Efficient production of fermentable sugars from oil palm empty fruit bunch by combined use of acid and whole cell culture-catalyzed hydrolyses.

Empty fruit bunch (EFB) of oil palm trees was converted to fermentable sugars by the combined use of dilute acids and whole fungal cell culture-catalyzed hydrolyses. EFB (5%, w/v) was hydrolyzed in the presence of 0.5% H2SO4 and 0.2% H3PO4 at 160 °C for 10 Min. The solid fraction was separated from the acid hydrolysate by filtration and subjected to enzymatic hydrolysis at 50 °C using the whole cell culture of Trichoderma reesei RUT-C30 (2%, w/v), which was prepared by cultivation at 30 °C for 7 days to reach its maximal cellulase activity. The combined hydrolyses of EFB gave a total sugar yield of 82.0%. When used as carbon sources for cultivating Escherichia coli in M9 medium at 37 °C, the combined EFB hydrolysates were shown to be more favorable or at least as good as pure glucose for cell growth in terms of the higher (1.1 times) optical density of E. coli cells. The by-products generated during the acid-catalyzed hydrolysis did not seem to obviously affect cell growth. The combined use of acid and whole cell culture hydrolyses might be a commercially promising method for pretreatment of lignocellulose to get fermentable sugars. [ABSTRACT FROM AUTHOR]