Fermentability Of Saccharomyces cerevisiae (Baker’s Yeast) With Fruit Juices & Carbohydrate substrates

Present study was carried out to know the fermentability of unicellular Baker’s yeast (Saccharomyces cerevisae) with sugar samples & various juices. The standard 20% sugar solutions (such as Glucose, Fructose, Sucrose, Lactose & Starch) were prepared as control. Various plant juices (Sugar cane, Black grapes, Pine apple, Green grapes & Orange.) of 100ml each were prepared by crushing & filtering. Each juice was diluted by adding 400ml of sterilized water. Each of juice sample & sugar solution was inoculated with 8 gms of wet yeast (w/v) under aseptic conditions & other nutrients like ammonium sulphate (NH4)2SO4 were added & the pH is adjusted to 4-5 for proper growth of yeast. All samples were maintained in the incubator at 32°C for 72hrs & were checked for fermentation based on rate of frothing. Based on level of frothing, the amount of ethanol produced & the potential ability of yeast fermentation were determined. It was found that frothing level of samples is not related to quantity production of ethanol. The pH of all fermented samples except in orange juice gradually reduced until 72 hrs of fermentation. Out of all fermented juices, Sugar cane is found to be highest ethanol producing feed stock due to Sucrose content. This is evidenced by results with standard carbohydrate solutions. The glucose is found to be second preferred feed stock for yeast activity followed by Fructose & least with Lactose. The starch has no role in fermentation by yeast. Therefore, composition of fruit juices especially with respect to Sucrose & Glucose play an important role in reduction of inhibitors, & quantity production of ethanol by yeast.