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Abstract Although they are the largest taxonomic group of animals, relatively few insects have been examined for symbiotic relationships with micro-organisms. However, this is rapidly changing because of the potential for examination of the natural insect–microbe–lignocellulose interactions to provide insights for biofuel technology. Micro-organisms associated with lignocellulose-consuming insects often facilitate the digestion of the recalcitrant plant diet; therefore these microbial communities may be mined for novel lignocellulose-degrading microbes, or for robust and inexpensive biocatalysts necessary for economically feasible biofuel production from lignocellulose. These insect–microbe interactions are influenced by the ecosystem and specific lignocellulose diet, and appreciating the whole ecosystem–insect–microbiota–lignocellulose as a natural biorefinery provides a rich and diverse framework from which to design novel industrial processes. One such natural biorefinery, the Tipula abdominalis larvae in riparian ecosystems, is reviewed herein with applications for biochemical processes and overcoming challenges involved in conversion of lignocellulosic biomass to fuel ethanol. From the dense and diverse T. abdominalis larval hindgut microbial community, a cellulolytic bacterial isolate, 27C64, demonstrated enzymatic activity toward many model plant polymers and also produced a bacterial antibiotic. 27C64 was co-cultured with yeast in fermentation of pine to ethanol, which allowed for a 20% reduction of commercial enzyme. In this study, a micro-organism from a lignocellulose-consuming insect was successfully applied for improvement of biomass-to-biofuel technology. 相似文献
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The search for petroleum alternatives has motivated intense research into biological breakdown of lignocellulose to produce
liquid fuels such as ethanol. Degradation of lignocellulose for biofuel production is a difficult process which is limited
by, among other factors, the recalcitrance of lignocellulose and biological toxicity of the products. Consolidated bioprocessing
has been suggested as an efficient and economical method of producing low value products from lignocellulose; however, it
is not clear whether this would be accomplished more efficiently with a single organism or community of organisms. This review
highlights examples of mixtures of microbes in the context of conceptual models for developing symbiotic consortia for biofuel
production from lignocellulose. Engineering a symbiosis within consortia is a putative means of improving both process efficiency
and stability relative to monoculture. Because microbes often interact and exist attached to surfaces, quorum sensing and
biofilm formation are also discussed in terms of consortia development and stability. An engineered, symbiotic culture of
multiple organisms may be a means of assembling a novel combination of metabolic capabilities that can efficiently produce
biofuel from lignocellulose. 相似文献
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Liu ZL 《Applied microbiology and biotechnology》2011,90(3):809-825
Pretreatment of lignocellulose biomass for biofuel production generates inhibitory compounds that interfere with microbial
growth and subsequent fermentation. Remediation of the inhibitors by current physical, chemical, and biological abatement
means is economically impractical, and overcoming the inhibitory effects of lignocellulose hydrolysate poses a significant
technical challenge for lower-cost cellulosic ethanol production. Development of tolerant ethanologenic yeast strains has
demonstrated the potential of in situ detoxification for numerous aldehyde inhibitors derived from lignocellulose biomass
pretreatment and conversion. In the last decade, significant progress has been made in understanding mechanisms of yeast tolerance
for tolerant strain development. Enriched genetic backgrounds, enhanced expression, interplays, and global integration of
many key genes enable yeast tolerance. Reprogrammed pathways support yeast functions to withstand the inhibitor stress, detoxify
the toxic compounds, maintain energy and redox balance, and complete active metabolism for ethanol fermentation. Complex gene
interactions and regulatory networks as well as co-regulation are well recognized as involved in yeast adaptation and tolerance.
