Study type: Medical/biological study (experimental study)

Bioreactor coupled with electromagnetic field generator: effects of extremely low frequency electromagnetic fields on ethanol production by Saccharomyces cerevisiae. med./bio.

Published in: Biotechnol Prog 2007; 23 (5): 1091-1094

Aim of study (acc. to author)

To study the effect of extremely low frequency magnetic fields on ethanol production by the yeast Saccharomyces cerevisiae using sugar cane molasses during batch fermentation.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Exposure duration: not specified (fermentation time up to 17 h)
Exposure 2:
Exposure duration: not specified (fermentation time up to 17 h)
solenoid field

General information

Three experiments were conducted: 1) Exposure 1 with 5 mT (maximum distance between magnets) 2) Exposure 1 with 20 mT (minimum distance between magnets) 3) Exposure 1 with 20 mT (minimum distance between magnets) and Exposure 2 (solenoid) sequentially

Exposure 1

Main characteristics
Frequency
Type
Waveform
  • rectangular
Exposure duration not specified (fermentation time up to 17 h)
Additional info permanent magnet exposure
Exposure setup
Exposure source
Chamber Six permanent magnets (square prism, two faces of 4.8 cm x 4.8 cm, 2.4 cm thick), arranged with opposite poles facing (each with 3 in a row). Magnets inserted in a steel box separated horizontally by 2 mm thick iron plates. Distances of the two boxes could be adjusted to supply different magnetic inductions.
Setup Configuration allows to obtain uniform magnetic fields in the space between the magnets, generating a square wave with perpendicular field lines; the field changes (caused by the fluid velocity of 0.6, 0.9, 1.2 and 1.4 m/s flowing between the magnets) mimic an extremely low frequency (ELF) field.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 20 mT maximum measured - -
magnetic flux density 5 mT minimum measured - -

Exposure 2

Main characteristics
Frequency
Type
Exposure duration not specified (fermentation time up to 17 h)
Additional info solenoid field
Exposure setup
Exposure source
Setup 20 cm long double-layered solenoid
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 8 mT - calculated - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

All magnetic field exposures resulted in higher ethanol yield, except 5 mT, which results were similar to the control experiment. Under the best conditions (0.9-1.2 m/s and 20 mT plus solenoid, field 3), the overall volumetric ethanol productivity was approximately 17% higher than in the control experiment. The fermentations with magnetic treatment reached their final stage in less time, i.e. approximately 2 h earlier, when compared with the control experiment (i.e. 15 h).
In conclusion, the data showed that an extremely low frequency magnetic field induces alterations in ethanol production by Saccharomyces cerevisiae and that the magnetic field treatment can be easily implemented at an industrial scale.

Study character:

Study funded by

Related articles