A material recovery process from wastewater using photosynthetic bacteria was
introduced in this paper. Photoheterotrophic growth of photosynthetic purple
nonsulfur bacteria results in high conversion rates of dissolved organic matter into
their cell materials, such as protein and PHA (polyhydroxyalkanoate), which can be
utilized for agricultural and industrial uses.
Growth rates and PHA accumulation performances of Rhodobacter sphaeroides were
determined under various conditions (substrate, temperature, light intensity and
sulfide concentration). Optimal light intensity and temperature were shown to be
>6000 lx and 25-35~ respectively. Acetate was preferable for the growth and PHB
production, while propionate gave no accumulation of PHB (Poly-3-
hydroxybutyrate). The growth of R. sphaeroides was sensitive to sulfide, but this
problem of growth inhibition could be alleviated by adding purple sulfur bacteria
Chromatium vinosum.