ABSTRACT
ABSTRACT The aim of this study was to evaluate the antioxidant activity of ethyl acetate and methanolic extracts of two marine algae, Nannochloropsis oculata and Gracilaria gracilis. The extracts were assayed for total phenol and flavonoid content, DPPH free radical scavenging capacity, nitric oxide activity, iron chelation activity, and reducing power activity. Total phenol and flavonoid content were found to be high in both algae. Ethyl acetate extracts of both algae were found to exhibit significant antioxidant activity. Ethyl acetate extract of N. oculata exhibited a good capacity for iron chelation, nitrate oxide, and scavenging DPPH free radicals (72.95±2.30, 73.73±1.76, and 39.03±0.97% inhibition at 400 µg mL-1 respectively).
Subject(s)
Seaweed/classification , In Vitro Techniques , Antioxidants/analysis , Flavonoids/analysis , Phenol/analysisABSTRACT
This study aimed at evaluating the best conditions for lipid accumulation in the marine microalga Nannochloropsis oculata in an airlift photobioreactor. Experiments were carried out following a central composite design with the following variables: temperature (19 to 29°C), sodium nitrate concentration (NaNO3) in the culture medium (f/2) (25 to 125 mg.L-1) and incident light intensity (49 to 140 µE.m-2s-1). The maximum lipid production was 132.4 mg.L-1 under the following conditions: 27°C, NaNO3 concentration 105 mg.L-1 and 122 µE.m-2.s-1, which was 30% of dry weight of the biomass.
ABSTRACT
Industrial culture media for cultivation of marine microalgae Nannochloropsis oculata was optimized by using Random Design software. High eicosapentaenoic acid (EPA) content was obtained over 40% of total fatty acid, and high average specific growth rate of 0.32d -1 was obtained in cells grown in the selected Formula 1. Mass cultivation of this species was practiced in indoor open raceway ponds of 6.12 m 2 and 28.02 m 2, and in outdoor open pond of 83.50 m 2 during May and June in 1999. The average area yield of biomass were obtained at 2.77, 1.62 and 2.52 g /m 2?d, and in October, 1.09 g/ m 2?d was obtained in 83.5m 2 outdoor pond, and the harvest algae powder contained 49.50% of protein, 20.30% of total lipid and 3.00% of EPA of dry weight. With high temperature tolerant species during August in 2000, the average area yield of biomass were increased to 5.44?9.96 and 7.66 g/ m 2?d in above ponds, respectively and 2.50% of EPA of dry weight was contained in the powder. It is indicated that the industrialized cultivation of Nannochloropsis oculata rich in EPA is completely doable on practice, and the algal powder was a good raw material as single cell protein and development of EPA rich products.