EFFECTS OF DIFFERENT LIGHT WAVELENGTH ON BIOMASS PRODUCTION AND LIPIDS ACCUMULATION OF THE MARINE NANNOCHLOROPSIS SP. STRAIN 72

Microalgae are considered promising candidates for production of high-value human, spanning from pharmaceutical and cosmetic applications to biofuel production, and animal foodstuffs and additives. Many factors influence both microalgal biomass and lipids production, among these, light is of primary importance. In this work, we evaluated the effects of light (wavelength emitted) by Light-Emitting Diodes (LEDs), as monochromatic blue (λ=450nm), red (λ=660nm), white (λ=400-700 nm), and mixed lighting (blue and red), at intensity of 100 μmol photons m−2 s−1, on the biomass production and lipids accumulation of the marine microalgal strain 72, in photoautotrophic conditions, continuously bubbled with atmospheric air in BG11 medium, at 25°C and pH 7, for ten days. After phenotypic and genotypic characterization, strain 72, isolated from a water sample collected from the Strait of Messina (Italy), was strictly related to Nannochloropsis sp. (98.6% similarity to Nannochloropsis salina CCMP1776). When exposed to white LEDs, the biomass production by Nannochloropsis sp. strain 72 (1.28 g/l) was higher than that produced by Nannochloropsis oculata (0.39 g/l), and lipids yield from strain 72 was also higher than that from N. oculata (0.16 and 0.058 g/l). When exposed to red light, Nannochloropsis sp. strain 72 produced a very high amount of biomass (2.5 g/l) that could be a potential eco-sustainable and non-toxic alternative as agricultural soil improver or fish-feed in aquaculture. Lipids produced after exposition to white light, will be further characterized and, accordingly to their properties, they will be addressed for different uses in pharmaceutical and cosmetic applications and biodiesel production.