How is methanol produced in regard to yeast? I know that it comes from the fermentation of wood, but can brewer’s yeast (or for that matter, baker’s yeast) produce methanol from it? If I were to make a mash consisting entirely of just sugar and water, with no cellulose present, would there be any risk of methanol being produced by the yeast? Thanks!
Methanol is not produced by fermentation, it’s produced by destructive distillation. Yeast cannot produce methanol (although, oddly enough, some yeasts can metabolize it).
Could you please elaborate on what destructive distillation is? Thanks!
Destructive ditillation is a process in which a material (in this case, wood) is heated (in low oxygen) until it decomposes. The cellulose breaks down into both volatile components (including methanol) and nonvolatile components (“tar”). By limiting the availability of oxygen, the formation of oxidation products is prevented. The volatile components are collected by condensation, just as with simple distillation.
I should mention that destructive distillation is obsolete. The modern method of preparing methanol is based on the direct combination of carbon monoxide gas and hydrogen in the presence of a catalyst.
Just in case there is confusion here (I might be misreading, and if so, I appologize) but Methanol and Ethanol are two different alcohols. Ethanol is made by yeast in fermentation, and this is the “safe” alcohol for humans to consume. Methanol is made as described, and is not something you would want to drink, as it can cause serious illness and death.
Ethanol: CH3CH2OH
Methanol: CH3OH
Hrm, then you’d better go explain that to all the Pichia pastorales I cultured a few years ago. Those yeast could pump out methanol quite nicely. Different genera of yeasts have different enzymes. Saccharomyces cerivasiae produces mostly ethanol as its fermentation waste product (along with carbon dioxide), but other species end up making more methanol.
Destructive distillation can produce methanol, but it’s not the only way to get it.
Do you mean Pichia pastoris? I’ve heard of that metabolizing methanol, but I’ve never heard of it producing methanol. Cite?