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Microalgae play an important economic role as aquaculture feed. This study aimed to create an automated algae cultivation system with variable light intensity for the culture of Chlorella ellipsoidea strain TISTR 8260. The automated cabinet could work continuously for at least 30 days, with the growth rates of microalgae in culture systems with light intensities of 1000 Lux, 3000 Lux, and 5000 Lux peaking on day 14, whereas the fluorescent control showed peak microalgae growth on day 6. On day 30, the biomass harvested from microalgae grown in 1000 Lux, 3000 Lux, 5000 Lux, and fluorescent control was 0.1935 ± 0.151 mg/L, 0.1996 ± 0.220 mg/L, 0.2041 ± 0.159 mg/L, and 0.0674 ± 0.191 mg/L, respectively, which was not significantly different between the groups but significantly higher than the control (P-value = 0.05, DF = 3, F(3,36) = 7). The automated algae cabinet with a light intensity of 5000 Lux and a rotation speed of 150 r.p.m produced the maximum biomass, which was three times that produced by a fluorescent light source. [ABSTRACT FROM AUTHOR]

Shrimp production facilities produce large quantities of wastewater, which consists of organic and inorganic pollutants. High concentrations of these pollutants in shrimp wastewater cause serious environmental problems and, therefore, a method of treating this wastewater is an important research topic. This study investigated the impact of algae and indigenous bacteria on treating shrimp wastewater. A total of four different microalgae cultures, including Chlorococcum minutus, Porphyridum cruentum, Chlorella vulgaris and Chlorella reinhardtii along with two cyanobacterial cultures, Microcystis aeruginosa and Fishcherella muscicola were used with indigenous bacterial cultures to treat shrimp wastewater. The highest soluble chemical oxygen demand (sCOD) removal rate (95%) was observed in the samples that were incubated using F. muscicola. Total dissolved nitrogen was degraded >90% in the C. vulgaris, M. aeruginosa, and C. reinhardtii seeded samples. Dissolved organic nitrogen removal was significantly higher for C. vulgaris (93%) as compared to other treatments. Similarly, phosphate degradation was very successful for all the algae-bacteria consortium (>99%). Moreover, the degradation kinetics were calculated, and the lowest half-life (t 1/2) for sCOD (5 days) was recorded for the samples seeded with M. aeruginosa. Similarly, treatment with F. muscicola and C. reinhardtii showed the lowest t 1/2 of NH 3 –N (2.9 days) and phosphate (2.7 days) values. Overall, the results from this study suggest that the symbiotic relationship between indigenous bacteria and algae significantly enhanced the process of shrimp wastewater treatment within 21 days of incubation. The outcome of this study supports resource recovery in the aquaculture sector and could be beneficial to treat a large-scale shrimp facility's wastewater worldwide. [Display omitted] • Shrimp wastewater contains high levels of nitrogen and phosphate. • Algae-bacteria consortium is a feasible solution for a sustainable environment. • TDN and DON decreased (>90%) in the presence of algae-bacteria consortium. • Symbiotic relationship between algae and bacteria increased treatment performance. • Nutrients in wastewater are converted to biomass during the treatment. [ABSTRACT FROM AUTHOR]