EXERCISE 14: REPORT
EXTRACELLULAR ENZYMES
Proteins
Starch Hydrolysis
1. Flood the starch agar plate with the lodine solution, allow the iodine to remain
in contact with the medium for 30 seconds, and pour off the excess.
2. Examine the cultures for the presence or absence of a blue-black color surrounding
the growth of each test organism.
Bacterial species
E. coli
P. fluorescens
B. subtilis
Describe the Appearance of
the medium around the cells
donc around the w we
made
has clearing, has no doniness
oround the w
Dark brown
Result (+ or -) for
Starch Hydrolysis by
Polysaccharidases
-
+
-
Milk Casein Hydrolysis
Examine the milk agar plate cultures for the presence or absence of a clear area, or zone of
proteolysis, surrounding the growth of each test organism.
Bacterial species
E. coli
P. fluorescens
B. subtilis
Describe the Appearance of
the medium around the cells
has no cleanny, has over
growth
yellow color around the w
over growth
Result (+ or -) for
Casein Hydrolysis
by Proteases
-
-
-