Carboxyl groups have an electronegative oxygen atom double bonded to a carbon atom. This carbon-oxygen bond is very polar and the fact that its a double bond increases the polarity of the bond.
PEA agar, also referred to as Phenylethyl Alcohol Agar is a medium  used by microbiologists to grow microorganisms. The ingredient that  supplies nitrogen is casein. Making the world better, one answer at a time.
Pour your thin pea-cell soup through a strainer into another container (like a measuring cup). Add 2 tablespoons liquid detergent (about 30ml) and swirl to mix. Let the mixture sit for 5-10 minutes. Pour the mixture into test tubes or other small glass containers, each about 1/3 full.