3.6. Influence of high inocula concentrations using molasses media
To evaluate the performance of the selected strains and compared with those currently used in distilleries at industrial
scale, it was necessary to reproduce the concentrations of inoculum used on a larger scale. Ethanol production generally recycles yeasts to minimize the time of fermentation. This procedure is based on centrifuging the fermented broth, recycling the yeasts after a pretreatment with sulfuric acid to pH 1 within 1 h. Generally, it is recovered 10% of the volume of the broth and the cream has about 20% dry matter. Thus, the recycled inoculum is about 2% dry matter, leading to fermentation times ranging between 12 and 16 h to reach the concentration of ethanol considered profitable for distillation (10% approximately).