Enzyme-Assisted Preparation of Furcellaran-Like κ-/β-Carrageenan

Carrageenans are sulfated galactans that are widely used in industrial applications for their thickening and gelling properties, which vary according to the amount and distribution of ester sulfate groups along the galactan backbone. To determine and direct the sulfation of kappa-carrageenan moieties, we purified an endo-kappa-carrageenan sulfatase (Q15XH1 accession in UniprotKB) from Pseudoalteromonas atlantica T6c extracts. Based on sequence analyses and exploration of the genomic environment of Q15XH1, we discovered and characterized a second endo-kappa-carrageenan sulfatase (Q15XG7 accession in UniprotKB). Both enzymes convert kappa-carrageenan into a hybrid, furcellaran-like kappa-/beta-carrageenan. We compared the protein sequences of these two new kappa-carrageenan sulfatases and that of a previously reported tau-carrageenan sulfatase with other predicted sulfatases in the P. atlantica genome, revealing the existence of additional new carrageenan sulfatases.