Litterature on the effect of static magnetic fields on yeast growth

The effect of magnetic fields on the growth of Baker's yeast has, of course, already been studied, but a surprisingly low number of times. I found only a handful of references.

I found some mentions of Pasteur conducting experiments on the effect of magnet on the fermentation of wine. His collected works are available at Bibliothèque Nationale de France but only in non-OCR form. They are quite lengthy and lack an index. I didn't have the patience to read all the 600 pages.

Amongst the more recent studies are a positive report by Brazilian researchers. As you may know, Brazil has some interest in ethanol production by fermentation. The article is well-referenced and is even available here.

Biotechnol Prog. 2001 Sep-Oct;17(5):970-3.
Changes in Saccharomyces cerevisiae development induced by magnetic fields.
Motta MA, Montenegro EJ, Stamford TL, Silva AR, Silva FR.

Departamento de Biofísica e Radiobiologia, Universidade Federal de Pernambuco, Cidade Universitaria 50670.901, Brazil.

Saccharomyces cerevisiae cultures exposed to 110 mT and 220 mT steady magnetic fields (SMF) were studied to observe eventual induced growth alterations and changes in metabolic activity. Cell mass (biomass) growth was evaluated by light spectrometry, and metabolic alterations were estimated on the basis of the CO2 pressure produced and by the culture media pH changes, measured at the beginning and the end of the observation. The yeast strain DAUFPE-1012, cultivated in a nonaerated liquid agar Sabouraud glucose medium, was exposed to SMF generated by NdFeBr magnets. Results showed alterations induced by 220 mT SMF as an increment in cell proliferation (1.84%) and an increased CO2 production (36.1%) as compared to control groups. Furthermore, the initial-to-final pH difference in 220 mT SMF exposed cultures was higher than the 110 mT SMF and the control values. The whole acidification and the rise in CO2 production observed after 220 mT SMF exposure did not correspond to the biomass growth values, as compared to the other cultures, and was apparently provoked by a enhancement in the cellular metabolic rate. This technique becomes very promising for future biotechnological applications in fermentative processes.

PMID: 11587592 [PubMed - indexed for MEDLINE]

The following patent is also interesting:
Apparatus and method for exposing seeds to a magnetic field.

Replication of yeast experiment

I have trimmed the tubes to equalize their inner volume to about 12 ml. I am now repeating yesterday's experiment, but using south poles. I took all mesures to avoid the previously mentioned pitfalls.

Here are the results.

South-pole treated samples slightly outperform untreated samples; the difference is not very significant. But there is more.

First, although I trimmed the larger, green silicone tubes so that they have the same volume as the others, they still consistently give higher results -- see the upper two curves.

Second, there is significantly more variability in the control group than in the treatment group. I think this might be due to light. I simply put a drape over the flasks in an attempt to uniformize the amount of light they receive. However, the higher control flask that is not using a large tube sits in the shadow of a distant compact fluorescent lamp, while the other flasks do not.

Tomorrow, I will build an opaque box to protect the flasks.