Investigating the effects of process parameters on microalgae growth, lipid extraction, and stable nanoemulsion productions

Abstract

Microalgae, Spirulina platensis, of the class Cyanobacteria, was produced in a 10-gallon tank using starter mix under simulated sunlight. Dried microalgae were frozen at –40 C for three days to stress the microalgae to increase the lipid content. The research investigated the algal oil obtained (about 36 wt%) with the FT-IR and NMR technique to assess the functional groups, triglycerides, and fatty acids, and to assess whether the oil was suitable for further intended usage. The ultra-sonication technique was implemented for the algal oil in water mixed with sodium dodecyl sulfate i (SDS) (surfactant) to make stable nanoemulsions. Nanoemulsions, which were assessed through the UV–vis spectroscopy technique, generated promising results regarding the changes in particle sizes and concentrations. Nanoemulsions of different SDS concentrations and constant sonication time of 10 min gave better results. The particle size analysis conducted through dynamic light scattering (DLS) was a critical approach used in the research to perceive the meta-stable nature of the nanoemulsions (stable over 5–10 weeks without phase separation or color change). The particle size of the algal oil was reduced to 17.92 nm when emulsified with 0.2 wt% SDS in water and it remained stable. This study suggests promising new techniques for developing nanoemulsions from algal oil for applications in food-related products, fuel blends, and cosmetics, as it has good absorbance rate and stability.