Studies On Ethanol Fermentation Of Extraction Liquor From Water Pre-hydrolysis Of Eucalyptus Prior To Pulping

Recently scholars in home and abroad advance that the separation of hemicellulose of raw material prior to chemical pulping,would facilitate a more effective hemicellulose utilization. The high-temperature extraction method.which is able to effectively extract the hemicellulose without destrorying the cellulose of raw material, causing no significant impact on the pulp is used to separate the hemicellulose. The major components of hemicellulose is pentose, including xylose, arabinose, etc., which can be used as carbon source of ethanol fermentation. High performance liquid chromatography(HPLC) was used to analyze the composition of the extraction liquor from water pre-hydrolysis of eucalyptus. The results confirmed that the components of the extraction liquor from water pre-hydrolysis of eucalyptus wood are complex and diverse, mainly containing xylose, xylan, galactose, lactose and arabinose, free of glucose and mannose, and extraction parameters (such as extraction temperature, time) have signficant effect on the composition and content of the extraction liquor from water pre-hydrolysis of eucalyptus.Ethanol fermentation of the extraction liquor from water pre-hydrolysis of eucalyptus were compared using the fusant SHY07-1 of the Pichia pastoris and the Saccharomyce cerevisiae,Pachysolen tannophilus and Candida lusitaneae. The results showed the fusant is more suitable for ethanol fermentation of the extraction liquor than the Pachysolen tannophilus and Candida lusitaniae, and the optimum fermentation conditions are temperature 33℃, pH 5.5 and liquid volume 80mL in 100mL bottle. The yield of 0.428g alcohol / g sugar can be reached using H160 as medium under above optimum conditions.The optimum hydrolysis conditions for mixture of cassava waste and extration liquor from water pre-hydrolysis of eucalyptus were sulfuric acid concentration of 4.0% and 30min. 95g/L of sugar content can be reached when mixture of 25mL H160 and 6.5g cassava waste was hydrolyzed under the conditions. 25g/L of ethanol accompanied with 9.83g/L glycerol and 13.43g/L butyric acid at 120h was detected when the hydrolysate was used for ethanol fermentation.