Showing papers by "David J. Leak published in 2010"

Brown rot fungal early stage decay mechanism as a biological pretreatment for softwood biomass in biofuel production

Abstract: A current barrier to the large-scale production of lignocellulosic biofuels is the cost associated with the energy and chemical inputs required for feedstock pretreatment and hydrolysis. The use of controlled partial biological degradation to replace elements of the current pretreatment technologies would offer tangible energy and cost benefits to the whole biofuel process. It has been known for some time from studies of wood decay that, in the early stages of growth in wood, brown rot fungi utilise a mechanism that causes rapid and extensive depolymerisation of the carbohydrate polymers of the wood cell wall. The brown rot hyphae act as delivery vectors to the plant cell wall for what is thought to be a combination of a localised acid pretreatment and a hydroxyl radical based depolymerisation of the cell wall carbohydrate polymers. It is this quality that we have exploited in the present work to enhance the saccharification potential of softwood forest residues for biofuel production. Here we show that after restricted exposure of pine sapwood to brown rot fungi, glucose yields following enzymatic saccharification are significantly increased. Our results demonstrate the potential of using brown rot fungi as a biological pretreatment for biofuel production. © 2010 Elsevier Ltd.

Biobutanol:A better biofuel?

Abstract: Global energy demand and concerns over greenhouse gas emissions have increased interest in producing fuels which are compatible with current transportation infrastructure, from renewable sources. In recent years the profile of bio-butanol has been raised due to its perceived advantages over the traditionally considered gasoline substitute, bio-ethanol. In this review, traditional acetone-butanol-ethanol production by solventogenic clostridia is discussed. Different strategies have been employed to increase butanol productivity and overcome problems with toxicity; however a poor understanding of the regulatory networks governing butanol fermentation and lack of efficient genetic tools for clostridia has hampered progress in improving butanol titres. The butanol biosynthetic pathway from clostridia has been expressed in a range of alternative hosts; however reported butanol yields achieved are currently not comparable to those produced from clostridial fermentation. Nevertheless, microorganisms able to tolerate substantially higher concentrations of butanol than clostridia have been isolated, indicating that this may ultimately be the preferred route. Problems with toxicity can be alleviated by the use of an efficient butanol recovery system.

Methylotrophs, Industrial Applications

Abstract: Introduction Microbiology and Ecology Growth on C1 Compounds Metabolic Biochemistry and Energetics Biomass Production Growth Yields and Energetics Biomass Production from Methanol Potential Applications Processes Dependent on Substrate Economics Amino Acid Production Biodegradable Plastics from Methanol Processes Based on C1 Metabolism Methane Monooxygenase Methanol Dehydrogenase Methanol or Alcohol Oxidase Formate Dehydrogenase Applications Fortuitously Associated with C1 Metabolism Heterologous Gene Expression in Methylotrophic Yeasts Production of Vitamins and Coenzymes Concluding Remarks Bibliography Keywords: amino acids; bioremediation; biotransformation; methane; methanol; polyhydroxyalkanoates; polysaccharides; ribulose monophosphate pathway; serine pathway; single-cell protein; xylulose monophosphate pathway

Modified microorganisms geobacillus thermoglucosidasius with inactivated lactate dehydrogenase gene and use thereof in the production of ethanol

Abstract: The invention relates to modified microorganisms prepared by inactivation of the endogenous lactate dehydrogenase gene in strains geobacillus thermoglucocosidasius under NCIMB Accession Nos. 41277, 41278, 41279, 41280 and 41281. Said microorganisms can be used in the production of ethanol.