Ionic liquid pre-treatment in tandem with recombinant agarase cocktail saccharification of Gelidium amansii for D-Galactose and 3,6-Anhydro-L-Galactose production

D-Galactose (D-Gal) and 3,6-Anhydro-L-Galactose (3,6-L-AHG) are valuable sugars that can be derived from Gelidium amansii. Herein, ionic liquid (IL) pre-treatment was used to deconstruct the cell wall of G. amansii without producing any side-products from sugar degradation. It is combined with enzymatic saccharification using recombinant agarases to effectively produce D-Gal and 3,6-L-AHG from IL-treated G. amansii. ILs were screened for the biomass pre-treatment as well as the anti-solvents for dissolved biomass retrieval from the IL. [Bmim]Ac is the most effective solvent (99% dissolution) and methanol as anti-solvent (78% reconstituted G. amansii). Using simplex-centroid design, the optimal loading of three β-agarases: Aga2, AgaA7 and Aga50D for the first hydrolysis was determined to be at equal fractions (0.33). Addition of α-neoagarobiose hydrolase AhgI finally produced maximum yields of 56.5% for D-Gal and 33.7% for 3,6-L-AHG. Given the industrial importance of D-Gal and the high market price of 3,6...