The presence of clear halos surrounding colonies is positive for their ability to digest the starch and indicates the presence of alpha-amylase. The final step in the chain may involve the use of the ...The presence of clear halos surrounding colonies is positive for their ability to digest the starch and indicates the presence of alpha-amylase. The final step in the chain may involve the use of the enzyme cytochrome oxidase, which catalyzes the oxidation of cytochrome c while reducing oxygen to form water. How did the results observed on the MSA and EMB agar correlate to the Gram reaction of the bacteria?
