Background: Algae manufacture a diversity of base materials that can be used for bioplastics assembly. The most essential compounds are carbohydrates and hydrocarbons. Polyhydroxybutyrate (PHB) is a polymer belonging to the polyester class that is of interest as bio-derived and biodegradable plastics. Results: In this study, three microalgal strains in addition to two microalgal biomass collected from high-rate algal ponds (HRAP) were used to detect their ability to produce polyhydroxybutrate for bioplastic production. The results showed that among the selected strains, Microcystis aeruginosa has the highest polyhydroxybutrate concentration (0.49 ± 0.5 mg mL −1 ). However, the biomass collected from the high-rate algal pond dominated with Microcystis sp. showed a higher concentration (0.7 ± 0.6 mg mL −1 ). Conclusion:The biomass collected from the high-rate algal pond dominated with Microcystis sp. was used for producing bioplastic since it has the highest concentration of PHB. Referring to plasticizing capacity, elongation at break (%) for algal biomass was 530% which was higher than that detected in blank which was 307%. So, it was obvious that the algal bioplastic has good plasticizing capacity.

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Background Algal biomass fermentation is one of the promising alternatives for bioethanol production. The bioethanol yield relies on fermentation conditions as the algal biomass amount, the yeast volume (% v/v), and the fermentation time. In this work, algal biomass harvested from a pilot-scale high rate algal pond (HRAP) was fermented anaerobically using immobilized Saccharomyces cerevisiae (ATCC 4126). The HRAP was constructed at the Zenin wastewater treatment plant (WTP), Giza, Egypt. A separate hydrolysis fermentation process (SHF) was applied for algal biomass. The effect of the algal biomass amount, the yeast volume (% v/v), and the time of fermentation as three independent variables were studied simultaneously and analyzed statistically using Design-Expert software V6.0.8. Results The harvested algal biomass from HRAP contains 45% carbohydrates and was dominated by Microcystis sp. The results revealed that optimum bioethanol yield 18.57 g/L is achieved by fermenting 98.7 g/L algae using 15.09% of the volume immobilized yeast for 43.6 h with a 95% confidence interval. Conclusion Microalgae grown on wastewater are a promising source of bioethanol production. Maximizing the ethanol production is achieved by optimizing the fermentation parameters as algal biomass, fermentation time, and yeast volume percent. The simultaneous optimization of the parameters using a statistical program is an effective way to maximize the production and predict a model that describes the relationship between these parameters and their response. The prospective research is going to study the effect of these predicted parameters on continuous fermentation on the semi-pilot scale.