scispace - formally typeset
Search or ask a question
Author

David J. Leak

Bio: David J. Leak is an academic researcher from University of Bath. The author has contributed to research in topics: Fermentation & Methane monooxygenase. The author has an hindex of 31, co-authored 118 publications receiving 8681 citations. Previous affiliations of David J. Leak include University of Warwick & National Technical University.


Papers
More filters
Journal ArticleDOI
27 Jan 2006-Science
TL;DR: The integration of agroenergy crops and biorefinery manufacturing technologies offers the potential for the development of sustainable biopower and biomaterials that will lead to a new manufacturing paradigm.
Abstract: Biomass represents an abundant carbon-neutral renewable resource for the production of bioenergy and biomaterials, and its enhanced use would address several societal needs. Advances in genetics, biotechnology, process chemistry, and engineering are leading to a new manufacturing concept for converting renewable biomass to valuable fuels and products, generally referred to as the biorefinery. The integration of agroenergy crops and biorefinery manufacturing technologies offers the potential for the development of sustainable biopower and biomaterials that will lead to a new manufacturing paradigm.

5,344 citations

Journal ArticleDOI
TL;DR: In this paper, ground lignocellulosic biomass (Miscanthus giganteus, pine (Pinus sylvestris) and willow (Salix viminalis) was pretreated with ionic liquid-water mixtures of 1-butyl-3methylimidazolium methyl sulfate and 1- butyl- 3methyloridehydrogensulfate hydrogen sulfate.

427 citations

Journal ArticleDOI
TL;DR: Results indicated that the copper effect could explain a similar switch in intracellular location observed in Methylosinus trichosporium OB3b but that some methanotrophs do not have the capacity to overcome copper stress in this way.
Abstract: The intracellular location of methane mono-oxygenase (MMO) activity in the methanotroph Methylococcus capsulatus (Bath) has been shown to depend primarily on the availability of copper. MMO activity was observed in the particulate fraction of cell extracts under conditions of copper excess but switched to a soluble location in response to copper stress. The two activities could be differentiated by sensitivity to a range of inhibitors and by major changes in the polypeptide banding patterns on denaturing polyacrylamide gels. MMO activity concomitant with the oxidation of ethanol was only observed in cells with particulate MMO activity but could be lost independently in response to copper stress. Examination of other methanotrophs indicated that the copper effect could explain a similar switch in intracellular location observed in Methylosinus trichosporium OB3b but that some methanotrophs do not have the capacity to overcome copper stress in this way.

380 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the anion of ionic liquids on air-dried pine (Pinus radiata) has been investigated and it was shown that 1-butyl-3methylimidazolium dicyanamide dissolves neither cellulose nor lignocellulosic material.

316 citations

Journal ArticleDOI
TL;DR: The metabolic engineering of two strains of Geobacillus thermoglucosidasius to divert their fermentative carbon flux from a mixed acid pathway, to one in which ethanol becomes the major product, which involved elimination of the lactate dehydrogenase and pyruvate formate lyase pathways.

253 citations


Cited by
More filters
28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481 4.2.1.
Abstract: 3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481

5,127 citations

Journal ArticleDOI
TL;DR: A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts.
Abstract: Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for "consolidated bioprocessing" (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts.

4,769 citations

Journal ArticleDOI
TL;DR: It is found that the composition of most microbial groups is sensitive and not immediately resilient to disturbance, regardless of taxonomic breadth of the group or the type of disturbance, and a simple framework to incorporate microbial community composition into ecosystem process models is proposed.
Abstract: Although it is generally accepted that plant community composition is key for predicting rates of ecosystem processes in the face of global change, microbial community composition is often ignored in ecosystem modeling. To address this issue, we review recent experiments and assess whether microbial community composition is resistant, resilient, or functionally redundant in response to four different disturbances. We find that the composition of most microbial groups is sensitive and not immediately resilient to disturbance, regardless of taxonomic breadth of the group or the type of disturbance. Other studies demonstrate that changes in composition are often associated with changes in ecosystem process rates. Thus, changes in microbial communities due to disturbance may directly affect ecosystem processes. Based on these relationships, we propose a simple framework to incorporate microbial community composition into ecosystem process models. We conclude that this effort would benefit from more empirical data on the links among microbial phylogeny, physiological traits, and disturbance responses. These relationships will determine how readily microbial community composition can be used to predict the responses of ecosystem processes to global change.

2,117 citations