Open AccessIsolation and characterization of the N 2 ‐fixing marine photosynthetic bacterium Rhodopseudomonas marina , variety agilis
Author(s) -
Mangels Lori A.,
Favinger Jeffrey L.,
Madigan Michael T.,
Gest Howard
Publication year - 1986
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1986.tb01675.x
Subject(s) - anoxygenic photosynthesis , phototroph , botany , biology , nitrogenase , photosynthesis , rhodopseudomonas , bacteria , purple bacteria , chemistry , nitrogen fixation , genetics , photosynthetic reaction centre
Rhodopseudomonas marina/agilis was enriched from a natural microbial mat by using conditions that favor growth of anoxygenic photoheterotrophs able to fix N 2 rapidly. The isolated bacterium grows more readily on fructose or mannitol than on organic acid carbon sources, requires preformed biotin and thiamine as growth factors, and is extraordinarily motile; growth occurs up to a temperature of approx. 44°C. The photosynthetic pigments of R. marina/agilis are housed in intracytoplasmic lamellar membranes which show the in vivo absorbance characteristics of bacteriochlorophyll a and carotenoids of the normal spirilloxanthin series. In common with other non‐sulfur purple bacteria, R. marina/agilis can also grow as an aerobic heterotroph in darkness. Under these conditions, photopigment synthesis is severely repressed. R. marina/agilis requires 1–5% NaCl for optimal growth, and cells grown on N 2 showed nitrogenase activity of >1000 nmol acetylene reduced h/mg dry wt.