The Spirupile
A discovery like this does not happen very often. At the end of last year, I have discovered that spirulina culture when grown on foam produces significant amount of electricity. It can also be done using a piece of cloth.
It is an unexplained phenomenon. This Microbial Fuel Cell (MFC) does not work like any other regular one with two chambers and a membrane separating the two half reactions.
It is also the cheapest MFC one can imagine, just salt water, Spirulina Salina, foam and two electrodes made of aluminum foils.
As a good scientist, I have made a negative test without the algae. The amazing thing is that even without the algae, there is already a little bit of current. The foam with saltwater seems to be already a salt battery and a capacitor at the same time. As I understand it, the capacity comes from the multiple units of insulating material with two layers of conductive salts solution on each side. I suppose the current comes from the salts gradient caused by the evaporation of water on the large surface area of the foam. The current hoovered around 170 millivolts and the resistance around 25 kiloOhm. I never have measured any value above 250 millivolt, the threshold to hydrolyze water into hydrogen and oxygen. With the algae, with or without an air pump for agitation, I have reached over 800 millivolt and over a hundred microamp.
The absence of a membrane in a working batterie is a first mystery. Such high tensions is a second mystery. The fact that hydrolysis does not happen directly within the bioreactor is quite puzzling and unintuitive. Furthermore there is a third mystery. These MFC can be pushed to enter in resonance with the electric grid. It can also happens spontaneously. I have measured AC value in the range of hundreds of volts. However I have never manage to get electrocuted from my small fuel cell though. Despite this deception, I still strongly suppose it entered in resonance with the grid. Using my multimeter I was able to follow the variations in frequency of the electric grid, which is published on the internet.
Otherwise they are almost regular batteries. You can wire them up in parallels or in series and get the expected results, for a while. For instance when you hook them up in series the voltage first add up and then, sort of average out.
Another astonishing thing about these batterie is that it is shape dependent. The exact same amount of foam can produce different amounts of tension and current depending on the container shape. It is thus not directly proportional to volume. It is also not directly linked to the amount of cells. A deep green foam won't necessarily produce more current than a light green foam. It suggest that the amount of current is proportional to microscopic organization.
The current produced is very special. It is both AC and a little bit DC sometimes. Since this MFC has no isolating membrane, it has a conductance and thus a resistance. The resistance can range from megaohm to ohm, to negative value... The foam electrostatic properties and the salts ions currents could also be involved. It could either rival or complement the current and the tension produced by the algae. A high resistance is at first quite unintuitive for a porous objects soaked in salt water. The growth support is in itself non conductive and the Spirulina cells growing on it are series of insulant membranes next to one another. Even if we suppose that the current goes through the cells and through the entire colonies, with their coil like shapes, one would expect a high resistance and the generation of a magnetic field dissipating the current. One the other hands, cells have sensitive ions channel that can influence the current a be influence by the current. Cells can have excess electron on their membrane surface. Furthermore their photosystems constantly produce high potential electrons that can not always enter the carbohydrate production chain. It is an experimental fact that these MFC produce an excess of electrons and that they produce a significant amount of current. So when you thing of it, if an external current travel through this circuit and instead of meeting resistance, meets a voltage boost, it would end up with more tension at the end than at the beginning. Thus the resistance would be negative. One can then wonder how the Ohm's law could be respected. Usually the resistance is never negative because the voltage and the current have usually the same sign. A negative resistance value would imply that the tension has an opposite sign to the current. Using in parallel both an analogic amperemeter and a multimeter set on resistance, I have once observed a reverse in current direction when I briefly measured negative resistance. I believe it is the first report of an experimental observation of negative resistance during a current inversion. Who could have thought that sometime, a simple piece of a non conductive material can be better at transmitting current than even the most exotic superconductive material in liquid nitrogen ? Just kidding.
