University:
Swansea University
Course:
PM134 | Microbiology
Academic year:

2023
Views:

233

Pages:

2
Author:

Amal J.

Lactic Acid BacteriaLAB - gram tve, Non spore forming rods/cocci- Most are aerotolerant anaerobes which lack cytochromes andporphyrine- Catalase & oxidase -ve- Some take up O2 through medication of flavoprotes oxidasesand is used to produce H2O2 / to reoxidize NaDH producedduring the dehydrogenation of sugarsGroup has 13 genera of gram +ve bateria.CarnobautoriumDenococcusEnterococcuspediococausLactococcusparalactobauillusLautobavillueStreptococusLactosphaeraTetragenococousLeuroconostaVagowousWeisellaClassifilation-Cellular energy is derived from the formentation of Carbohydratto produce principally lautic and TO do the / they use one oftwo diff. pathways and this provide a useful diagnosticfeature in their classificationHomeformentors - Produce lautase as virtually a single pdt frthe formantation of glueose They follow the Emden - -MeyerParnas (EMP) glycolytic pathway whereby the 6 -C molecule glucose is phosphorylocked and Tsomorized before. leavage bythe enzymee aldolace into glyceraldehyde. - 3 phosphate Thisis then converted to pyruvate during which ATP is producedby Substrate- - level phosphorylation at two sites to give an overallyield of 2 molecules of ATP for every molecule of glucose order formantedIn order to regenerate the NAD1 consumed in the to ofglyceraldehyde -3 phosphate pynivate is reduced loutateusing NADH.HeteroformentorsHeteroformenture produce roughly equimolar amounts of lactate,ethanol / acetate and carbon dioxide from glucoseintoThey lack aldolase and transform the hexore, glucose, apentose by a sequence involving oxdn and decarboxylation.The pentre is leaved into glyceraldehyda phosphate and acetylphosphate by the enzyme phosphoketolase.The triox phosphale is converted into lactate by the same sequenceof reans as occurs in glycolysis to give two molecules ofATP.The fate of the acety phosphate depends on the e acceptorsavailable, in the absence of alternative acetyl phosphatefuyis this role and is reduced to ethanol while regeneratingtwo molecules of NAD1 and NADH.