Valorization of the cell wall polysaccharides of commercially cultivated Ulva ohnoi in Mexico

Abstract Ulva represents an important raw material due to its nutritional value. In addition, it contains cell wall polysaccharides, attractive for various applications. Ulva ohnoi is commercially cultivated in Baja California (México) and successfully marketed as human food. The valorization of this biomass as a source of ulvans and cellulose is proposed through a sequential extraction approach. As a first step, an ulvan with a 22.7% yield dry weight, high sulfate and uronic acids content, and with antioxidant capacity was obtained directly from the biomass. From the residual biomass, a semi-crystalline cellulose was recovered (3.8%) with potential for use in encapsulation and biocomposites. Fourier transform infrared (FTIR), and X-ray diffraction (XRD) analysis confirmed the structure of ulvans and cellulose and characterized the crystalline structure of the polysaccharides. Furthermore, using environmentally friendly technology through microwave-assisted extraction (MAE) and ionic liquid (IL), a cellulose derivative (CD) was isolated in the form of microcellulose, as observed by scanning electron microscopy. The results reinforced the potential of this species to diversify its use.