Biopolymer detection in Egyptian microalgae: A pathway to eco-friendly bioplastics

With the increase in pollution resulting from plastic waste, it was a necessity to reduce the danger of its waste to the environment. Hence, replacing traditional plastic with bioplastic is a must. Bioplastic is more environmentally friendly materials, such as plastic made from biological sources. Green and bluegreen microalgae have recently emerged as two of the most valuable sources. This study examines the viability of using microalgal cells to produce biopolymers, such as polyhydroxybutyrate, proteins, and carbohydrates. The study employed spectrophotometric standards to quantify the concentrations of polyhydroxybutyrate (PHB) and carbohydrates. Additionally, the Kjeldahl method was utilised to determine the total protein content. Five green microalgal strains and five blue green microalgal strains were examined. Chlorophyll a was measured to track growth. Growth rate assessments revealed that Selenastrum gracile exhibited the highest chlorophyll a concentration (6.9 μg/L) at 15 days, accompanied by the highest protein content at 41.13 %. Additionally, it displayed a PHB concentration of 325 mg/mL, while exhibiting the lowest carbohydrate levels (12 mg/ml). Polyhydroxybutrate content maximum concentration was detected in Microcystis aeruginosa 720.5 μg/mL, and 31 % concentration in proteins and carbohydrates (12.3 mg/ml). Selenastrum sp. is easily cultivated and offers potential for further research. Its application in bioplastic production, through blending with other polymers, is a promising avenue for future exploration.