Respiratory activity, molar growth yields, and ATP content in an Arthrobacter sp. ammonium-limited chemostat culture

Abstract

Arthrobacter fluorescens was grown in chemostat culture under ammonium-limited conditions and respiratory activity; molar growth yields and ATP content were determined over a wide range of dilution rates. Within a range of dilution rates between 0.10 h−1 and 0.20 h−1, morphological transition occurred, the ratio of cocci to rods appearing inversely related to growth rate. Molar growth yields for both glucose and ammonium decreased with increasing dilution rates because of the higher intracellular polysaccharide content at the lower growth rates. Different metabolic activities were shown in cocci, in rods, and during morphogenesis. A sharp decrease in in situ and potential oxygen quotient (Q(O2)) and in ATP content was observed in the range of dilution rates in which morphological changes occurred.