Optimation of the cell density, biomass production, lipid, and carbohydrate content of Nannochloropsis oculata with fluorescein and pH manipulation

Abstract

Nannochloropsis oculata is a potential marine microalga. However, the mass production of N. oculata encounters several challenges, such as the high costs of resources, contamination, and light absorption optimization. These problems can be solved by pH manipulation and fluorescein induction on culture media. Various studies have shown that pH values manipulation can cause fluctuations in cell density, dry biomass, and carbohydrate and lipid production of microalgae. On the other hand, fluorescein can act as a molecular antenna that improves light absorption. This research is novel because of its focus on its unique attempt to utilize pH manipulation combined with fluorescein induction to enhance the growth and metabolite production of N. oculata. The implications of this research may provide cost-effective, viable, and sustainable development of the algal industry in general. In this research, cultivation was carried out for seven days with four levels of pH (7 – 10) combined with three variations of fluorescein addition (0, 0.15, and 0.3 mL). Every treatment combination had three replications. Cell density and biomass as growth analysis parameters were calculated during the cultivation using the Haemocytometer and gravimetric methods. Bligh & Dyer and phenol sulfate methods were used to analyze lipid and carbohydrate content. Based on the result, the best treatment combination, pH 9 with 0.15 mL of fluorescein, increases cell density and carbohydrate content of N. oculata by 31.45 and 4.4%, albeit not statistically significant.