Sequential multi-stage extraction of biocompounds from Spirulina platensis: Combined effect of ohmic heating and enzymatic treatment

Abstract

A sequential multi-stage procedure was applied on the extraction of biocompounds from Spirulina platensis. The process consisted in three steps: 1) aqueous extraction, using conventional thermal extraction (CE), ohmic heating (OH, 7V/cm), enzymatic treatment (EAE, 0.8 mgLysozyme/mL), or both OH and EAE combined; 2) ethanolic extraction; 3) CHCl3/MeOH extraction. The results evidenced that the combined OH-EAE extraction allowed selective recovery of phycobiliproteins in the 1st step, with increments of more than 100% in yield in comparison with CE. Pigments and lipids were selectively extracted in the 2nd step. The combination of OH and EAE in the 1st step resulted in higher amounts of extracted compounds in the following phases compared to processes using non-combined technologies. Results demonstrate that the intensification of extraction steps facilitates the use of environmentally friendly technologies in a multi-stage process capable of recovering and isolating different fractions with bio-functional properties, targeting waste reduction and circular economy. Industrial relevance Spirulina plantensis represents a potential biomass feedstock due to its potential as a source of compounds of great economic value (including antioxidants, proteins, lipids and natural pigments, in particular blue colorants). The combined use of ohmic heating and enzymes in the aqueous extraction step fosters the use of environmentally friendly technologies to implement sequential high yield and high purity extraction of the different valuable fractions with bio-functional properties, targeting waste reduction and contributing to the implementation of circular economy strategies. This can be integrated with a design of Industry 4.0 driving the development of new products.