Starch contains high levels of amylose and amylopectin and has good biodegradability, making it an attractive alternative biopolymer raw material and is considered to have important commercial value because of its various industrial applications. In this study, bifunctional gadung starch is used to manufacture bioplastics and for photocatalyst wastewater degradation. The use of gadung starch as a photocatalyst was investigated by comparing two temperature variations, i.e., 150 °C and 200 °C. The results of the analysis showed that heat treatment of starch at 200 °C could degrade nitrophenol waste by up to 66.66 %. Bioplastics produced with three times higher starch concentration than other samples have a good mechanical property, i.e., a tensile strength of 21.61 MPa and a degradation percentage of 90 %. The use of gadung starch for bifunctional purposes: photocatalyst and bioplastics is a new development in research in recent years.