Peptidoglycan is also part of the membrane component;
hence, a higher amount is normally detected from the cell
wall fraction compared to the intracellular and extracellular
fractions. While peptidoglycan is especially abundant in the
cell wall of Gram-positive bacteria, our results showed that
it was also present in the extracellular and intracellular
fractions of lactobacilli and bifidobacteria. The lower
amounts of intracellular and extracellular peptidoglycan
detected could be due to fragments of peptidoglycan being
released into the medium during cell growth and elongation.
It has been previously stated that peptidoglycan is steadily
broken down by peptidoglycan-cleaving enzymes during
cell growth, especially during the exponential phase, where
a cell wall turnover process occurs, resulting in the release
of peptidoglycan fragments from the wall