Escherichia coli for biofuel production: bridging the gap from promise to practice

Huffer, Sarah; Roche, Christine M.; Blanch, Harvey W.; Clark, Douglas S.

doi:10.1016/j.tibtech.2012.07.002

Cited by 91 publications

(72 citation statements)

References 61 publications

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“…However, the requirement for removing solids as a prerequisite to aerobic bioconversion is not yet fully understood. The relatively limited literature on hydrocarbon metabolic pathways focuses almost exclusively on using glucose or standard commodity hexose-based sugars (e.g., sugarcane juice, corn syrup) [33]; thus, performance with lignocellulosic hydrolysate, also including pentose sugars and solubilized lignin-derived compounds, is not yet quantified. From a cost standpoint it may be preferential to allow solids to pass through the bioconversion step to be removed downstream (as in the case of the ethanol process), as this may allow for the use of a lower-cost separation system and ultimately increase yield by avoiding sugar losses that are incurred in the upstream 26 separation; however, a tradeoff could be incurred by increasing the complexity of downstream product recovery in such a scenario.…”

Section: Design Basismentioning

confidence: 99%

Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Biological Conversion of Sugars to Hydrocarbons

Davis¹,

Tao²,

Tan³

et al. 2013

307

569

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The U.S. Department of Energy (DOE) promotes the production of a range of liquid fuels and fuel blendstocks from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in this program, the National Renewable Energy Laboratory (NREL) investigates the conceptual production economics of these fuels.Between 1999 and 2012, NREL conducted a campaign to quantify the economic implications associated with measured conversion performance for the biochemical production of cellulosic ethanol, with a formal program between 2007-2012 to set cost goals and to benchmark annual performance toward achieving these goals, namely the pilot-scale demonstration by 2012 of biochemical ethanol production at a price competitive with petroleum gasoline based on modeled assumptions for an "n th " plant biorefinery. This goal was successfully achieved through NREL's 2012 pilot plant demonstration runs, representing the culmination of NREL research focused specifically on cellulosic ethanol, and a benchmark for industry to leverage as it commercializes the technology. This important milestone also represented a transition toward a new Program focus on infrastructure-compatible hydrocarbon biofuel pathways, and the establishment of new research directions and cost goals across a number of potential conversion technologies.This report describes in detail one potential conversion process to hydrocarbon products by way of biological conversion of lignocellulosic-derived sugars. The pathway model leverages expertise established over time in core conversion and process integration research at NREL, while adding in new technology areas primarily for hydrocarbon production and associated processing logistics. The overarching process design converts biomass to a hydrocarbon intermediate, represented here as a free fatty acid, using dilute-acid pretreatment, enzymatic saccharification, and bioconversion. Ancillary areas-feed handling, hydrolysate conditioning, product recovery and upgrading (hydrotreating) to a final blendstock material, wastewater treatment, lignin combustion, and utilities-are also included in the design. Detailed material and energy balances and capital and operating costs for this baseline process are also documented.This benchmark case study techno-economic model provides a production cost for a cellulosic renewable diesel blendstock (RDB) that can be used as a baseline to assess its competitiveness and market potential. It can also be used to quantify the economic impact of individual conversion performance targets and prioritize these in terms of their potential to reduce cost. The analysis presented here also includes consideration of the life-cycle implications of the baseline process model, by tracking sustainability metrics for the modeled biorefinery, including greenhouse gas (GHG) emissions, fossil energy demand, and consumptive water use.Building on prior design reports for bioch...

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Section: Design Basismentioning

confidence: 99%

Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Biological Conversion of Sugars to Hydrocarbons

Davis¹,

Tao²,

Tan³

et al. 2013

307

569

View full text Add to dashboard Cite

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“…During the bioconversion process, the lignin and the hemicellulosic parts are first degraded into simpler sugars and/or organic acids, followed by a deoxygenating step to produce a liquid fuel [4]. Design of a genetically modified microorganism for direct lignocellulosic biomass conversion purposes has recently been taken into consideration [5]. The production of several types of fuel through direct lignocellulosic biomass conversions has been demonstrated by various studies [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…E. coli has been considered a convenient biocatalyst in biofuel production for its fermentation of glucose into a wide range of short-chain alcohols [9,10], and production of highly deoxygenated hydrocarbon through fatty acid metabolism [11,12]. Moreover, the ability to ferment several pentoses and hexoses makes E. coli an ideal ethanologen for biofuel production [5,13].…”

Section: Introductionmentioning

confidence: 99%

Molecular Cloning and Expression of Cellulase and Polygalacturonase Genes in E. coli as a Promising Application for Biofuel Production

