Preliminary evaluation of biopolymers production by mixed microbial culture from citrus wastewater in a MBR system using respirometric techniques

Abstract

This preliminary study was aimed at evaluating the feasibility to produce biopolymers (BP) from citrus wastewater by mixed microbial culture in an anaerobic/aerobic membrane bioreactor (A/O-MBR). The activated sludge of the A/O-MBR was successfully enriched in microorganisms having a good capacity in producing intracellular biopolymers. The production of BP was found to be about 0.55 mgCOD mgCOD−1 using pure acetate at a concentration of 1000 mgCOD L−1. When using fermented wastewater, the conversion of acetate into BP product was 0.56 mgCOD mgCOD−1 in the test performed with C/N equal to 1000:1, whereas it was only 0.12 mgCOD mgCOD−1 in the test with C/N of 100:5. The results achieved suggested the feasibility to use citrus wastewater as a feedstock for biopolymers production although the low biomass storage capacity (0.26 mgCOD mgCODbiomass−1) suggested the need for optimizing the operating conditions in future studies.