Lab 23: Decarboxylation of Amino Acids

Question 1

this tests for

Answer 1

the ability to decarboxylate (remove carboxyl group from molecule) amino acids to differentiate members of the Enterobacteriaceae
-lysine ,arginine and orthinine are amino acids used to differentiate

Question 2

decarboxylation broth contains

Answer 2

one amino acid and pH indicator bromcresol purple
-purple = alkaline conditions
-yellow = acidic conditions
-sterile mineral oil is added to create anaerobic environment for decarboxylation to occur

Question 3

what are the byproducts if decarboxylation?

Answer 3

alkaline
-if reaction occurs, will stay purple/deeper purple or red
-no reaction = yellow or clear = no decarboxylation

Question 4

K. pneumoniae results

Answer 4

lysine = yes amino acids were decarboxylated
arginine = no
ornithine = no

Question 5

P. vulgaris

Answer 5

lysine= no decarboxylation
arginine= no
ornithine=no

Question 6

E. aerogenes

Answer 6

lysine= yes
arginine= no
ornithine=yes

Question 7

E. cloacae

Answer 7

lysine=no
arginine=yes
ornithine=yes