Nitrogenase and photosynthetic activities of chemostat cultures of Rhodobacter capsulatus 37b4 grown under different illuminations

• Published in: Archives of microbiology Vol. 152; no. 1; pp. 100 - 104
• Main Authors: STEINBORN, B, OELZE, J
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-06-1989; Berlin
• Subjects: Biological and medical sciences; Cell structures and functions; Chloroplast, photosynthetic membrane and photosynthesis; Fundamental and applied biological sciences. Psychology; Molecular and cellular biology; Characterization; Light effect; Rhodobacter capsulatus; Rhodospirillales; Enzymatic activity; Nitrogenase; Nitrogen fixation; Bacteria; Environmental factor; Rhodospirillaceae; Photosynthesis
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/BF00447019

Nitrogen fixation as well as structural and functional properties of the photosynthetic apparatus were studied with phototrophically grown chemostat cultures of Rhodobacter capsulatus strain 37b4. Illumination was varied between 3,000 and 30,000 lx at a constant dilution rate of D = 0.075 h super(-1). Steady state parameters of growth revealed two forms of limitation, i.e. energy limitation in the range of 3,000 to about 10,000 lx and nitrogen limitation at higher illuminations. In spite of the apparent constancy of the composition and activity of the photosynthetic apparatus under energy limitation, maximal specific acetylene reduction and hydrogen evolution activities increased by factors of 3 and 8, respectively, when illumination of the culture was raised from 3,000 to about 15,000 lx. Above 15,000 lx, both activities of nitrogenase approached constancy.