Considerable interest in the development of biobased polymers is being garnered due to their diverse
applications and biodegradability. In this communication, bioplastics (as polyhydroxyalkanoates) production
using wastewater as a substrate was studied by varying the reactor microenvironment (aerobic
and microaerophilic) and operating pH (6, 7 and 8). Redox reactions occurring in the mixed culture
during polyhydroxyalkanoates production were investigated. Maximum polyhydroxyalkanoates production
in terms of dry cell weight (%) was observed in microaerophilic operation (56%), compared to
aerobic (34%) operation. Neutral pH showed better polyhydroxyalkanoates synthesis (56%) than basic
(44%) and acidic (28%) redox microenvironments. Neutral pH operation documented higher dehydrogenase
enzyme activity, reduction currents, substrate degradation than acidic and alkaline pH at
microaerophilic environment that correlated well with higher polyhydroxyalkanoates production.
Biopolymer composition showed the presence of co-polymer, poly-(3-hydroxybutyrate-co-3-
hydroxyvalerate). Fluorescence in situ hybridization analysis revealed the presence of phylum Proteobacteria,
Acidobacteria and Firmicutes in mixed culture which are known for polyhydroxyalkanoate
production. This study illustrated that efficient utilization of wastewater for bioplastics production at
optimum conditions can be viewed as viable solution for tackling the problems of increasing waste
advocating the concept of ‘waste to wealt