Bioplastic is one of the breakthroughs in the effort to reduce plastic waste. The bioplastic can be produced from microalgae with a high protein content, such as Spirulina platensis. The aim of this research was to produce S. platensis-based plastic with mechanical properties that mimics the commercial plastic bags. The microalgae were mixed with polyvinyl and maleic anhydride as compatibilizer to strengthen the bond between the microalgae and polymer. Glycerol was added as plasticizer to increase the flexibility. Observation was carried out on tensile strength and elongation of bioplastic with a variation of 15, 20, 25, and 30 wt% of glycerol content. The results show that the optimum plasticizer composition for this S. platensis-based bioplastic film was 30 wt%, which shows the tensile strength at 27.7 kgf/cm² and elongation at 66%. The tensile strength was very close to that of commercial plastic bags. The elongation property should be improved in order to be utilized for plastic bags. However, this bioplastic is very suitable for food, pharmacy, and cosmetic packaging materials that do not need high elongation.

Public demand for environmentally friendly packaging material especially in food industry is increasing. One of the many solutions invented for this problem is the development of biodegradable plastic. Biopolymer can be mixed with synthetic polymer to produce biodegradable films with properties suitable for varying applications. This study examines the mechanical physical properties of Chlorellapolyvinyl alcohol (PVA) based bioplastic by pre-treating the Chlorella powder with ultrasonic homogenizer. Variation of Chlorella concentration and temperature was done during the ultrasonication. Before being used as bioplastic base, pre-treated Chlorella with different concentrations were equated. Bioplastic films were then prepared with the pre-treated Chlorella powder and PVA using solvent casting method. Mechanical physical properties of the pre-treated Chlorella films then compared with non pretreated Chlorella film as control. Mechanical test shows the increasing of bioplastic tensile strength up to 15,3 kgf/cm² and elongation percentage up to 99,63%. Field emission scanning electron microscopy test shows the increasing of bioplastic homogenity and smoother surface with less pores. Fourier transform infrared analysis shows that there are crosslinkages between Chlorella and PVA. Thermal analysis by thermogravimetric analysis shows ultrasonication creates a more compact linkages. The performance of the film could suggest its potential as an eco-sustainable food packaging plastic material.