This review presents our current knowledge on mechanisms of the inhibitor detoxification based on molecular studies and genomic-based
approaches. Our improved understanding of yeast tolerance and in situ detoxification provide insight into phenotype-genotype
relationships, dissection of tolerance mechanisms, and strategies for more tolerant strain development for biofuels applications. 相似文献
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木质纤维素的微生物降解 总被引:1,自引:0,他引:1
木质纤维素广泛存在于自然界中,因结构复杂,其高效降解需要多种微生物的协同互作,由于参与木质纤维素降解的微生物种类繁多,其协同降解机理尚不完全明确。随着微生物分子生物学和组学技术的快速发展,将为微生物协同降解木质纤维素机制的研究提供新的方法和思路。笔者前期研究发现,细菌复合菌系在50℃下表现出强大的木质纤维素降解能力,菌系由可分离培养和暂时不可分离培养细菌组成,但是可分离培养细菌没有降解能力。通过宏基因组和宏转录组研究表明,与木质纤维素降解相关的某些基因表达量发生显著变化,通过组学方法有可能更加深入解释微生物协同降解木质纤维素的微生物学和酶学机理。文中从酶、纯培养菌株和复合菌群三个方面综述了木质纤维素微生物降解研究进展,着重介绍了组学技术在解析复合菌群作用机理方面的现状和应用前景,以期为探索微生物群落协同降解木质纤维素的机理提供借鉴。 相似文献
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Adav SS Ravindran A Chao LT Tan L Singh S Sze SK 《Journal of proteome research》2011,10(10):4579-4596
Bioenergy, particularly biofuel, from lignocellulosic biomass has been considered as one of the most promising renewable and sustainable energies. The industrial productivity and efficiency of microbial lignocellulolytic enzymes for cellulosic biofuel applications are significantly affected by pH of culture condition. This study established and compared hydrolytic protein expression profiles of Trichoderma reesei QM6a, QM9414, RUT C30 and QM9414MG5 strains at different pH in cellulosic culture media. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of secretome of T. reesei cultured from pH 3.0-9.0 revealed significantly higher hydrolytic protein expressions at acidic pH. The Bray-Curtis similarity indices, clustering, and Shannon diversity index elucidated differences in protein secretion at different pHs in individuals and among the strains. This study demonstrated a comparative lignocellulolytic enzyme secretion profile of T. reesei and its mutants at different pHs and provides pH sensitive and resistance enzyme targets for industrial lignocellulose hydrolysis. 相似文献
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João R. M. Almeida Magnus Bertilsson Marie F. Gorwa-Grauslund Steven Gorsich Gunnar Lidén 《Applied microbiology and biotechnology》2009,82(4):625-638
There is a growing awareness that lignocellulose will be a major raw material for production of both fuel and chemicals in
the coming decades—most likely through various fermentation routes. Considerable attention has been given to the problem of
finding efficient means of separating the major constituents in lignocellulose (i.e., lignin, hemicellulose, and cellulose)
and to efficiently hydrolyze the carbohydrate parts into sugars. In these processes, by-products will inevitably form to some
extent, and these will have to be dealt with in the ensuing microbial processes. One group of compounds in this category is
the furaldehydes. 2-Furaldehyde (furfural) and substituted 2-furaldehydes—most importantly 5-hydroxymethyl-2-furaldehyde—are
the dominant inhibitory compounds found in lignocellulosic hydrolyzates. The furaldehydes are known to have biological effects
and act as inhibitors in fermentation processes. The effects of these compounds will therefore have to be considered in the
design of biotechnological processes using lignocellulose. In this short review, we take a look at known metabolic effects,
as well as strategies to overcome problems in biotechnological applications caused by furaldehydes. 相似文献
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Biofuel cells and their development 总被引:15,自引:0,他引:15
This review considers the literature published since 1994 on microbial and enzymatic biofuel cells. Types of biofuel cell are classified according to the nature of the electrode reaction and the nature of the biochemical reactions. The performance of fuel cells is critically reviewed and a variety of possible applications is considered. The current direction of development of biofuel cells is carefully analysed. While considerable chemical development of enzyme electrodes has occurred, relatively little progress has been made towards the engineering development biofuel cells. The limit of performance of biofuel cells is highlighted and suggestions for future research directions are provided. 相似文献
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Biofuel alternatives to ethanol: pumping the microbial well 总被引:2,自引:0,他引:2
Fortman JL Chhabra S Mukhopadhyay A Chou H Lee TS Steen E Keasling JD 《Trends in biotechnology》2008,26(7):375-381
Engineered microorganisms are currently used for the production of food products, pharmaceuticals, ethanol fuel and more. Even so, the enormous potential of this technology has yet to be fully exploited. The need for sustainable sources of transportation fuels has generated a tremendous interest in technologies that enable biofuel production. Decades of work have produced a considerable knowledge-base for the physiology and pathway engineering of microbes, making microbial engineering an ideal strategy for producing biofuel. Although ethanol currently dominates the biofuel market, some of its inherent physical properties make it a less than ideal product. To highlight additional options, we review advances in microbial engineering for the production of other potential fuel molecules, using a variety of biosynthetic pathways. 相似文献
