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Biotechnology for Biofuels

Andreas H Förster, Sebastian Beblawy, Frederik Golitsch, Johannes Gescher
BACKGROUND: This paper describes the metabolic engineering of Escherichia coli for the anaerobic fermentation of glucose to acetoin. Acetoin has well-established applications in industrial food production and was suggested to be a platform chemical for a bio-based economy. However, the biotechnological production is often hampered by the simultaneous formation of several end products in the absence of an electron acceptor. Moreover, typical production strains are often potentially pathogenic...
2017: Biotechnology for Biofuels
Sierk de Jong, Kay Antonissen, Ric Hoefnagels, Laura Lonza, Michael Wang, André Faaij, Martin Junginger
BACKGROUND: The introduction of renewable jet fuel (RJF) is considered an important emission mitigation measure for the aviation industry. This study compares the well-to-wake (WtWa) greenhouse gas (GHG) emission performance of multiple RJF conversion pathways and explores the impact of different co-product allocation methods. The insights obtained in this study are of particular importance if RJF is included as an emission mitigation instrument in the global Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA)...
2017: Biotechnology for Biofuels
Mathieu Fanuel, Sona Garajova, David Ropartz, Nicholas McGregor, Harry Brumer, Hélène Rogniaux, Jean-Guy Berrin
BACKGROUND: The enzymatic conversion of plant biomass has been recently revolutionized by the discovery of lytic polysaccharide monooxygenases (LPMO) that catalyze oxidative cleavage of polysaccharides. These powerful enzymes are secreted by a large number of fungal saprotrophs and are important components of commercial enzyme cocktails used for industrial biomass conversion. Among the 33 AA9 LPMOs encoded by the genome of Podospora anserina, the PaLPMO9H enzyme catalyzes mixed C1/C4 oxidative cleavage of cellulose and cello-oligosaccharides...
2017: Biotechnology for Biofuels
Hidehiro Ishizawa, Masashi Kuroda, Masaaki Morikawa, Michihiko Ike
BACKGROUND: Duckweed (family Lemnaceae) has recently been recognized as an ideal biomass feedstock for biofuel production due to its rapid growth and high starch content, which inspired interest in improving their productivity. Since microbes that co-exist with plants are known to have significant effects on their growth according to the previous studies for terrestrial plants, this study has attempted to understand the plant-microbial interactions of a duckweed, Lemna minor, focusing on the growth promotion/inhibition effects so as to assess the possibility of accelerated duckweed production by modifying co-existing bacterial community...
2017: Biotechnology for Biofuels
Ian D Suckling, Michael W Jack, John A Lloyd, Karl D Murton, Roger H Newman, Trevor R Stuthridge, Kirk M Torr, Alankar A Vaidya
BACKGROUND: Conversion of softwoods into sustainable fuels and chemicals is important for parts of the world where softwoods are the dominant forest species. While they have high theoretical sugar yields, softwoods are amongst the most recalcitrant feedstocks for enzymatic processes, typically requiring both more severe pretreatment conditions and higher enzyme doses than needed for other lignocellulosic feedstocks. Although a number of processes have been proposed for converting softwoods into sugars suitable for fuel and chemical production, there is still a need for a high-yielding, industrially scalable and cost-effective conversion route...
2017: Biotechnology for Biofuels
Kaumeel Chokshi, Imran Pancha, Arup Ghosh, Sandhya Mishra
BACKGROUND: Microalgae accumulate a considerable amount of lipids and carbohydrate under nutrient-deficient conditions, which makes them one of the promising sustainable resources for biofuel production. In the present study, to obtain the biomass with higher lipid and carbohydrate contents, we implemented a short-term nitrogen starvation of 1, 2, and 3 days in a green microalga Acutodesmus dimorphus. Few recent reports suggest that oxidative stress-tolerant microalgae are highly efficient for biofuel production...
2017: Biotechnology for Biofuels
Tae Il Kim, Kwang Seok Ki, Dong Hyun Lim, Mayakrishnan Vijayakumar, Seong Min Park, Sun Ho Choi, Ki Young Kim, Seok Ki Im, Beom Young Park
BACKGROUND: N-acetyl-β-d-glucosamine (GlcNAc)6 is extensively used as an important bio-agent and a functional food additive. The traditional chemical process for GlcNAc production has some problems such as high production cost, low yield, and acidic pollution. Therefore, to discover a novel chitinase that is suitable for bioconversion of chitin to GlcNAc would be of great value. RESULTS: Here, we describe the complete isolation and functional characterization of a novel exo-chitinase from Acinetobacter parvus HANDI 309 for the conversion of chitin...
