Light-Stimultated Aerobic Growth of <italic>Erythrobacter</italic> Species OCh 114

Abstract

Bright light almost completely suppressed bacteriochlorophyll synthesis in Erythrobacter species OCh 114. Consequently, the effect of continuous illumination on growth was barely observed when illumination was started an inoculation and the inoculum size was small. However, when an aerobic culture of this bacterium grown preliminarily in the dark was illuminated after the cell density became high, light stimulated the growth remarkably, indicating that the utilization of light energy for growth via bacteriochlorophyll which had been formed during the growth in the dark. The maximum cell yield from a culture intensely illuminated following preliminary growth in the dark was twofold that from a culture grown in the dark throughout. A continuous oxygen supply was a prerequisite for the stimulation of growth by light. Microaerobic or anaerobic incubation of a dark-grown culture in the light brought about a decrease in spheroidenone content and a formation of an unknown pigment.