Problems with toluene and the determination of extracellular enzyme activity in soils

Six of 7 fungi imperfecti, 7 of 13 basidiomycetes, and 6 of 14 bacteria tested were able to grow with 0.1 or 0.05% toluene as a sole source of carbon indicating an invalid use of toluene as a biostatic agent for analysis of extracellular enzymes in soil. Analysis of laccase and peroxidase activities in soil under controlled laboratory conditions revealed significant variability, indicating even greater difficulty in evaluating these soil enzyme activities under natural conditions.