Conductimetric assessment of the biomass content in suspensions of immobilised (gel-entrapped) microorganisms

Lovitt, Robert W.; Walter, Robert P.; Morris, Jonathan; Kell, Douglas B.

doi:10.1007/bf00261908

Cited by 22 publications

(6 citation statements)

References 28 publications

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“…We also sought to estimate P using the conductimetric method described [54,55]; however, the cell radii were observed to change significantly in the highly-conducting media necessary for this estimation. In all cases, strict linearity of AC' with "biomass" was observed over the range of cell numbers (volume fractions) studied, which serves to indicate both that the dielectric behaviour assessed was purely due to the presence of the cells and that the dielectric method of biomass estimation would be suitable for use with the animal cells.…”

Section: Resultsmentioning

confidence: 99%

On the audio- and radio-frequency dielectric behaviour of anchorage-independent, mouse L929-derived LS fibroblasts

Davey¹,

Kell²,

Кемп³

et al. 1988

Bioelectrochemistry and Bioenergetics

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Section: Resultsmentioning

confidence: 99%

On the audio- and radio-frequency dielectric behaviour of anchorage-independent, mouse L929-derived LS fibroblasts

Davey¹,

Kell²,

Кемп³

et al. 1988

Bioelectrochemistry and Bioenergetics

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“…where e0 = 8.854 X lo-i2 F/m. We also sought to estimate P using the conductimetric method described [54,55]; however, the cell radii were observed to change significantly in the highly-conducting media necessary for this estimation. In all cases, strict linearity of AC' with "biomass" was observed over the range of cell numbers (volume fractions) studied, which serves to indicate both that the dielectric behaviour assessed was purely due to the presence of the cells and that the dielectric method of biomass estimation would be suitable for use with the animal cells.…”

Section: Resultsmentioning

confidence: 99%

On the audio- and radio-frequency dielectric behaviour of anchorage-independent, mouse L929-derived LS fibroblasts

Davey

Kell

Кемп

et al. 1988

Journal of Electroanalytical Chemistry and Interfacial Electroc

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The utility of dielectric methods as a means for estimating the biomass of animal cells in suspension culture was assessed, using mouse L929-derived LS fibroblasts. The dielectric increment of the /3-dispersion was found to be a linear function of both cell number (30-70 permittivity units per lo6 cells/ml, depending on the batch of cells) and volume fraction in the range measured (up to 1.28 x 10s cells/ml. volume fraction = 0.14). The notional distribution of relaxation times as encompassed in the Cole/Cole a (0.13 kO.03 SD) was rather modest. If the cells were treated as spherical shell capacitors of their observable diameter and number, the apparent capacitance of the plasma membrane was some 1.9-4.0 pFF/cm2. This value significantly exceeded those (0.5-l pF/cm2) usually encountered or claimed, due predominantly to the possession by these cells of numerous plasma membrane protrusions. As the osmolarity of the suspending medium was increased using the non-permeant solute sorbitol, the apparent specific capacitance of the plasma membrane and the Cole/Cole a were increased, whilst the dielectric increment per 10" cells/ml was unchanged. In addition, a secondary /3-dispersion, with a characteristic frequency greater than that of the main P-dispersion, became increasingly prominent as the medium osmolatity was increased. It is proposed that this a,-dispersion is dominated by a Maxwell-Wagner mechanism taking place in the region of the plasma membrane protrusions of these cells.

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“…The two methods give complementary information and perhaps should be used together to assess shelf-life of different formulations. There is a suggestion that assessment of biomass content of alginate pellets may be useful (Lovitt et al, 1986). However, both alginate concentration and microbial cell content could influence oxygen uptake from the formulated pellet (Gosmann & Rehm, 1986).…”

Section: Discussionmentioning

confidence: 99%

Growth of Coniothyrium minitans, Gliocladium roseum, Trichoderma harzianum and T. viride from alginate pellets and interaction with water availability¹

Magan¹,

Whipps²

1988

EPPO Bulletin

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Conidia, chlamydospores and mycelia of Coniothyrium minitans, Gliocladium roseum, Trichoderma harzianum and T. viride were obtained from liquid or solid culture and formulated within alginate pellets. Quantitative assessment of these pellets over a 12‐week period showed a decrease in the number of colony‐forming units (cfu) from about 107 to 103‐104 g‐1 air‐dried pellets. Qualitatively, growth was assessed by direct plating the alginate pellets on rich (potato dextrose agar, PDA) and poor (water agar, WA) substrates. Rate of growth (mm day‐1) from individual pellets was decreased by water potential in the range ‐0.25 to‐2.8 MPa, with growth significantly less on WA than PDA for all species except G. roseum. All species grew from 95 to 100% of direct‐plated pellets on PDA over the water‐potential range tested. However, on WA, interaction between water stress (‐2.8 MPa) and lack of nutrients resulted in a reduction, with less than 30% of pellets of some formulations showing growth. In contrast to the quantitative results, there was little change in the growth rate of test species from pellets over a 12‐week period, particularly on PDA. Growth from pellets could not be conclusively demonstrated in unsterile soil. The shelf‐life and viability of alginate pellets in soil is assessed.

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Conductimetric assessment of the biomass content in suspensions of immobilised (gel-entrapped) microorganisms

Cited by 22 publications

References 28 publications

On the audio- and radio-frequency dielectric behaviour of anchorage-independent, mouse L929-derived LS fibroblasts

On the audio- and radio-frequency dielectric behaviour of anchorage-independent, mouse L929-derived LS fibroblasts

On the audio- and radio-frequency dielectric behaviour of anchorage-independent, mouse L929-derived LS fibroblasts

Growth of Coniothyrium minitans, Gliocladium roseum, Trichoderma harzianum and T. viride from alginate pellets and interaction with water availability¹

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Conductimetric assessment of the biomass content in suspensions of immobilised (gel-entrapped) microorganisms

Cited by 22 publications

References 28 publications

On the audio- and radio-frequency dielectric behaviour of anchorage-independent, mouse L929-derived LS fibroblasts

On the audio- and radio-frequency dielectric behaviour of anchorage-independent, mouse L929-derived LS fibroblasts

On the audio- and radio-frequency dielectric behaviour of anchorage-independent, mouse L929-derived LS fibroblasts

Growth of Coniothyrium minitans, Gliocladium roseum, Trichoderma harzianum and T. viride from alginate pellets and interaction with water availability1

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Growth of Coniothyrium minitans, Gliocladium roseum, Trichoderma harzianum and T. viride from alginate pellets and interaction with water availability¹