ATTACHED GROWTH FUNGAL SYSTEM FOR FOOD PROCESSING WASTEWATER TREATMENT AND HIGH VALUE PROTEIN RECOVERY

Organic removal and high value fungal biomass production from food (corn) processing wastewaters for an attached growth fungal system under non-aseptic conditions were evaluated. Plastic composite support (PCS) tubes, composed of 50% (w/w) polypropylene and 50% (w/w) agricultural products were used as biofilm support media to grow a pure culture of Rhizopus oligosporus. Biofilm formation on the support media was controlled by agitation speed. Without nutrient supplementation, biomass production of 0.32 g volatile suspended solids (VSS)/g chemical oxygen demand (COD)removed with fungal protein content of 34% (w/w) was obtained. With nutrient supplementation, COD removal improved significantly to 85% with a high biomass production of 0.56 gVSS/gCODremoved and protein content of 37% (w/w). Maximum COD removal and biomass production was achieved at pH 4.0 with minimal bacterial competition. The fungal protein contents for operating pH of 3.5, 4.0 and 4.5 were nearly constant at 31, 36 and 33% (w/w), respectively. The wastewater composition proved to have significant effect on the biofilm reactor performance. Thus, the attached growth fungal system was able to convert corn processing wastewater into high value protein biomass.