Influence of Light Intensity and Photoperiod on the Photoautotrophic Growth and Lipid Content of the Microalgae Verrucodesmus verrucosus in a Photobioreactor

Abstract

Microalgal biomass has the capacity to accumulate relatively large quantities of triacylglycerides (TAG) for the conversion of methyl esters of fatty acids (FAME) which has made microalgae a desirable alternative for the production of biofuels. In the present work Verrucodesmus verrucosus was evaluated under autotrophic growth conditions as a suitable source of oil for biodiesel production. For this purpose BG11 media were evaluated in three different light:dark photoperiods (L:D; 16:08; 12:12; 24:0) and light intensities (1000, 2000 and 3000 Lux) in a photobioreactor with a capacity of three liters; the evaluation of the microalgal biomass was carried out through the cell count with the use of the Neubauer chamber followed by the evaluation of the kinetic growth parameters. So, the lipid accumulation was determined through the lipid extraction with a Soxhlet system. Finally, the fatty acid profile of the total pooled lipids was determined using gas chromatography-mass spectroscopy (GC-MS). The results demonstrate that the best conditions are a photoperiod of 12 light hours and 12 dark hours with BG11 medium in a 3 L tubular photobioreactor with 0.3% CO2, 25 °C and 2000 Lux, allowing a lipid accumulation of 50.42%. Palmitic acid is identified as the most abundant fatty acid at 44.90%.

The Role of Photo-Cycles in the Modulation of Growth and Biochemical Profile of Microalgae: Part I—Food Interest Compounds

“…By modifying the duration of the light/dark cycles, it is possible to change the biochemical composition of microalgae. For example, the conversions of phosphoenolpyruvate to pyruvate and 3-phosphoglycerate to glycerol 3-phosphate are candidate limiting steps for lipid accumulation during light/dark cycling [ 57 ]. The accumulation of substrates, including ribulose 5-phosphate, during dark periods, can be explained by the close relationship of increased biomass yield with improved CO 2 fixation, related to the metabolic profile, to carbohydrate synthesis and mainly to the lipid pathway (phosphoenolpyruvate; PEP, pyruvate, and acetyl-CoA), as detailed in Figure 3 .…”

Enhanced Scenedesmus obliquus Cultivation in Plastic-Type Flat Panel Photobioreactor for Biodiesel Production

“…The appropriate light intensity levels for microalgae growth vary from one species to another and also vary according to the byproduct that will be produced from the algae [42,43]. Vélez-Landa et al [44] studied three levels of light intensity, i.e., 1000, 2000, and 3000 lux, in cultivating the microalga Verrucodesmus verrucosus (in a three-liter photobioreactor) as a biodiesel feedstock. Based on the microalgal biomass (through the cell count), lipid content, and fatty acid profile of the extracted lipids, the light intensity of 2000 lux was reported as the illumination condition.…”

The Discovery and Characterization of a Novel Microalgal Strain, Picochlorum sp. KCTC AG61293, with Potential for α-Linolenic Acid Production

“…For example, variations in nutrient availability can significantly affect the production of specific fatty acids [71,72]. Similarly, light conditions, including intensity and photoperiod, can affect microalgal growth and the levels of lipids, carotenoids, and fatty acid composition [73][74][75]. Therefore, the optimization of these conditions is critical for maximizing fatty acid production.…”