Spectroscopic investigation of exopolysaccharides purified from Arthrospira platensis cultures as potential bioresources

Abstract

In this work, we employed Raman and Fourier-transform infrared (FTIR) spectroscopies in order to monitor in real time the exopolysaccharides (EPS) components purified from Arthrospira platensis AICB 49 (previously known as Spirulina sp.) species. Preliminary Raman and IR spectra for EPS obtained following a stepwise ethanol extraction are reported as compared to the dextran molecule, a well-known byproduct of wine fermentation. The Raman spectra were recorded with 2 commonly used excitation wavelengths, 532 nm and 633 nm, respectively. The final aim we pursue is empowering microbiological byproducts, that otherwise generate high disposal costs, which hold great promise as competitive and affordable industrial-grade staple. Once we succeed to tackle the accurate composition of such byproducts and their spectral fingerprint, we will be able to estimate their potential as bioresources. As a complementary technique, FTIR spectroscopy was additionally employed for a better elucidation of the molecular composition of the samples. We comprehensively assigned the recorded Raman and IR bands observed for the EPS extracted from A. platensis by assessing a molecular structure investigation and by corroborating the recorded spectral results with recent studies reporting similar saccharide-species.