Jelian Grace L. Gontiñas, Luis K. Cabatingan, Yi-Hsu Ju, Alchris W. Go, Mary Alfil A. Curayag, Jenearly Z. Baloro
Wastes generated from carrageenan processing industry include cellulosic filter cakes (CFC) which are mainly composed of structural sugar (0.25 w/w) and ash (0.75 w/w, primarily perlite). This study investigated the possible valorization of CFC by recovering the available sugars as glucose through direct acid hydrolysis. Five different sulfuric acid concentrations (5% v/v to 15% v/v) were used as catalyst for hydrolysis done at constant temperature and solvent-to-solid ratio of 95°C and 8 mL/g, respectively, over a reaction time of 5 to 300 minutes, to determine the effect of acid concentration on the hydrolysis yield. The maximum sugar yield achieved was only ~0.06 w/w, corresponding to a recovery of ~24%, for hydrolysis done with 10% v/v sulfuric acid for 120 minutes. Although the amount of sugar recovered was relatively low, hydrolysates obtained have a sugar concentration of ~7 g/L, a level considered adequate for substrates in some fermentation processes. In addition, none of the inhibitory compound, 5-hydroxymethylfurfural, was present in the hydrolysate. Drying of residual solids obtained after hydrolysis was found to result in the sulfonation of the remaining organic fraction, producing a sulfonated residue (with total acid density of 4 to 7 mmol H+/g) which may be used as solid acid catalyst. © 2019 Cisa Publisher.
Department of Chemical Engineering, University of San Carlos, Talamban, Cebu City, 6000, Philippines; Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Keelung Road, Taipei City, Taiwan; National Taiwan University of Science and Technology, Keelung Road, Taipei City, Taiwan
