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Rapid Determination, Using Dielectric Spectroscopy, of the Toxicity of Organic Solvents to Intact Cells

1992; Elsevier BV; Linguagem: Inglês

10.1016/b978-0-444-89046-7.50047-3

2212-117X

Gary J. Salter, Douglas B. Kell,

Biofuel production and bioconversion

Abstract Dielectric spectroscopy utilising dual-frequency measurements has been used to study the toxic effects of a number of organic solvents to suspensions of Saccharomyces cerevisie. Solvents of a highly apolar nature, such as hexadecane, were identified as being non-cytotoxic, and thus suitable for use with whole-cell systems. A novel approach to aid biotransformations, using mixed organic solvents, has also been studied. This has revealed that the cytotoxic nature of polar organic solvents, such as octan-l-ol, may be negated by dissolving them first in apolar, non-cytotoxic organic solvents, such as hexadecane, before exposure to the cell suspension. The use of mixed organic solvents with immobilised cell systems was shown to be possible by the growth of Lactobacillus brevis , (immobilised within hollow ceramic microspheres), in the presence of 5% (v/v) octan-l-ol dissolved within 5% (v/v) hexadecane, added to the media. Dispersion of these immiscible solvents was improved by the addition of 5% (v/v) ethanol and 0.05% (v/v) tween 80. Cell growth occurred (as measured by dielectric spectroscopy) over a 70- hour period.