In Gram staining, the outer membrane is removed by an alcohol solution, which also decolorizes the then exposed peptidoglycan layer by disolving away the previuosly applied crystal violet.
In Gram staining, the outer lipid-based membrane of Gram-negative bacteria is removed by an alcohol solution. The alcohol also decolorizes the then exposed peptidoglycan layer by disolving away the previuosly applied crystal violet.