Normally you extract sugar cane juice from sugar cane and there are 2 routes: production of sugar or production of ethanol (you can produce also other products, but ltes to concentrate only in these two). To produce sugar the juice is treated to remove impurities and, after concentration sugar is crystallized and the liquid phase separated. You can use this phase to produce ethanol, by dilution and fermentation. The same you can do directly with the juice: adjust sugar content to fermentation. After fermentation, the "wine", a diluted ethanol solution has to be distillated. During distillation several impurities of ethanol, like fusel oil, are removed. You can increase etahnol purity by physical treatments or re -distilling it.

The quantity of sugar you crystallize in a process is flexible, since you can use the juice straight way to fermentation. Market prices normally dictates the demand of production of sugar or ethanol.

According to Sullivan and Frost, 2008 a liter of bioethanol can be produced directly from 15 kilograms of sugar cane and 4 kilograms of molasses, respectively (Research and Markets, 2008 (http://www.researchandmarkets.com)). Mumias Sugar Company’s prefeasibility study indicates that from a tonne of molasses about 220 litres of ethanol (4.545455kg/l) would be produced (Mumias Sugar, 2008)

the amount of yeast doesnt effect the fermentation, you should control the growth rate of enzymes during fermentation. You can add DAP(Di ammonium Phospahte) and other related chemcal which will accelerate their growth and also it is again an exothermic reaction, the temperature should be carefully conrolled. If temperature exceeds 35 C, bacteria will dye and it will effect the process.

http://www.doiserbia.nb.rs/img/doi/1450-7188/2012/1450-71881243325V.pdf

https://www.theseus.fi/bitstream/handle/10024/38208/Shang_Xueying.pdf?sequence=1

https://ir.dut.ac.za/bitstream/10321/888/1/nofemele_sure_et_al_2012.pdf

Article Production of Bio-ethanol from Molasses by Schizosaccharomyces Species