Abstract
Absorption curves have been obtained in the spectral region of 450 to 900 mmicro for the water soluble cell juice of four species of photosynthetic bacteria, Spirillum rubrum (strain S1), Rhodovibrio sp. (strain Gaffron), Phaeomonas sp. (strain Delft), and Streptococcus varians (strains C11 and orig.). These curves all show maxima at 790 and 590 mmicro due to bacteriochlorophyll, whose highest band, however, occurs at 875, 855, or 840 mmicro depending on the species. The bacteria that appear red rather than brown have a band at 550 mmicro due to a carotinoid pigment. An absolute absorption curve of bacteriophaeophytin has maxima at 530 and 750 mmicro. The extraction of cell juice by supersonic vibration does not change the position of the absorption bands or of the light absorbing capacity of the pigment.