Biodegradable and renewable bioplastics have the potential to play a crucial role in the bioeconomy. In this study, we extract protein from tofu dregs and use formaldehyde (HCHO) as a strengthening agent. We employ the casting method to manufacture the bioplastics. These bioplastics are then characterized using X-ray diffraction (XRD) to analyze crystal structure, Fourier-transform infrared spectroscopy (FTIR) to identify chemical bonding of functional groups, tensile strength tests to determine mechanical properties, and degradation tests in seawater and in soil to assess biodegradability. The results show that biodegradation by composting in soil was 81.25 % and 90.91 % for sample I (unfiltered pulp) and sample II (filtered pulp), respectively, and for seawater degradation by 0.46 cm2 and 1.15 cm2. These findings underscore the potential of tofu dregs protein-based bioplastics as an environmentally friendly and cost-effective alternative to conventional materials, thereby playing a significant role in the global effort to reduce plastic waste and inspiring further research and innovation in this field.