Rabiul Haque, Beauty Saha, Chandra Sarkar, Abhiranjan Singh, Soumava Boral, Debasish Pradhan, Susmita Ghatak, Sk Abu Raihan Abdullah, Poulami Dutta, Monomita Sen, Nilak Dutta
Natural vinegar is one of the fermented products which has some potentiality with respect to a nutraceutical standpoint. The present study is an optimization of the fermentation conditions for apple juice vinegar production from aple juice wine, this biochemical process being aided by Acetobacter aceti.We have studied on the development of high yielding alcohol resistant strain of Saccharomyces cerevisiae for the production of alcohol. Overflow metabolism is an undesirable characteristic of aerobic cultures of Saccharomyces cerevisiae during biomassdirected processes. It results from elevated apple juice containing sugar consumption rates that cause a high substrate conversion to ethanol and other bi-products, severely affecting cell physiology, bioprocess performance, and biomass yields. Fed-batch culture, where sucrose consumption rates are controlled by the external addition of sugar aiming at its low concentrations in the fermentor, is the classical bioprocessing alternative to prevent sugar fermentation by yeasts. However, fed-batch fermentations present drawbacks that could be overcome by simpler batch cultures at relatively high initial sugar concentrations From the results it is clear that strain T2. which has been exposed to 15% alcohol for 18 hrs is the high yielding strain, as it gives 16% alcohol after distillation. We also find that as the exposure is increased, that is, with increasing exposure to 20% alcohol for 5 hrs, 18 hrs, and 20 hrs, the production of alcohol decreases. Saccharomyces cerevisiae yeast cells strain T2. which has been exposed to 15% alcohol for 18 hrs were exposed to a homogenous static magnetic field of 125 mT for periods of 24, 48 or 72 hours and then used as inoculum for the alcoholic fermentation. The exposure to the magnetic field improved the fermentation process kinetics. Biomass and ethanol yields of fermentations inoculated with treated inoculum were higher than those in the control fermentation, which was inoculated with an untreated inoculum.
