Lund University

About: Lund University is a education organization based out in Lund, Sweden. It is known for research contribution in the topics: Population & Cancer. The organization has 42345 authors who have published 124676 publications receiving 5016438 citations. The organization is also known as: Lunds Universitet & University of Lund.

Pretreatment of lignocellulosic materials for efficient bioethanol production.

Abstract: Second-generation bioethanol produced from various lignocellulosic materials, such as wood, agricultural or forest residues, has the potential to be a valuable substitute for, or a complement to, gasoline. One of the crucial steps in the ethanol production is the hydrolysis of the hemicellulose and cellulose to monomer sugars. The most promising method for hydrolysis of cellulose to glucose is by use of enzymes, i.e. cellulases. However, in order to make the raw material accessible to the enzymes some kind of pretreatment is necessary. During the last few years a large number of pretreatment methods have been developed, comprising methods working at low pH, i.e. acid based, medium pH (without addition of catalysts), and high pH, i.e. with a base as catalyst. Many methods have been shown to result in high sugar yields, above 90% of theoretical for agricultural residues, especially for corn stover. For more recalcitrant materials, e.g. softwood, acid hydrolysis and steam pretreatment with acid catalyst seem to be the methods that can be used to obtain high sugar and ethanol yields. However, for more accurate comparison of different pretreatment methods it is necessary to improve the assessment methods under real process conditions. The whole process must be considered when a performance evaluation is to be made, as the various pretreatment methods give different types of materials. (Hemicellulose sugars can be obtained either in the liquid as monomer or oligomer sugars, or in the solid material to various extents; lignin can be either in the liquid or remain in the solid part; the composition and amount/concentration of possible inhibitory compounds also vary.) This will affect how the enzymatic hydrolysis should be performed (e.g. with or without hemicellulases), how the lignin is recovered and also the use of the lignin co-product.

Constructing mystery: Empirical matters in theory development

Abstract: We outline a research methodology developed around two basic elements: the active discovery and/or creation of mysteries and the subsequent solving of the mysteries. A key element is the reflexive opening up of established theory and vocabulary through a systematic search for deviations from what would be expected, given established wisdom, in empirical contexts. “Data” are seen as an inspiration for critical dialogues between theoretical frameworks and empirical work.

A Method for the Fluorimetric Determination of Adrenaline and Noradrenaline in Tissues.1

Abstract: Summary. A method for chemical assay of small amounts of adrenaline and noradrenaline in tissues is described. The catechol amines are extracted with perchloric acid. The extracts are passed through a cation exchange column (Dowex 50) which takes up the catechol amines. Elution of the amines from the column is performed by hydrochloric acid. Estimation of the two amines in the eluates is made fluorimetrically after oxidation and rearrangement in alkali. Differentiation between adrenaline and noradrenaline is performed by utilizing the difference in the activation spectra of the fluoro-phores.

Increased tolerance and conversion of inhibitors in lignocellulosic hydrolysates by Saccharomyces cerevisiae

Abstract: During hydrolysis of lignocellulosic biomass, monomeric sugars and a broad range of inhibitory compounds are formed and released. These inhibitors, which can be organized around three main groups, furans, weak acids and phenolics, reduce ethanol yield and productivity by affecting the microorganism performance during the fermentation step. Among the microorganisms that have been evaluated for lignocellulosic hydrolysate ethanol fermentation, the yeast Saccharomyces cerevisiae appears to be the least sensitive. In order to overcome the effect of inhibitors, strategies that include improvement of natural tolerance of microorganism and use of fermentation control strategies have been developed. An overview of the origin, effects and mechanisms of action of known inhibitors on S. cerevisiae is given. Fermentation control strategies as well as metabolic, genetic and evolutionary engineering strategies to obtain S. cerevisiae strains with improved tolerance are discussed.