EXERCISE 10 HYDROLYSIS OF LIPID, STARCH, CASEIN

how do bacteria digest their food

extra-cellularly by means of exoenzymes

what do exoenzymes do

made in the cells and released around the cells where they break nutrient molecules too large to pass through the cell wall allowing for active transport or facilitated diffusion

what hydrolizes starch

amylase by splitting starch molecules into simple sugars

what are lipases

enzymes that cleave lipid molecules into glycerols and fatty acids

what pathogen produces lipases

Staphylococcus aureus

what are proteinases

enzymes that hydrolyze proteins

what is a type of proteinase

caseinase, which hydrolyzes casein

what is the end product of protein hydrolysis

peptides and amino acids

how do you test for amylase production

using agar containing starch, and using iodine to make the starch visible

how do you test for lipase production

using Spirit Blue agar plate containing lipids

how do you test for caseinase production

growing bacteria on agar containing skim milk

what does positive and negative amylase results look like

positive: areas hydrolyzed will be clear (orange/yellow)

negative: areas where starch remains undigested will be dark (purple black color)

what does positive and negative lipase results look like

positive: cleared zones

negative: prob still blue idk

what does positive and negative caseinase results look like

positive: clear transparent zones

negative: looks like milk

what does it mean if you see areas with dark blue precipitate around cleared zones in lipase test

Spirit Blue and free fatty acids interacted, and fatty acids will be broken down eventually which would make blue precipitate dissapear