Study on Ethanol Fermentation Using D-Glucose Rich Fractions Obtained from Lignocelluloses by a Two-step Extraction with Sulfuric Acid and Issatchenkia Orientalis MF 121

Cellulosic oligosaccharides (720-920 mg) were prepared by a two-step extraction using 43.5% sulfuric acid and then 55% sulfuric acid from lignocelluloses (2 g each) of Japanese oak and eucalyptus as hardwood, Japanese cedar and cypress as softwood, and sugar cane bagasse and rice straw as annual plant residues. After the complete saccharification of the oligosaccharide and treatment with the appropriate amount of activated carbon, D-glucose with a comparatively high purity was prepared. As the D-glucose was in a strong sulfuric acid solution, the sugar solution was applied on a column packed with an ion exchanging resin (Diaion DSR01) in order to remove almost all of the acid. The fractions eluting the sugar were collected and concentrated with a rotary evaporator. Although the concentrated sugar solution showed an acidity of pH 2-3, acid tolerant Issatchenkia orientalis MF 121 could ferment ethanol successfully in YPD medium using the sugar as the sole source of carbon.