PRODUKSI PROTEIN DAN BIOMASSA DARI KULTIVASI MIXED CULTURE CHLORELLA VULGARIS DAN NANNOCHLOROPSIS SP. DALAM MEDIUM LIMBAH PERIKANAN

• Main Author: Mazidna Annisa, Isna
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/63066
• Institution: Institut Teknologi Bandung

Microalgae are known to be an alternative source of high-quality protein. However, the high cost of cultivation and the vulnerability of microalgae culture to environmental changes are major challenges in the commercial microalgae cultivation process. Both can be minimized by using a wastewater as a medium for microalgae growth and also by cultivating two species of microalgae in one container (mixed culture), which is known to improve culture stability. Therefore, this study aimed to determine the effect of mixed culture Chlorella vulgaris and Nannoschloropsis sp. on the growth rate of microalgae, protein production, chlorophyll production, and the concentration of inorganic compounds decrease in the fish culture waste medium. In this study, cultivation was carried out in a 20 L scale Vertical Tubular Reactor (VTR) in a fish culture liquid waste medium, with three variations of treatment. Among them are monoculture treatments of C. vulgaris, monoculture of Nannochloropsis sp., and mixed culture of C. vulgaris and Nannochloropsis sp. (1:1) for 7 days. The highest growth rate of microalgae (0.505 day-1) was obtained from the monoculture of C. vulgaris, followed by the growth rate of mixed culture (0.309 day-1) and monoculture of Nannochloropsis sp. (0.224 day-1). Although C. vulgaris predominated, the mixed culture treatment had an exponentially longer phase than the monoculture treatment so that it could produce higher biomass productivity (0.955 gL-1day-1). The mixed culture in this study also produced the highest protein content (45.58%) compared to the monoculture treatment (4.99% and 22.4%). Meanwhile, the highest maximum chlorophyll content was obtained from Nannochloropsis monoculture (17.52 mg/L), followed by mixed culture treatment (13.49 mg/L) and C. vulgaris monoculture (1.88 mg/L). This shows that the mixed culture can affect the chlorophyll content produced due to the dominance of one species. This study also showed that although the mixed culture treatment had the highest biomass productivity, the mixed culture treatment had a lower percentage value and rate of reduction of nitrate, ammonium, and phosphate compounds (4.22-43.11%) compared to the monoculture treatment. (9.85-87.56%). This shows that mixed culture microalgae cells tend to use the nutrients obtained for cell division, so the mixed culture treatment requires fewer nutrients to produce more biomass. It can be concluded that in this study the mixed culture treatment showed better performance in protein production and microalgae biomass, but less good in chlorophyll production and decreased inorganic compounds in fish culture liquid waste medium.