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Although the potential for biofuel production from microalgae via photosynthesis has been intensively investigated, information on the selection of a suitable operation strategy for microalgae-based biofuel production is lacking. Many published reports describe competitive strains and optimal culture conditions for use in biofuel production; however, the major impediment to further improvements is the absence of effective engineering strategies for microalgae cultivation and biofuel production. This comprehensive review discusses recent advances in understanding the effects of major environmental stresses and the characteristics of various engineering operation strategies on the production of biofuels (mainly biodiesel and bioethanol) using microalgae. The performances of microalgae-based biofuel-producing systems under various environmental stresses (i.e., irradiance, temperature, pH, nitrogen depletion, and salinity) and cultivation strategies (i.e., fed-batch, semi-continuous, continuous, two-stage, and salinity-gradient) are compared. The reasons for variations in performance and the underlying theories of the various production strategies are also critically discussed. The aim of this review is to provide useful information to facilitate development of innovative and feasible operation technologies for effectively increasing the commercial viability of microalgae-based biofuel production. 相似文献
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The increasing oil price and environmental concerns caused by the use of fossil fuel have renewed our interest in utilizing biomass as a sustainable resource for the production of biofuel. It is however essential to develop high performance microbes that are capable of producing biofuels with very high efficiency in order to compete with the fossil fuel. Recently, the strategies for developing microbial strains by systems metabolic engineering, which can be considered as metabolic engineering integrated with systems biology and synthetic biology, have been developed. Systems metabolic engineering allows successful development of microbes that are capable of producing several different biofuels including bioethanol, biobutanol, alkane, and biodiesel, and even hydrogen. In this review, the approaches employed to develop efficient biofuel producers by metabolic engineering and systems metabolic engineering approaches are reviewed with relevant example cases. It is expected that systems metabolic engineering will be employed as an essential strategy for the development of microbial strains for industrial applications. 相似文献
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Antonio D. Moreno David Ibarra Pablo Alvira Elia Tomás-Pejó Mercedes Ballesteros 《Critical reviews in biotechnology》2015,35(3):342-354
Future biorefineries will integrate biomass conversion processes to produce fuels, power, heat and value-added chemicals. Due to its low price and wide distribution, lignocellulosic biomass is expected to play an important role toward this goal. Regarding renewable biofuel production, bioethanol from lignocellulosic feedstocks is considered the most feasible option for fossil fuels replacement since these raw materials do not compete with food or feed crops. In the overall process, lignin, the natural barrier of the lignocellulosic biomass, represents an important limiting factor in biomass digestibility. In order to reduce the recalcitrant structure of lignocellulose, biological pretreatments have been promoted as sustainable and environmentally friendly alternatives to traditional physico-chemical technologies, which are expensive and pollute the environment. These approaches include the use of diverse white-rot fungi and/or ligninolytic enzymes, which disrupt lignin polymers and facilitate the bioconversion of the sugar fraction into ethanol. As there is still no suitable biological pretreatment technology ready to scale up in an industrial context, white-rot fungi and/or ligninolytic enzymes have also been proposed to overcome, in a separated or in situ biodetoxification step, the effect of the inhibitors produced by non-biological pretreatments. The present work reviews the latest studies regarding the application of different microorganisms or enzymes as useful and environmentally friendly delignification and detoxification technologies for lignocellulosic biofuel production. This review also points out the main challenges and possible ways to make these technologies a reality for the bioethanol industry. 相似文献
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Potential of biofilm-based biofuel production 总被引:1,自引:0,他引:1
Biofilm technology has been extensively applied to wastewater treatment, but its potential application in biofuel production
has not been explored. Current technologies of converting lignocellulose materials to biofuel are hampered by costly processing
