Impact of oxygen limitation on glycerol-based biopolymer production by bacterial enrichments

The increasing production of bioethanol and biodiesel has resulted in the generation of a massive amount of crude glycerol, inducing the need for effective valorization of these waste streams. One of the valorization options could be through conversion of crude glycerol into a biopolymer using microbial community engineering in a feast-famine process. A complicating factor in the production of biopolymers from glycerol encountered in previous works is that two different types of polymers can be formed; polyhydroxyalkanoate (PHA) and polyglucose. Here we describe the effect of limiting the oxygen supply rate on the polymer distribution with the aim of defining the conditions that favour the conversion of glycerol in one single polymer. The decrease of oxygen supply rate during the biopolymer maximization step did not influence glycerol partitioning among PHA and polyglucose, but oxygen limitation during the community enrichment step favoured polyglucose storage over PHA.