Qualitative Rhodamine B assay which uses tallow as a substrate for lipolytic obligately anaerobic bacteria

A variety of aerobic, lipolytic bacteria and fungi have been studied in detail, due in part to increased industrial demand for lipases. However, few studies have been undertaken on obligately anaerobic lipolytic bacteria as potential sources of lipases. Using a modified version of an agar plate Rhodamine B fluorescence assay, we were able to qualitatively screen obligately anaerobic bacteria from an anaerobic digestor and the rumen of red deer for lipolytic activity towards the neutral lipids olive oil and tallow. Quantitative analysis of tallow from the agar plates inoculated with obligately anaerobic bacteria confirmed that lipolysis had occurred, and in one case, indicated that up to 82.2% of the tallow had been hydrolysed by the lipolytic activity of the bacterial strain. The qualitative tallow-Rhodamine B assay system therefore has potential as a method of screening for obligately anaerobic lipolytic bacteria using solid neutral lipids. (C) 1997 Elsevier Science B.V.