Processing and characterization of antimicrobial bioplastic films based on green microalgae Scenedesmus obliquus extract-loaded polyurethane

The green microalga Scenedesmus obliquus, isolated from the Egyptian environment, was used for the synthesis of bio-based plastic materials. Polyurethane (PU) was blended with different proportions (0%, 10%, 20%, and 40%) of chloroform extract to form bioplastic films. The bioplastic films were characterized using water vapor transmission rate measurements and scanning electron microscopy (SEM). The WVTR of pure PU was 193.37 g/ m2. day, while the values of algae/PU films were 129.74, 122.56, and 99.75 g/m2.day. S. obliquus reported having Palmitic, which possesses antimicrobial activity and acts as an effective antimicrobial agent in the syn-thesized bioplastic films. Antimicrobial activity of the algal extract and the synthesized bioplastic films were tested against two Gram-positive bacteria; Staphylococcus aureus, Enterococcus faecalis, two Gram-negative bac-teria; Escherichia coli, Pseudomonas aeruginosa, and Candida albicans as a model for fungi. The results indicated that S. obliquus extract exhibited a clear antimicrobial activity against all tested microbes. The antimicrobial rate of bioplastic films containing 40% of the extract reached 100% after 2 h of contact with E. coli and E. faecalis. In conclusion, this study offers a promising future for the use of biodegradable antimicrobial bioplastic films as an affordable and environmentally friendly alternative to plastics in many applications.