2017: Biotechnology for Biofuels
Tassia L Junqueira, Mateus F Chagas, Vera L R Gouveia, Mylene C A F Rezende, Marcos D B Watanabe, Charles D F Jesus, Otavio Cavalett, Artur Y Milanez, Antonio Bonomi
BACKGROUND: Ethanol production from lignocellulosic feedstocks (also known as 2nd generation or 2G ethanol process) presents a great potential for reducing both ethanol production costs and climate change impacts since agricultural residues and dedicated energy crops are used as feedstock. This study aimed at the quantification of the economic and environmental impacts considering the current and future scenarios of sugarcane biorefineries taking into account not only the improvements of the industrial process but also of biomass production systems...
2017: Biotechnology for Biofuels
Anja Poehlein, José David Montoya Solano, Stefanie K Flitsch, Preben Krabben, Klaus Winzer, Sharon J Reid, David T Jones, Edward Green, Nigel P Minton, Rolf Daniel, Peter Dürre
BACKGROUND: Microbial formation of acetone, isopropanol, and butanol is largely restricted to bacteria belonging to the genus Clostridium. This ability has been industrially exploited over the last 100 years. The solvents are important feedstocks for the chemical and biofuel industry. However, biological synthesis suffers from high substrate costs and competition from chemical synthesis supported by the low price of crude oil. To render the biotechnological production economically viable again, improvements in microbial and fermentation performance are necessary...
2017: Biotechnology for Biofuels
Guangsheng Pei, Tao Sun, Shuo Chen, Lei Chen, Weiwen Zhang
BACKGROUND: The unicellular model cyanobacterium Synechocystis sp. PCC 6803 is considered a promising microbial chassis for biofuel production. However, its low tolerance to biofuel toxicity limits its potential application. Although recent studies showed that bacterial small RNAs (sRNAs) play important roles in regulating cellular processes in response to various stresses, the role of sRNAs in resisting exogenous biofuels is yet to be determined. RESULTS: Based on genome-wide sRNA sequencing combined with systematic analysis of previous transcriptomic and proteomic data under the same biofuel or environmental perturbations, we report the identification of 133 trans-encoded sRNA transcripts with high-resolution mapping of sRNAs in Synechocystis, including 23 novel sRNAs identified for the first time...
2017: Biotechnology for Biofuels
Joachim Kopka, Stefanie Schmidt, Frederik Dethloff, Nadin Pade, Susanne Berendt, Marco Schottkowski, Nico Martin, Ulf Dühring, Ekaterina Kuchmina, Heike Enke, Dan Kramer, Annegret Wilde, Martin Hagemann, Alexandra Friedrich
BACKGROUND: Future sustainable energy production can be achieved using mass cultures of photoautotrophic microorganisms, which are engineered to synthesize valuable products directly from CO2 and sunlight. As cyanobacteria can be cultivated in large scale on non-arable land, these phototrophic bacteria have become attractive organisms for production of biofuels. Synechococcus sp. PCC 7002, one of the cyanobacterial model organisms, provides many attractive properties for biofuel production such as tolerance of seawater and high light intensities...
2017: Biotechnology for Biofuels
Constantinos Katsimpouras, Konstantinos G Kalogiannis, Aggeliki Kalogianni, Angelos A Lappas, Evangelos Topakas
BACKGROUND: Lignocellulosic biomass is an abundant and inexpensive resource for biofuel production. Alongside its biotechnological conversion, pretreatment is essential to enable efficient enzymatic hydrolysis by making cellulose susceptible to cellulases. Wet oxidation of biomass, such as acetone/water oxidation, that employs hot acetone, water, and oxygen, has been found to be an attractive pretreatment method for removing lignin while producing less degradation products. The remaining enriched cellulose fraction has the potential to be utilized under high gravity enzymatic saccharification and fermentation processes for the cost-competing production of bioethanol...
