How turbo yeast fermentation works
Yeast cells have one main purpose in life and that is to reproduce. In order to do this, it needs food (sugar or things containing sugar, such as molasses etc). But it also needs vitamins and minerals and some other "trace" components in order to utilise the food well. One such important component is oxygen. With plenty of oxygen around, the yeast cells will reproduce forever.
Alcohol is a byproduct, when there is not enough oxygen present, the yeast instead produces alcohol which unfortunately in the end is toxic to the yeast. Alcohol is produced when the six carbon atoms in the glucose are broken down only partially and the result is ethanol. In order to do this in a pure solution of glucose and water, it is essential that there are a certain level of amino acids, minerals and vitamins present. Without these extra "nutrients" you would get very little alcohol. A good turbo yeast will contain a chemically well defined nutrition mix which contains exactly what the yeast will need for production of alcohol.
By-products in alcohol fermentations
During fermentation, yeast cells will not only produce alcohol although it's the main component. There is a vast number of other products created as by-products from the fermentation, sometimes called fusels or volatiles.
These other (unwanted) products are mainly higher alcohols (penthanol etc), esters and miscellaneous acids etc. Some of these are required for a wine to taste like wine and not like alcohol diluted with fruit juice but others will contribute with off flavours so in a turbo yeast fermentation, it is preferred to get as little volatiles as possible.
A good turbo yeast will produce less off-flavours
A distillation following the fermentation of the wash will remove some of the off flavours, further treatment with charcoal (activated carbon) after (actually before as well sometimes) distillation will remove others.
The construction of a turbo yeast will have a large impact on exactly which volatiles are produced during fermentation. To get a very pure fermentation it is sometimes necessary to sacrifice some speed which is why most of the "pure turbo yeasts" take a bit longer than the extreme speed ones such as the Alcotec 24 turbo yeast.