2.4. Analytical methods
The moisture was measured as the weight loss of 1 g RS or its
hydrolyzed residues dried at 105C for 24 h[24]. The cellulose
content in RS or its hydrolyzed residues was determined by means
of HNO3-ethanol method [24]. The lignin content in RS or its
hydrolyzed residues was assayed by the 72% (w/w) H2SO4method
[24]. The hemicellulose content in RS or its hydrolyzed residues
was analyzed according to two-brominating method[24]. The glucose content in the fermentation broth was measured by means of
glucose oxidase method[25]. The xylose content in the fermentation broth was analyzed by the means of the phloroglucinol
method[26]. The fermentable sugars concentration in the fermentation broth was estimated using the 3,5-dinitrosalicylic acid
method[27]. The ethanol content in the fermentation broth was
determined by gas chromatography[28