The composting method only works for mushrooms which decay straw. Most valuable mushrooms are not decay organisms. Some grow within tree roots, which includes truffles and boletes. Other mushrooms feed on bacteria in the soil, which includes Matsutake and morels.

All mushrooms will grow on glucose. Every cell above the bacterial level requires glucose and will synthesize it if not available. But a growing procedure using glucose has not been created, because there are too many complexities and unknowns. So I'm working on a procedure for growing mushrooms on glucose.

This subject began in graduate school at the University of Arizona, where I studied yeast physiology. The yeast that I studied (Nadsonia fulvescens) had the same basic control mechanisms as mushrooms. This allowed me to acquire detailed information which would not have been possible otherwise. The physiology of filamentous fungi is nearly unstudied, because mycelium cannot be put in liquid and aerated, as yeasts and bacteria can.

One of the important mechanisms which I found in Nadsonia yeast is called endotrophism. It means nutrition from within. It means the yeast formed spores in distilled water. Nadsonia needed to be endotrophic as an adaptation for growing on tree sap. When rain washes the sap away, the yeast cells are left without nutrients. They then forms spores from the reserves within the cells.

Soil mushrooms are also endotrophic. They accumulate mycelial mass for a few months and then channel the mass into a mushroom very rapidly--often in one day. This allows the mushroom to form rapidly, so drying or insects don't destroy it before spores get out.

The other important mechanism is a peak in the energy level as ATP which triggers the process of differentiation. This mechanism was first suggested for yeasts by A.F. Crows in 1968. He used the indirect evidence of energy metabolism to show a correlation with yeast sporulation. I showed more direct evidence through nitrogen metabolism. A depletion of nitrogen creates a peak in the ATP level, because synthesis cannot occur without nitrogen. So ATP is not used for synthesis, while energy metabolism can continue to create ATP. Without ATP being used but still being created, a peak in the ATP level occurs.

The ATP trigger mechanism is a method of assuring adequacy before differentiation occurs. When the cells can reach a peak in the ATP level, it means there are adequate cell machinery and energy sources available for completing the process.

When recognized, this mechanism is visible in all fungi, particularly mushrooms. When mushrooms are grown by the composting method, a casing layer of peat moss is placed over the mycelium, and mushrooms come up through the casing. About a month is required for mycelium to grow on the compost, and about 6 weeks is required for the mycelium to grow up through the casing. The mycelium gets little oxygen while growing through the casing, which slows down the process. When the mycelium gets to the surface, a mushroom forms at that point. The only difference between inside the casing and on the surface is oxygen availability. The only thing oxygen does is generate ATP through respiration. So there is a peak in the ATP level where the mycelium gets to the surface.

What happens in the soil is that the thickening of mycelium creates a shortage of oxygen towards the bottom of the mycelium. There is little oxygen in the soil, because it gets used up fast, and water seals out oxygen.

A shortage of oxygen down low starts the differentiation process. Without oxygen, very little ATP can be generated. A small amount results from metabolic processes other than respiration. There is a reduced energy carrier called NADH which carries energy from the metabolic processes to the respiratory system. It has a high energy electron. As that electron spins through the respiratory chain system, it energized three ATP molecules. The electron which gave up much energy then attaches to oxygen. So oxygen must be available to make it work.

If oxygen is not available, the NADH carrier continues to be energized and accumulates. With mushrooms, the accumulated NADH is channeled through the mycelium to the surface where oxygen is available and results in a sharp peak in the ATP level at the surface. The resulting ATP peak causes a mushroom to form on the surface.

There is a method of growing the common mushroom (Agaricus) on liquid nutrients and glucose. It was designed for teachers in a classroom and is not assumed to be practical for commercial production. Vermiculite (puffed mica) is placed in a one liter glass beaker and sterilized. Sterile, liquid nutrients with glucose are poured in and inoculated. After 3 weeks, the mycelial growth is covered with peat moss casing. Mushrooms emerge in another 2-4 weeks, usually around the edge where there is more oxygen available.

There is a strange reason why it works. Evaporation causes the liquid level to drop, which strings mycelium over the vermiculite in a three dimensional manner. Otherwise, the mycelium would be almost two dimensional on the surface of the liquid. Nutrients would not be concentrated enough for surface growth on a liquid, but evaporation increases the concentration of nutrients and resulting mycelium.

Numerous other examples of mushrooms growing under unusual conditions show how mushrooms respond.