An Eco-friendly, Scaled-down Gram Stain Protocol

Abstract

Currently, flushing large volumes of Gram stain reagents into sanitary sewage systems is no longer acceptable. These chemical wastes are highly regulated and must be collected, labeled, and disposed of in a responsible manner, usually by paying a commercial service to remove them to an authorized off-site facility. Such services are costly and, as expected, costs are proportional to volume of collected waste. This “old” method of Gram staining, even if effluent is collected, generates a high volume of liquid waste which is unnecessarily diluted with additional large volumes of water from the rinsing steps. The purpose of using this scaled-down and eco-friendly protocol is to dramatically reduce the amount of liquid waste produced without sacrificing quality of results. This protocol is flexible, practical, and easy to implement. It does not require students to work at a bench sink, reduces user cost, and lowers environmental impact overall.