OPTIMASI KONSENTRASI N-NITRAT PADA KULTIVASI ARTHROSPIRA SP. UNTUK MENINGKATKAN KADAR PROTEIN DAN ASTAKSANTIN MENGGUNAKAN MEDIUM LIMBAH CAIR PERIKANAN LELE

• Main Author: Musaad, Syukriah
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/76169
• Institution: Institut Teknologi Bandung

Aquaculture produces liquid waste that can potentially be used as a medium for microalgae. Arthrospira sp. (spirulina) is a microalgae rich in protein and can produce astaxanthin. The nitrogen concentration in the medium is one factor that can affect protein and astaxanthin synthesis. Therefore, it is necessary to determine the appropriate N concentration in the medium to achieve high protein and astaxanthin content. In this study, Arthrospira sp. was cultivated using catfish fishery wastewater medium with the addition of NaNO3 to obtain variations in the total N-nitrate concentration: 23.3 mM, 46.6 mM, 93.3 mM, and a control (without NaNO3 addition). The measured parameters included specific growth rate, doubling time, biomass productivity, protein content, and astaxanthin content. The protein content was tested using alkaline cell disruption and Bradford methods, while astaxanthin was extracted through maceration and measured using HPLC. The cultivation was carried out in stages, starting with cultivation in 1 L culture bottles for 16 days, followed by pre-scaling up to the optimum N-nitrate concentration in a 10 L vertical tubular reactor (VTR), and scaling up in a 38 L open raceway pond (ORP). The results showed that the highest specific growth rate was achieved at a concentration of 23.3 mM N-nitrate, with a value of 0.215/day and a doubling time of 3.27 days. As the N-nitrate concentration in the medium increased, the uptake of N and P by microalgae also increased. The highest biomass productivity was obtained at a concentration of 46.6 mM N-nitrate, with a value of 0.04 g/L/day. The highest protein and astaxanthin content was achieved at 23.3 mM N-nitrate, with 32% (w/w) values and 12.19 ?g/g, respectively. The protein content of Arthrospira sp. cultivated in a medium with a concentration of 23.3 mM N-nitrate at the scaling-up stage in the ORP was 48.1% (w/w). Cultivating Arthrospira sp. using catfish fishery wastewater medium with a concentration of 23.3 mM N-nitrate resulted in higher growth rates and protein content than using the commercial Zarrouk medium in other studies.