Ethanol was produced by separate hydrolysis and fermentation usingAzolla filiculoidesas a biomass. Thermal acid hydrolysis and enzymatic saccharification were used as pretreatment methods to produce monosaccharides from Azolla. The optimal content for thermal acid hydrolysis of 14% (w/v) Azolla weed slurry produced 16.7-g/L monosaccharides by using 200 mM H(2)SO(4)at 121 degrees C for 60 min. Enzymatic saccharification using 16 U/mL Viscozyme produced 61.6 g/L monosaccharide at 48 h. Ethanol productions with ethanol yield coefficients from Azolla weed hydrolysate usingKluyveromyces marxianus,Candida lusitaniae Saccharomyces cerevisiae, andPichia stipitiswere 26.8 g/L (Y-EtOH = 0.43), 23.2 g/L (Y-EtOH = 0.37), 18.2 g/L (Y-EtOH = 0.29), and 13.7 g/L (Y-EtOH = 0.22), respectively.Saccharomyces cerevisiaeproduces the lowest yield as it utilized only glucose. Bioethanol from Azolla weed hydrolysate can be successfully produced by usingKluyveromyces marxianusbecause it consumed the mixture of glucose and xylose completely within 60 h.