Production of PHA from Cassava Starch Wastewater in Sequencing Batch Reactor Treatment System

The project attempt to investigate the potential of cassava starch wastewater for producing polyhydroxyalkanoate (PHA) from sequencing batch reactor (SBR) treatment system seeded with Bacillus tequilensis MSU 112, a PHA-producing bacterial strain. A total sequence of 24 h with a reaction phase (22 h) comprised anoxic/aerobic steps of 4/18 h was employed. The effect of varies chemical oxygen demand (COD) concentration of the synthetic cassava starch wastewater (CSW) (3,000 4,000 and 5,000 mg/L) on PHA production and treatment efficiency was determined. The CSW with COD at a concentration of 4,000 mg/L produced the highest PHA concentration, PHA yield, and total kjeldahl nitrogen and total phosphate removal efficiencies at 3,346 mg/L, 79.2% as dry sludge weight, 20.6% and 27.7%, respectively, while the CSW with COD concentration of 5,000 mg/L provided the highest COD removal efficiency at 94.8%. In addition, the activated sludges obtained from an anoxic phase provided higher PHA production than an aerobic phase. The results revealed that the SBR system treating CSW with the presence of B. tequilensis MSU 112 offers a promising approach for PHA production.