Ibrahim¹,

Jones²,

Hossenya³

2013

J Pet Environ Biotechnol

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Lignocellulosic biomass has potential for bioethanol, a renewable fuel. A limitation is that bioconversion of the complex lignocellulosic material to simple sugars and then to bioethanol is a challenging process. Recent work has focused on the genetic engineering of a biocatalyst that may play a critical role in biofuel production. Escherichia coli have been considered a convenient host for biocatalysts in biofuel production for its fermentation of glucose into a wide range of short-chain alcohols and production of highly deoxygenated hydrocarbon. The bacterium Pectobacterium carotovorum subsp. carotovorum (P. carotovorum) is notorious for its maceration of the plant cell wall causing soft rot. The ability to destroy plants is due to the expression and secretion of a wide range of hydrolytic enzymes that include cellulases and polygalacturonases. P. carotovorum ATCC™ no. 15359 was used as a source of DNA for the amplification of celB, celC and peh. These genes encode 2 cellulases and a polygalacturonase, respectively. Primers were designed based on published gene sequences and used to amplify the open reading frames from the genomic DNA of P. carotovorum. The individual PCR products were cloned into the pTAC-MAT-2 expression vector and transformed into Escherichia coli. The deduced amino acid sequences of the cloned genes have been analyzed for their catalytically active domains. Estimation of the molecular weights of the expressed proteins was performed using SDS-PAGE analysis and celB, celC and peh products were approximately 29.5 kDa, 40 kDa 41.5 kDa, respectively. Qualitative determination of the cellulase and polygalacturonase activities of the cloned genes was carried out using agar diffusion assays.

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“…Although ethanol has been the focus of much research in the past few decades, its shortcomings as a fuel have led to metabolic engineering of microbial hosts to produce fuels with more desirable properties such as butanol, isobutanol medium to long-chain hydrocarbons and isoprenoids [15,16]. Bioethanol has been used in automobiles with gasoline in different blending proportions [17,18]. However, biobutanol is considered an advanced biofuel, because of its good properties of high heat value, high hydrophobicity, reduced corrosive activity, high viscosity and low volatility.…”

Section: Review Of the Literature And Discussionmentioning

confidence: 99%

Theoretical and Practical Studies on the Metabolic Engineering of Streptomyces for Production of Butanols

Doori

Hunter

2017

JMEN

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Production of biofuels is a significant technical and commercial challenge. To compete effectively with fossil fuels, the efficiency of processes that convert sustainable feedstocks to biofuel has to be improved. Ideally, the ultimate aim is a single process that degrades the renewable feedstock quickly and delivers high titers of biofuel at a price that is competitive with equivalent fuel from fossil sources. However, the microbes that are currently being investigated for biofuel production fall into two categories: those that degrade cellulosic feedstock but cannot make biofuels effectively and those that do make biofuels but are poor at degrading the cellulosic feedstock. When biofuel production is engineered into cellulose degraders, or cellulose degradation engineered into microbes with capability to produce biofuel, another factor, lignin content (a toxic component in most sustainable feedstocks), comes into play. This review considers the latent opportunity to harness Streptomyces bacteria to address this issue.Keywords: Feedstocks; Production; Butanol; Decarbonisation; Streptomyces Theoretical and Practical Studies on the Metabolic Engineering of Streptomyces for Production of Butanols 2/4Copyright: ©2017 Doori et al.Microbes make a significant contribution to the production of biofuels [6][7]. However, the yield of product by native microbes is uneconomic, which makes it necessary to develop and improve them through strategies of systems and synthetic biology [8][9]. Alcohol producers, such as Saccharomyces cervisiae which are excellent at fermenting sugars to alcohols, cannot digest lignocelluloses. A combination of pretreatment [10,11] of the feedstock and genetic engineering of the yeast, results in utilization of the cellulose and hemi-cellulose, but hydrolysis products of lignin are toxic to yeast. Other natural alcohol producers, e,g. the bacterium Zymomonas mobilis, have similar problems of lignin toxicity.Therefore, the choice of organism(s) should be based on those that have a proven ability to degrade lignocelluloses, be impervious to toxicity of lignin and be comparatively fast growing. They should also be amenable to genetic manipulation and ideally have been used industrially for large scale fermentation. This mini-review considers the latent potential of Streptomyces bacteria to make a significant contribution to biofuel production, using biobutanol as an example. Although notable for antibiotic production, these resilient bacteria seem to have been overlooked in the context of biofuel production. Review of the Literature and DiscussionThe soil Actinomycetes are notable as being adopted by industry, particularly for large-scale production of antibiotics. Most actinomycetes do not normally produce significant quantities of alcohols. However, introduction of the key enzymes into strains can stimulate alcohol (ethanol) production. The critical enzymes are pyruvate decarboxylase and alcohol dehydrogenase. Corynebacterium glutamicum [12,13] and several Streptomyces sp. [14] have bee...

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Escherichia coli for biofuel production: bridging the gap from promise to practice

Cited by 91 publications

References 61 publications

Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Biological Conversion of Sugars to Hydrocarbons

Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Biological Conversion of Sugars to Hydrocarbons

Molecular Cloning and Expression of Cellulase and Polygalacturonase Genes in E. coli as a Promising Application for Biofuel Production

Theoretical and Practical Studies on the Metabolic Engineering of Streptomyces for Production of Butanols

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