ABSTRACTWhen a salt marsh isolate ofA. pullulanswas grown under all combinations of three different hydrogen ion concentrations, two levels of inoculum density, and three agitation rates, both first- and second-order interactions occurred which affected the percentage of mycelial development as well as mycelial and yeast cell biomass production. Although these interactions indicate that the effect of a single environmental factor on development depends on the level of the other interacting factors, certain trends associated with individual factors were evident. Low agitation favored mycelial development both on a percentage and a dry weight basis while high agitation favored production of yeast cells. High inoculum density tended to promote production of mycelium, whereas a pH of 7.5 inhibited yeast cells.