MLT1 Task 5 Essay Example | Topics and Well Written Essays - 250 words

MLT1 Task 5 - Essay Example Streptococci lacti) and Lactobacilli (e.g. Lactobacillus casei, L. pentosus), which produce lactic acid as the end product of fermentation (Buchanan & Cibbons, 1974). Other glucose fermenting bacteria that produce these acids are Proteus, Shigella, Salmonella, Escherichia coli, Microbacterium and Leuconostoc (Buchanan & Cibbons, 1974). When using phenol red indicator in the broth media, two bacterias that ferment glucose were the E. coli and Shigella sonnei, they produced measurable acid by-product because the broth media changed from red to yellow. Therefore, organisms like Escherichia coli, ferments glucose through fermentation thereby liberating large amount of three types of acids like succinic, lactic, and acetic, which changes the media from yellow to red (McDevitt, 2009). The Voges – Proskauer test is appropriate because of the detection capability of acetoin, which is produced by the bacteria that use it as metabolic intermediate by following the butane diol pathway (Buchanan & Cibbons, 1974). This test is used when differentiating Escherichia coli from other Enterobacter  species like Enterobacter  aerogenes because E. coli is positive in Methyl red yet negative Voges-Proskauer whiles the Enterobacter  aerogenes is negative in Methyl red test and positive in Voges-Proskauer (McDevitt, 2009). Availability of main source of food determines the enzymes and the pathway of glucose metabolism because different nutrients require specific enzymes hence determining the pathway (Dannessa, 2014). However, alternative pathways are used when organism require a specific amount of ATP, since different pathway produce a certain amount of ATP after oxidation of glucose (Dannessa,