BIOS 242 Week 3 Lab 2; Carbohydrate Fermentation

Lab6:CarbohydrateFermentation LearningObjectives: • Definefermentationanddevelopaknowledgeoffermentationendproducts. • Understandthetheorybehindthecarbohydratefermentationprocedure. • Understandthevariouscomponentsofthecarbohydratemediaandhowthesecomponents work. • Appropriatelyanalyzeresultsforavarietyofmicroorganisms. Intheclinicallaboratory,onetechniqueusedtoidentifybacteriaisthecarbohydratefermentationtests.Bacteriahavetheabilitytoutilizedifferenttypesofcarbohydrates;ifthebacteriapossessthenecessaryenzymes to break down those carbohydrates; they will produce acidic end-products and in some casesCO2 gas. In this laboratory, we will determine the carbohydrate fermentation profiles of differentbacteria. Materials:PhenolredandDurhamtubecontainingdextroseandsucrosemedia,inoculatingloops,incinerators,culturesofS.epidermidis,E.coli,S.marcescens,and B.subtilis Method: 1. Studentswilldothisexperimentingroupsof4. 2. Obtain4tubesofDextroseorSucrosetubescontainingphenolredpHindicatorandDurhamtubepergroup. 3. Labeleachtubewitheachofthebacterialistedinthematerialssection. 4. Inoculateeachtubewiththeappropriatebacteriausingaseptictechniques. 5. Incubateeachtubeat37 ◦Cfor18-24hours. 6. Keepthetubesclosedandmakeobservationsusingclosedtubesonly. 7. Readandrecordyourobservationsinthelabreport. 8. Getresultsfromothergroupsinyourclassfortheothermediaandrecordtheobservationsinthelab report andcomplete the report. 9. InthetableintheResultssection,“A”representsacidicend-products,“+”representsgasformation,and “-“representsnochange. LabReport: Purpose:Pleasedescribeincompletesentencesandinyourownwords,thepurposeofthisexperiment. The purpose of this experiment was to be able to use a technique that is used to identify bacteriathrough a fermentation test. Different carbohydrates are used, after inoculation we incubate the testtubes.Thisismeanttotelluswhetherthebacteriahastheenzymestobreakdownthecarbohydrates,ifitdoesthen the productswillbeacidic. Results: Questions: 1) Whatisthepurposeofthetrypticaseinthebrothandwhyisthisimportant?Bespecific. 2) Pleasedescribethefermentationprofileofthebacteriausedintheprocedure. 3) Ifthemediaisorangeinsteadofyellow,thetubeshouldbeincubatedanadditional24hours.Pleaseexplain whythe additionalincubation isneeded. 4) YouinoculateaDextrosebrothwithanorganismsknowntofermentdextrose.After18-24hours,thereisnochangeinthebroth.Pleaseexplainatleasttwopossibilitiesforthelackofresults.