Fermentation products (Biomass)

Principle Fermentation: it is a metabolic process that converts complex organic compounds (ex: sugars) into simpler ones along with other products ( ex: gases as CO2). Fermentation also produces ENERGY which is important for the growth process. Microbial growth evaluation: it is done by linking the product production or BIOMASS formaton with the substrate use.

Yeast ferment sugar ( GLUCOSE) aerobically Baker’s yeast + ethanol + CO 2 To produce

Experiment #1: Materials Fresh culture of Saccharomyces cervisiae (yeast) grown on glucose yeast extract peptone agar (GYEP agar). 250 ml Flasks containing 100 ml glucose yeast extract peptone broth. Glucose strips and glucose detection device. Graph paper.

Experiment #1: Procedure Day 1: Using a sterile loop inoculate the GYEP broth flasks with 1 or 2 colonies of yeast grown on the GYEP agar plate. Aseptically remove 3 ml of broth so that the initial yeast population is estimated by measuring optical density (OD) at 600nm using a colorimeter. To measure the glucose content, use diabetic glucose test strip and glucose detection device. Record your results as the zero time readings. Incubate flasks at 30 0 C in an incubator shaker adjusted at 150 rpm.

Day 2 Samples should be taken at time intervals 6, 12 and 24 hours. Measure the optical density (OD) and glucose level for each sample. Plot a graph showing the change in biomass and glucose content over time intervals.

Experiment #2: Determination of CO 2 Produced during Glucose Fermentation Add 10 ml Distilled Water Add 10 ml 1% Glucose Solution cT

Experiment #2: Determination of CO 2 Produced during Glucose Fermentation Add 5 ml Yeast Extract cT

Experiment #2: Determination of CO 2 Produced during Glucose Fermentation cT Measure Initial Height of Air Space After Inversion Place in Water Bath at 40°C and remove after 7 min and remeasure the heights of the air spaces. Place again in the water bath and redo this step after 15 min.

Experiment #2: Determination of CO 2 Produced during Glucose Fermentation cT Falcon Tube (TEST) shows a greater volume of air space than falcon tube (CONTROL) due to CO 2 production from fermentation of glucose.