Bioprospecting of cyanobacterium in Chilean coastal desert, Geitlerinema sp. molecular identification and pressurized liquid extraction of bioactive compounds

Abstract

This study presents a new cyanobacterium of the genus Geitlerinema sp. isolated from the Chilean coastal desert as a rich source of bioactive compounds. Phylogenetic tree is shown along with a broad biochemical characterization using conventional and pressurized liquid extraction. Variables as extraction yield, phycobiliproteins, lipids and methyl palmitate (C16:0) were studied by means of two experimental designs based on a response surface methodology (RSM) employing two factorial design 32. Factors as temperature (20–200 °C) and percentage of solvents were selected resulting in Factorial Design A with 0–100% (v/v) of ethanol–water and Factorial Design B with 0–100 (v/v) of ethanol–limonene solvents. The main bioactive compounds were total proteins (∼52% wt), phycobiliproteins (especially C-phycocyanin) and methyl palmitate (C16:0). Data obtained showed that water and ethanol:water (1:1, v/v) improved the extraction yield and phycobiliproteins recovery. As for ethanol:limonene extracts, they were better for lipids and methyl palmitate extractions. In general, high temperatures only improved the extraction yield whereas low temperatures favor the extraction of phycobiliproteins. Therefore, results indicated that Geitlerinema sp. could be one of the several cyanobacteria genera that display functional properties for nutritional, pharmaceutical or industrial use as sustainable and cost-effective bioactive compounds in algal biorefinery model.