FACTORS AFFECTING THE ACCUMULATION OF BIOTIN BY LACTOBACILLUS ARABINOSUS

Abstract

The results of studies concerned with conditions affecting the uptake of biotin by cells of Lactobacillus arabinosus are presented. Rate studies, including the effects of time, substrate and cell concentration yielded results consistent with those characteristic of enzyme mediated reactions. Sharp temperature and pH optima were exhibited at 37 C and pH 6.8 respectively. Glucose stimulation of biotin accumulation appeared to depend both on the degree of vitamin deficiency and the age of the bacterial cells. The endogenous level of intracellular bound biotin increased as the concentration of biotin in the growth medium was increased. Moreover, the endogenous concentration of bound biotin decreased with increasing age of the bacterial cells. Unexpected were the very high levels of biotin observed in initially biotin deficient cells after incubation with the vitamin under certain conditions. Possible explanations for this finding are offered.