Change in SPCS fiber properties during separate and simultaneous hydrolysis with cellulases and xylanase after 24 h. (A) Fiber length distribution. (B) Average fiber width. (C) Fiber surface area (combination interior/exterior) determined by Simons' staining technique. Enzyme loading (mg/g cellulose): cellulases (5), xylanase (30) and BSA (30). Control: substrates were incubated at the same condition without the addition of enzymes. BSA: bovine serum albumin; SPCS: steam pretreated corn stover.