Medical/biological study (experimental study)

Extremely low frequency magnetic field effects on metabolite of Aspergillus niger med./bio.

By: Gao M, Zhang J, Feng H

Published in: Bioelectromagnetics 2011; 32 (1): 73-78

Aim of study (acc. to author)

To study the effect of the extremely low frequency magnetic field on the fermentation process (citric acid and cellulase production) of Aspergillus niger.

Background/further details

The biochemically versatile fungus Aspergillus niger produces a wide array of acids and enzymes. This metabolic diversity and its ability to use a large amount of different carbon sources make Aspergillus niger a valuable cell factory for applications in many different industrial processes.

Endpoint

cell function: fermentation process (citric acid and cellulase production) of Aspergillus niger

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 4 h, 6 h or 8 h	magnetic flux density: 1 mT magnetic flux density: 0.2 mT (exposure only for 4 h)

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	continuous for 4 h, 6 h or 8 h

Exposure setup

Exposure source	coil(s)
Chamber	six sets of 3 cylindrical coils wrapped with magnetic shielding material, fastened to the rocking bed and rotated at 200 rpm; each coil 600 mm long with an inner diameter of 100 mm; outer diameters of the coils: 114 mm, 120 mm, 126 mm, 132 mm, 138 mm and 144 mm; number of threads of wire with 2 mm diameter: 1200, 1800, 2400, 3000, 3600 and 4200; cultures placed in 80 mm heigh glass shake flasks with a diamter of 60 mm on a non-conductive stand in the middle of each coil; temperature kept constant at 30° C

Exposure source

coil(s)

Chamber

six sets of 3 cylindrical coils wrapped with magnetic shielding material, fastened to the rocking bed and rotated at 200 rpm; each coil 600 mm long with an inner diameter of 100 mm; outer diameters of the coils: 114 mm, 120 mm, 126 mm, 132 mm, 138 mm and 144 mm; number of threads of wire with 2 mm diameter: 1200, 1800, 2400, 3000, 3600 and 4200; cultures placed in 80 mm heigh glass shake flasks with a diamter of 60 mm on a non-conductive stand in the middle of each coil; temperature kept constant at 30° C

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	1 mT	-	measured	-	-
magnetic flux density	0.2 mT	-	measured	-	exposure only for 4 h

Exposed system:

intact cell/cell culture
Aspergillus niger

Methods Endpoint/measurement parameters/methodology

cell function: citric acid production (via phenolphtalein titration) and cellulase production (enzyme activity; spectrophotometry)

Investigated system:

cell supernatants

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

Both yield of citric acid and enzyme activity of cellulase increased with increasing exposure time and/or magnetic flux density, but the metabolism of citric acid was more sensitive to the magnetic field than that of cellulase. From the measurement of the metabolism dynamics the authors concluded that the increase in the citric acid production and cellulase enzyme activity started immediately after the magnetic field was switched on.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Hubei Provincial Department of Education in China
Yangtze University, China

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