Production of medical-grade biopolymer in air lift bioreactors.

Microbes are known to produce biopolymers for societal applications. Economical production of biopolymer (PHB) is desperately required to significantly replace or reduce usage of non-degradable polypropylene produced by disappearing petroleum resources. Besides it is also equally important to ensure abundant availability of low cost medical grade biopolymers which can be used for several medical applications in society. It has been invariably observed that mechanical agitation in the bioreactors features major power consumption in the operation of bioreactors therefore usage of air lift bioreactors are likely to reduce power consumption by mechanical agitation significantly thereby leading to economic biopolymer production. Present investigation evaluates the possible role of pneumatic bioreactors (e.g., Bubble Column, Outer Aeration Inner Settling, Inner Aeration Outer Settling) as alternates to mechanically agitated bioreactors for the economic production of medical grade biopolymers P(3HB) by Bacillus thuringiensis IAM12077 using glycerol and glucose as major substrates. It was observed that Bacillus thuringiensis IAM12077 cultivations featured Biopolymer P(3HB) accumulations of 22.48%, 37.07%, 27.73%, in BC, OAIS, IAOS air lift bioreactors. Relatively higher product yield, volumetric productivity and P(3HB) accumulation was observed in Outer Aeration Inner Settling (OAIS) air lift bioreactor configuration as opposed to other pneumatic bioreactors.