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Corn stalks, which are an abundant agricultural waste product in Turkey, have a high carbohydrate structural content and could be a valuable raw material for bioethanol production. In this study, stalks with crystalline cellulose and complex lignin and hemicellulose distribution in their structure were first steam-exploded and then chemically treated to achieve efficient hydrolysis. The conventional chemicals sodium hydroxide (NaOH), sulfuric acid (H2SO4), hydrogen peroxide (H2O2), and an alternative chemical, sodium borohydrate (NaBH4), were utilized in the chemical treatment procedure. Results showed that the samples treated with NaOH (83.9%) and NaBH4(82.9%) gave higher glucan conversion in enzymatic hydrolysis compared to those treated with H2O2(74.5%) and H2SO4(56.6%). The highest ethanol yield from untreated stalks (97.4 g/kg) was obtained when the stalks were pretreated with 4% NaBH4for 90 min; the theoretical ethanol yield was found to be 72.5%. [ABSTRACT FROM PUBLISHER]

As a new approach, the acidity that wood exhibits under moderate conditions is assayed by stimulated dissociation of weak wood acids in lightly basic secondary phosphate solutions. To assure a sufficient dissociation of hardly soluble weak acids in the solution, the amount of wood suspended in Na2HPO4 solutions should be small but vary depending on the degree of acidity of wood species. However, the difficulties are associated with the titration of very dilute acids limiting the precision of the measurement. If the disintegrated wood is suspended in a secondary phosphate solution, the weak woods acids form the conjugate acid Na2HPO4 from secondary phosphate Na2HPO4 resulting in a pH fall of the solution. The decrease in the pH value in phosphate solution, which depends on the wood acidity, can be evaluated to estimate the acidity arising from wood under moderate conditions. [ABSTRACT FROM AUTHOR]

In order to differentiate two varieties of Cupressus sempervirens, volatile foliage isolates obtained from 12 trees of variety horizontalis and 12 trees of var. pyramidalis were analyzed by GC and GC/MS. About 86-87% of total peak areas of chromatograms consist of monoterpenes and evaluating their composition in qualitative and quantitative manner they do not show significant differences with regard to varieties. Some increments of terpinen-4-ol, α-terpineol and α-terpinyl acetate was recognizable in the variety horizontalis, while the variety pyramidalis contained germacrene D and abietadiene to somewhat higher level. On the other side, a higher percentage of α-fenchene than that of camphene and the presence of a monoterpene hydrocarbon sylvestrene were found to bear some chemotaxonomic value for the taxon C. sempervirens. [ABSTRACT FROM AUTHOR]