he appearance of a dark purple color within 20 seconds indicates that the organism is oxidase-positive. Oxidase-negative organisms produce either no color to a yellowish color (the original color of the colony) or change to a very light gray color within the 20-second test perio
one drop of H2O2 solution to the culture sample and watch for the production of bubbles in the suspension. These bubbles are the oxygen gas evolved as a result of catalase activity, as the enzyme catalyzes the breakdown of hydrogen peroxide. If no bubbles are produced, the test is negative for the presence of catalase.
"StudyBlue is great for studying. I love the study guides, flashcards and quizzes. So extremely helpful for all of my classes!"Alice , Arizona State University
"I'm a student using StudyBlue, and I can 100% say that it helps me so much. Study materials for almost every subject in school are available in StudyBlue. It is so helpful for my education!"Tim , University of Florida
"StudyBlue provides way more features than other studying apps, and thus allows me to learn very quickly!Â I actually feel much more comfortable taking my exams after I study with this app. It's amazing!"Jennifer , Rutgers University
"I love flashcards but carrying around physical flashcards is cumbersome and simply outdated. StudyBlue is exactly what I was looking for!"Justin , LSU