steps in pretreatment, saccharification, and product recovery. Biofilms may have a potential to improve efficiency of these
processes. Advantages of biofilms include concentration of cell-associated hydrolytic enzymes at the biofilm–substrate interface
to increase reaction rates, a layered microbial structure in which multiple species may sequentially convert complex substrates
and coferment hexose and pentose as hydrolysates diffuse outward, and the possibility of fungal–bacterial symbioses that allow
simultaneous delignification and saccharification. More importantly, the confined microenvironment within a biofilm selectively
rewards cells with better phenotypes conferred from intercellular gene or signal exchange, a process which is absent in suspended
cultures. The immobilized property of biofilm, especially when affixed to a membrane, simplifies the separation of biofuel
from its producer and promotes retention of biomass for continued reaction in the fermenter. Highly consolidated bioprocessing,
including delignification, saccharification, fermentation, and separation in a single reactor, may be possible through the
application of biofilm technology. To date, solid-state fermentation is the only biofuel process to which the advantages of
biofilms have been applied, even though it has received limited attention and improvements. The transfer of biofilm technology
from environmental engineering has the potential to spur great innovations in the optimization of biofuel production. 相似文献
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Corn-based fuel ethanol production processes provide several advantages which could be synergistically applied to overcome
limitations of biofuel processes based on lignocellulose. These include resources such as equipment, manpower, nutrients,
water, and heat. The fact that several demonstration-scale biomass ethanol processes are using corn as a platform supports
this viewpoint. This report summarizes the advantages of first-generation corn-based biofuel processes and then describes
the technologies, advantages, and limitations of second-generation lignocellulose-based biofuel systems. This is followed
by a discussion of the potential benefit of fully integrating first- and second-generation processes. We conclude with an
overview of the technology improvements that are needed to enhance the profitability of biofuel production through development
of an integrated biorefinery. A key requirement is creation of industrially robust, multifunctional ethanologens that are
engineered for maximum ethanol production from mixed sugars. In addition to ethanol, combined biorefineries could also be
the source of valuable co-products, such as chemicals and plastics. However, this will require expression systems that produce
high-value co-products. Advantages of this approach are that (1) such strains could be used for bioconversion in any part
of the combined biorefinery and (2) using one recombinant organism with many additions should simplify the process of obtaining
necessary FDA approval for feed products produced by or containing recombinant organisms. 相似文献
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Shihui Yang Yaoping Zhang Lydia M. Contreras Sagar M. Utturkar Steven D. Brown Michael E. Himmel Min Zhang 《Microbial biotechnology》2016,9(6):699-717
Zymomonas mobilis is a natural ethanologen with many desirable industrial biocatalyst characteristics. In this review, we will discuss work to develop Z. mobilis as a model system for biofuel production from the perspectives of substrate utilization, development for industrial robustness, potential product spectrum, strain evaluation and fermentation strategies. This review also encompasses perspectives related to classical genetic tools and emerging technologies in this context. 相似文献
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Marla Tuffin Dominique Anderson Cal Heath Don A. Cowan Professor 《Biotechnology journal》2009,4(12):1671-1683
Metagenomics emerged in the late 1990s as a tool for accessing and studying the collective microbial genetic material in the environment. The advent of the technology generated great excitement, as it has provided new opportunities and technologies for studying the wealth of microbial genetic diversity in the environment. Metagenomics has been widely predicted to access new dimensions of protein sequence space. A decade on, we review how far we have actually moved into new sequence space (and other aspects of protein space) using metagenomic tools. While several novel enzyme activities and protein structures have been identified through metagenomic strategies, the greatest advancement has been made in the isolation of novel protein sequences, some of which have no close relatives, form deeply branched lineages and even represent novel families. This is particularly true for glycosyl hydrolases and lipase/esterases, despite the fact that these activities are frequently screened for in metagenomic studies. However, there is much room for improvement in the methods employed and they will need to be addressed so that access to novel biocatalytic activities can be widened. 相似文献