Multiphasic uptake of D-glucose by an oligotrophic marine bacterium

Uptake of D-glucose in the range 2.5 X lOP9 M to 4.0 X I O ~ M by an oligotrophic marine bacterium, LNB-155, could be represented by 4 phases of a single, multiphasic mechanism. Other kinetic models did not give a good fit. Sharp transitions occurred at about 1.6 X 1OV6 M, 10-5 M and 2 X 10-4 M. Values for K, and V,,, increased regularly upon transition to higher phases. Multiphasic uptake mechanisms in LNB-155 indicate adaptation to living in environments with fluctuating levels of D-glucose. These observations are consistent with the hypothesis that pelagic marine bacteria experience considerable fluctuations in nutrient concentration in their microenvironment.