decrease in hyphal length requires an enormous increase in energy input.},
doi = {10.1002/bit.260230109},
journal = {Biotechnol. Bioeng.; (United States)},
number = ,
volume = 23:1,
place = {United States},
year = 1981,
month = 1
}
  • The half-width values of the X-ray diffract profiles are frequently used to characterize the static strength of a strengthened surface, or the depth distribution of this mechanical parameter, in a strengthened surface layer, especially in a shot-peening affected layer. However, for the unpeened surface and the base material of the shot-peened specimen of an alloy steel treated in hard state, the experimental results shown in this article indicate that uniaxial tensile or compressive plastic deformation increases the yield strengths while it decreases the half-width values. The half-width values of the shot-peened surface and surface layer greatly decrease, whereas the yieldmore » strength of this surface remarkably increases. Accordingly, in the authors` opinion, the half-width values could not correctly describe the static strengths of hard metallic materials, and, contrary to the viewpoint put forward by a lot of researchers, the shot-peened surfaces of such materials are work hardened instead of work softened. A model demonstrating that plastic deformation reduces the half-width values by decreasing the second kind internal stresses is developed.« less
  • Axenic cultures of the filamentous cyanobacterium LPP OL3 were incubated with samples of uranium-bearing coal from a German mining area. The influence of leaching parameters such as coal concentration, initial biomass, particle size, temperature, and composition of the growth medium on the leaching of uranium from the ore by the cyanobacterial strain was studied. When low pulp densities were applied, the yield of biologically extracted uranium was optimal (reaching 96% at 1% (wt/vol) coal) and all released uranium was found in the culture liquid. Above 10% (wt/vol) coal in the medium, the amount of cell-bound uranium increased. Initial biomass concentrationmore » (protein content of the cultures) and particle size were not critical parameters of leaching by LPP OL3. However, temperature and composition of the growth medium profoundly influenced the leaching of uranium and growth of the cyanobacterium. The yield of leached uranium (at 10% (wt/vol) coal) could not be raised with a tank leaching apparatus. Also, coal ashes were not suitable substrates for the leaching of uranium by LPP OL3. In conclusion, the reactions of the cyanobacterium to variations in leaching parameters were different from reactions of acidic leaching organisms.« less