Over reliance on energy or petroleum products has raised concerns both in regards to the depletion of their associated natural resources as well as their increasing costs. Bioplastics derived from microbes are emerging as promising alternatives to fossil fuel derived petroleum plastics. The development of a simple and eco-friendly strategy for bioplastic production with high productivity and yield, which is produced in a cost effective manner utilising abundantly available renewable carbon sources, would have the potential to result in an inexhaustible global energy source. Here we report the biosynthesis of bioplastic polyhydroxyalkanoates (PHAs) in pure cultures of marine bacterium, <
i>
Saccharophagus degradans<
/i>
2-40 (<
i>
Sde<
/i>
2-40), its contaminant, <
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Bacillus<
/i>
cereus, and a co-culture of these bacteria (<
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Sde<
/i>
2-40 and <
i>
B. cereus<
/i>
) degrading plant and algae derived complex polysaccharides. <
i>
Sde<
/i>
2-40 degraded the complex polysaccharides agarose and xylan as sole carbon sources for biosynthesis of PHAs. The ability of <
i>
Sde<
/i>
2-40 to degrade agarose increased after co-culturing with <
i>
B. cereus<
/i>
. The association of <
i>
Sde<
/i>
2-40 with <
i>
B. cereus<
/i>
resulted in increased cell growth and higher PHA production (34.5% of dry cell weight) from xylan as a carbon source in comparison to <
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Sde<
/i>
2-40 alone (22.7% of dry cell weight). Lastly, the present study offers an innovative prototype for production of PHA through consolidated bioprocessing of complex carbon sources by pure and co-culture of microorganisms.