In this study, a biodegradable alternative to synthetic plastics was explored, where gelatinized corn starch was blended with polyvinyl alcohol (PVA) using the solution casting method at different ratios. Tensile tests showed that films made of only starch exhibited the lowest tensile strength at 3.66 MPa, which increased as the ratio of PVA in the blend was raised. The water vapor transmission rate was similar even when the starch content was changed. PVA was shown to increase the solubility of the film in water, and starch demonstrated a better ability to absorb water than that of PVA, with the pure starch film swelled up to 167 of its original weight. Fourier transform infrared (FTIR) analysis revealed that there was no significant chemical interaction between the starch and PVA which could alter their respective functional groups. Bioplastic films made of only starch showed the least amount of degradation after 3 days when buried in soil, while water uptake in films made of PVA caused it to turn into a sticky gel-like substance. Chlorella vulgaris exhibited a higher preference for PVA as the substrate when compared to starch. This revealed that C. vulgaris showed promise as a candidate for breaking down the bioplastic films when grown as a heterotroph. © 2021 Curtin University and John Wiley & Sons, Ltd.