The ingredient in phenylethyl alcohol agar that supplies nitrogen is peptone. Peptone is a protein digest that provides essential amino acids and nitrogen sources for the growth of certain bacteria. This makes it a crucial component for supporting the growth of organisms while inhibiting the growth of gram-negative bacteria in the medium.
Enterococcus faecalis typically does not grow on MacConkey agar as this selective and differential medium is primarily used for isolating and differentiating members of the Enterobacteriaceae family, which are mostly gram-negative bacteria. Enterococcus species are gram-positive bacteria and do not ferment lactose, the key ingredient in MacConkey agar that allows for differentiation.
Lac+ bacteria is acid base color indicator that lowers the pH of the MacConkey agar. The MacConkey agar contains neutral red dye, lactose, peptone, and crystal violet dye.
MacConkey agar is designed to grow Gram-negative bacteria and also contains crystal violet dye which inhibits the growth of Gram-positive bacteria. Since S. aureus is Gram-positive it should not grow on MacConkey agar. No. MacConkey agar inhibits MOST of the Gram-positive bacteria. There are some Gram-positive bacteria that can tolerate bile-salt are able to grow in MacConkey agar. Enterococcus and some species of Staphylococcus are able to grow in MacConkey. (lack citation though)
Clostridium species do not grow on MacConkey agar because they are anaerobic bacteria that require an oxygen-free environment, while MacConkey agar is designed for the growth of aerobic and facultatively anaerobic Gram-negative bacteria. Additionally, MacConkey agar is selective for lactose fermenters, and Clostridium does not ferment lactose. Therefore, Clostridium cannot be cultured on this medium.
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.
mannitol is a type of sugar, so it supplies the carbon in the MSA medium
Enterococcus faecalis typically does not grow on MacConkey agar as this selective and differential medium is primarily used for isolating and differentiating members of the Enterobacteriaceae family, which are mostly gram-negative bacteria. Enterococcus species are gram-positive bacteria and do not ferment lactose, the key ingredient in MacConkey agar that allows for differentiation.
No, Alcaligenes faecalis will not grow on MacConkey agar. MacConkey agar is selective for gram-negative bacteria that ferment lactose. Alcaligenes faecalis is a gram-negative bacteria that does not ferment lactose, so it will not grow on MacConkey agar.
Peptone in phenylethyl alcohol agar supplies both carbon and nitrogen to support the growth of microorganisms. Peptone is a mixture of partially digested proteins that serve as a nutrient source for microbial growth.
Casein is the ingredient in PEA that supplies carbon, as well as nitrogen. PEA is also known as Phenylethyl Alcohol Blood Agar.
Undefined.
MacConkey agar
Lac+ bacteria is acid base color indicator that lowers the pH of the MacConkey agar. The MacConkey agar contains neutral red dye, lactose, peptone, and crystal violet dye.
mannitol is a type of sugar, so it supplies the carbon in the MSA medium
MacConkey agar contains agar as a solidifying agent which solidifies at room temperature to provide a solid surface for bacterial growth and colony isolation. MacConkey broth, on the other hand, does not contain agar and remains liquid at room temperature to allow for easier culture of bacteria in liquid medium for metabolic studies or growth analyses.
MacConkey agar is designed to grow Gram-negative bacteria and also contains crystal violet dye which inhibits the growth of Gram-positive bacteria. Since S. aureus is Gram-positive it should not grow on MacConkey agar. No. MacConkey agar inhibits MOST of the Gram-positive bacteria. There are some Gram-positive bacteria that can tolerate bile-salt are able to grow in MacConkey agar. Enterococcus and some species of Staphylococcus are able to grow in MacConkey. (lack citation though)