Development of a sequential alkalic salt and dilute acid pretreatment for enhanced sugar recovery from corn cobs

This study presents a sequential sodium phosphate dodecahydrate (Na3PO4 center dot 12H(2)O) and sulfuric acid (H2SO4) pretreatment to enhance sugar release from corn cobs. The effects of Na3PO4 center dot 12H(2)O concentration, H2SO4 concentration and solid to liquid ratio on the reducing sugar yield were investigated. The developed model had a coefficient of determination value (R-2) of 0.98. Maximum reducing sugar yield of 0.99 +/- 0.01 g/g was obtained with 12.70% Na3PO4 center dot 12H(2)O, 1.04% H2SO4 and 14.49% solid to liquid ratio. A 9-fold increase in the sugar yield was observed compared to previous reports on corn cobs. An intelligent model was developed to determine functional relationships between the input and output parameters. Reducing sugar yield was majorly dependent on Na3PO4 center dot 12H(2)O concentration and fits a Weibull type of relationship. Sequential pretreatment of lignocellulosic material with alkalic salt and dilute acid significantly enhanced sugar recovery and demonstrated high efficiency for microbial production of biofuels and bioproducts.