Reversal of the inhibitory effect of surfactants upon germination and growth of a consortium of two strains of Bacillus

Anionic, cationic, amphoteric and non-ionic surfactants inhibited spore ger mination and subsequent growth of a mixture of two Bacillus strains at surf actant concentrations ranging from 1 ppm to 50 ppm. Germination appeared to be more affected than cell growth by the presence of surfactants, the inhi bitory thresholds being largely increased when media were inoculated with v egetative cells. The bacterial species forming the consortium were incapabl e of growing on liquid and agar-solidified media prepared with non-diluted domestic wastewater. Addition of hydrolases (protease, cellulase, alpha-amy lase and lipase) to the wastewater medium allowed the germination of spores and their vegetative growth.