Amberlite XAD-4 resin was obtained from Sigma Aldrich (Mumbai, India). Amberlite XAD resins are nonionic macroreticular cross linked polymers of styrene divinyl benzene with a mean pore diameter of approximately 140 Å. Amberlite XAD-4 (1.5:1) was added to the hydrolysate and allowed to equilibrate at room temperature (28 ± 2 C) for 3 h. The resin-hydrolysate slurry was then filtered through Whatman #1 filter paper. The filtered hydrolysate was then adjusted to pH 6.5 with 0.1 N HCl and used for ABE fermentation [37].