There is another amazing application of this type of MFC. It can be wired to be turned into a electromagnetic field detector with a very high sensitivity. This MFC using a cloth wrapped around a plastic bottle (image above), placed in a glass jar half filed with culture medium, can be wired to be turned into a electromagnetic field detector. This detector has a very high sensitivity. I have realized this when I used a simple DC to AC convertor made of four diodes and a capacitor with my cloth Spirupile. I intended to get rid of the AC current. The tension produced became much lower but directly proportional to the surrounding electromagnetic fields produces by the grid. Turing on or off a nearby AC electric equipment affected the reading on the multimeter, turning up or down the voltage. More surprisingly the electromagnetic field produced by the hands can also be noticed. Sometime one can observe an increase and sometime a decrease in the tension when touching the glass jar with naked fingers. However an electromagnetic field produced by an DC current goes unnoticed. The use of permanent magnets on the cultures themselves don't seems to have any effect on current production either. However using permanent magnets on wire coils using this current appeared to sometime destabilize the production momentarily. In another experiment I have made, the current produced with this battery appears to be attracting the north pole of a compass a dozen (13) degree in the direction of the current. It suggest a magnetization parallel to the current vector instead of perpendicular. It suggest a magnetized population of electrons. It could also explain the fact that two of my electronic multimeters became dysfunctional after a couple weeks. They started to present, first temporarily and then permanently, erratic and resonant values when unplug, even with new batteries.
The amazing sensitivity of biological system to even very weak magnetic field, like the earth magnetic filed is a field of intense research. Electrons in radical pairs are thought to be involved. It is known that quantum response to magnetism in cells exists as demonstrated by Woodward Jonathan, Professor of Magnetoreception, Spin Chemistry, Photochemistry. Such pairs of radical electron are known to be very sensitive to magnetic field. It could explain why the cloth version of the Spirupile can so easily be turned into a very sensitive electromagnetic field detector. Another strange hypothesis I came up with to explain the apparent magnetic properties of this current, is a population of electron with a majority of one spin. There is a biophoton so why wouldn't there be bio-electrons? We know that the photosynthetic proteins are chiral molecules and that they deviates the plane of polarized light in only one direction. As anyone checked if the proteins of the photosystem excite more electron with a specific spin ? Finally we are talking about a sea of electrons under a photon storm. What type of effect could the wave function have in such a special environment ? It is known that electron transfer within protein and in between proteins happens using the tunneling effect. Does the high density culture of cells, pack full of proteins, leads to large scale quantum effects that allow electrons to go over what is normally an unsurmountable barrier? Is it what allows electrons to leave the water of the bioreactor with enough energy to end up hydrolyzing water at the two outside electrodes?
Consortiums could also be involved. My first hypothesis was that the membrane of the MFC was replaced by a multitude of membranes of different cells doing each the half reaction. The Spirupile current would then results from an addition of a multitude of consortiums making small batteries. They would exchange ions in between the membrane and the electrons would stay on their cell surface and travel from cell to cell. One reason I though so is that the current production carries on once the light is turned off. It can even increase for an hour or so before slowly diminishing. In the morning the electricity does not spike up immediately. It suggest an electric production proportional to photosynthetic metabolites degradation. However one reason to favor a tunneling effect hypothesis to a series of consortium is that the phenomenon also works with a cloth of yeasts. The tension is then proportional to sugar concentration and photons don't seems to be essential. I could not spot yeasts in my spirulina culture. However I did spotted a few algae on my cloth full of yeast fermenting sugar. However I currently don't believe it to be very significant as they are few and far between. The two hypothesis are not mutually exclusive and the two could happen simultaneously. Only further experiment can give a definitive answer to all these questions.
Acknowledgments: I really thank the social services of Neuchatel for paying my room and for my food budget used for this research. I also thank the Unine for ignoring me and my research all these years, I would never have discovered this phenomenon otherwise. I also present my excuses for researching so fast and publishing it sometime live and thus not letting any chance to plagiarism, really sorry.