The aim of this experiment was to analyze a sample of finished beer for possible microbiological contaminants such as lactic acid bacteria, Gram-negative bacteria, and wild yeasts/molds. This was accomplished by using a series of spread/pour plate dilutions with various media types that contained selective ingredients. By cross-referencing the different medias and comparing observations, the generalized groups of contaminants were able to be confidently conjectured. Growth was witnessed on DRBC, DRBC + CuSO4, and MRS agars. The finished beer sample was likely contaminated with lactic acid bacteria and wild yeasts such as Brettanomyces sp., based on the colony morphologies witnessed on these respective plates.
Introduction The process of beer fermentation begins with a step called malting, which involves soaking various grains (barley, wheat, etc.) in water, increasing the moisture content of the kernel. The grains are then able to germinate for approximately five days which activates proteases, β-glucanase, α-amylase, and β-amylase. Starches and proteins are then made available for cellular processes such as glycolysis and fermentation. Germination is then halted via a drying process …show more content…
First, glucose is broken down into two 3 carbon molecules of pyruvate through glycolysis which also yields 2 ATP, 2 NADH, and 2 H2O molecules. After which, the enzyme, pyruvate decarboxylase, converts pyruvate to the two-carbon acetaldehyde while also releasing a carbon dioxide molecule. The goal of fermentation (oxidizing NADH back to NAD+) is then accomplished by enzyme alcohol dehydrogenase which uses NADH to reduce acetaldehyde to ethanol. In this process, the energy carries NADH is oxidized and made available for further glycolysis cycles, resulting in the production of the target high energy molecule of adenosine triphosphate
Introduction The process of beer fermentation begins with a step called malting, which involves soaking various grains (barley, wheat, etc.) in water, increasing the moisture content of the kernel. The grains are then able to germinate for approximately five days which activates proteases, β-glucanase, α-amylase, and β-amylase. Starches and proteins are then made available for cellular processes such as glycolysis and fermentation. Germination is then halted via a drying process …show more content…
First, glucose is broken down into two 3 carbon molecules of pyruvate through glycolysis which also yields 2 ATP, 2 NADH, and 2 H2O molecules. After which, the enzyme, pyruvate decarboxylase, converts pyruvate to the two-carbon acetaldehyde while also releasing a carbon dioxide molecule. The goal of fermentation (oxidizing NADH back to NAD+) is then accomplished by enzyme alcohol dehydrogenase which uses NADH to reduce acetaldehyde to ethanol. In this process, the energy carries NADH is oxidized and made available for further glycolysis cycles, resulting in the production of the target high energy molecule of adenosine triphosphate