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Decrease in seasonal rainfall is threat to aquatic life including bacteria. Mesophilic aerobic bacteria in
aquatic bodies are easy to cultivate in laboratory than anaerobic bacteria. Cultivation of anaerobic
bacteria requiring light demands careful protocols and appropriate nutrients. Present work deals with
this unique group referred to as anoxygenic photoheterotrophic bacteria from Wadali Lake, Amravati,
Maharashtra, India. These bacteria were cultivated on mineral salt succinate agar in anaerobic gaspac
jar exposed to light of 2400 lux for 8-10 days. Of the twenty isolates extracted from these lakes ten
bacteria were further fully characterized based on their abilities to produce polyhydroxy butyrate (PHB).
PHB was extracted from these bacteria and was detected spectrophotometrically. The efficient PHB
producing genera belongs to Rhodobacter, Rhodopseudomonas and Rhodospirillum. This work was
further extended to isolation and characterization of rhodopsin which is a characteristic pigment of
anoxygenic phototrophic bacteria. This pigment has wide range of application most significant being
artificial retina preparation. After extraction of this photosynthetic pigment, comparative studies were
carried where this pigment was found in higher quantities in Rhodopseudomonas culture broth which
suggest the suitability of this culture for rhodopsin extraction. Though rhodopsin is found in wide range
of fungi, animals and bacteria but latter group is preferable with regards to ease in isolation of the
pigment. Regarding PHB production, the highest levels of PHB were found in Rhodobacter species. The
production of both PHB and rhodopsin from photoheterotrophic bacteria are economical processes as
the energy source of these bacteria is light.
Keywords: Anoxygenic; PHB; photoheterotrophs; production; rhodopsin.