Bioprocess for the simultaneous production of polyhydroxybutyrate and violacein pigment from himalayan bacterium iodobacter sp. PCH 194

A bioprocess for the simultaneous production of polyhydroxybutyrate (PHB) and violet-blue violacein pigment using the isolated bacterial strain of Iodobacter sp. MTCC 25171, the process comprising the steps:

• i) inoculating a loopful of Iodobacter sp. MTCC 25171 in 50 mL sterile nutrient broth medium and incubating at a temperature of 20±2° C. for 32 to 36 hours, at 100 to 200 rpm to obtain a seed culture for inoculating the production medium;
• ii) inoculating 3 to 5% v/v of the seed culture as obtained in step [i] to a sterile production medium and incubating for 36 to 100 hours at 100 to 200 rpm at a temperature of 20±2° C. to obtain a biomass;
• iii) harvesting the biomass as obtained in step [ii] to obtain a pigmented cell pellet by centrifugation or microfiltration;
• iv) suspending the pigmented cell pellet as obtained in step [iii] in methanol or ethanol, in a volume ratio of 1:3 to 1:5 and mixing well for 10 to 15 minutes at room temperature followed by centrifugation to obtain a pigment in the supernatant;
• and repeating the step until no visible violet colour remains in the cell pellet to obtain a colourless cell pellet;
• v) concentrating the supernatant as obtained in step [iv] using vacuum evaporation to obtain the desired violacein pigment;
• vi) suspending the colourless cell pellet as obtained in step [iv] in 3 to 5 times the volume of 1:1 trichloromethane and bleaching solution, followed by incubating overnight at temperature ranging from 30 to 40° C. under continuous shaking to obtain a mixture;
• vii) allowing the mixture as obtained in step [vi] to stand for 10 to 15 minutes and pipetting out the lower organic layer in a test-tube and then adding 3 to 5 times the volume of chilled methanol, followed by mixing it well and keeping at temperature ranging from minus 4 to minus 20° C. for 30 to 60 minutes for precipitation to obtain a reaction mixture;
• viii) centrifuging the reaction mixture as obtained in step [vii] to collect the pellet as precipitate and removing the residual solvent;
• ix) drying the pellet as obtained in step [viii] and re-dissolving it in trichloromethane;
• and
• x) repeating steps vi to viii and finally collecting the pellet of Polyhydroxybutyrate by allowing the residual solvent to evaporate.