2017: Biotechnology for Biofuels
Hongting Tang, Meihui Song, Yao He, Jiajing Wang, Shenghuan Wang, Yu Shen, Jin Hou, Xiaoming Bao
BACKGROUND: Cellulase expression via extracellular secretion or surface display in Saccharomyces cerevisiae is one of the most frequently used strategies for a consolidated bioprocess (CBP) of cellulosic ethanol production. However, the inefficiency of the yeast secretory pathway often results in low production of heterologous proteins, which largely limits cellulase secretion or display. RESULTS: In this study, the components of the vesicle trafficking from the endoplasmic reticulum (ER) to the Golgi and from the Golgi to the plasma membrane, involved in vesicle budding, tethering and fusion, were over-expressed in Clostridium thermocellum endoglucanase (CelA)- and Sacchromycopsis fibuligera β-glucosidase (BGL1)-secreting or -displaying strains...
2017: Biotechnology for Biofuels
Johanna Olofsson, Zsolt Barta, Pål Börjesson, Ola Wallberg
BACKGROUND: Cellulase enzymes have been reported to contribute with a significant share of the total costs and greenhouse gas emissions of lignocellulosic ethanol production today. A potential future alternative to purchasing enzymes from an off-site manufacturer is to integrate enzyme and ethanol production, using microorganisms and part of the lignocellulosic material as feedstock for enzymes. This study modelled two such integrated process designs for ethanol from logging residues from spruce production, and compared it to an off-site case based on existing data regarding purchased enzymes...
2017: Biotechnology for Biofuels
Demi T Djajadi, Aleksander R Hansen, Anders Jensen, Lisbeth G Thygesen, Manuel Pinelo, Anne S Meyer, Henning Jørgensen
BACKGROUND: Understanding factors that govern lignocellulosic biomass recalcitrance is a prerequisite for designing efficient 2nd generation biorefining processes. However, the reasons and mechanisms responsible for quantitative differences in enzymatic digestibility of various biomass feedstocks in response to hydrothermal pretreatment at different severities are still not sufficiently understood. RESULTS: Potentially important lignocellulosic feedstocks for biorefining, corn stover (Zea mays subsp...
2017: Biotechnology for Biofuels
Amanda M Johnson, Hoon Kim, John Ralph, Shawn D Mansfield
BACKGROUND: Significant variation in the inherent degree of acetylation naturally exists in the xylem cell walls of Populus trichocarpa. During pretreatment, endogenous acetate hydrolyzes to acetic acid that can subsequently catalyze the breakdown of poplar wood, increasing the efficiency of biomass pretreatment. RESULTS: Poplar genotypes varying in cell wall composition were pretreated in 0.3% H2SO4 in non-isothermal batch reactors. Acetic acid released from the wood was positively related to sugar release during pretreatment (R ≥ 0...
2017: Biotechnology for Biofuels
Tooran Khazraie, Yiqian Zhang, Dmitry Tarasov, Weijue Gao, Jacquelyn Price, Nikolai DeMartini, Leena Hupa, Pedram Fatehi
BACKGROUND: Hot water hydrolysis process is commercially applied for treating wood chips prior to pulping or wood pellet production, while it produces hydrolysis liquor as a by-product. Since the hydrolysis liquor is dilute, the production of value-added materials from it would be challenging. RESULTS: In this study, acidification was proposed as a viable method to extract (1) furfural and acetic acid from hot water hydrolysis liquor and (2) lignin compounds from the liquor...
2017: Biotechnology for Biofuels
In Jung Kim, Nari Seo, Hyun Joo An, Jae-Han Kim, Paul V Harris, Kyoung Heon Kim
BACKGROUND: Lytic polysaccharide monooxygenase (LPMO) is a group of recently identified proteins that catalyze oxidative cleavage of the glycosidic linkages of cellulose and other polysaccharides. By utilizing the oxidative mode of action, LPMOs are able to enhance the efficiency of cellulase in the hydrolysis of cellulose. Particularly, auxiliary activity family 9 (AA9) is a group of fungal LPMOs that show a type-dependent regioselectivity on cellulose in which Types 1, 2, and 3 hydroxylate at C1, C4, and C1 and C4 positions, respectively...
2017: Biotechnology for Biofuels
Erin L Bredeweg, Kyle R Pomraning, Ziyu Dai, Jens Nielsen, Eduard J Kerkhoven, Scott E Baker
[This corrects the article DOI: 10.1186/s13068-016-0687-7.].
2017: Biotechnology for Biofuels
Daochen Zhu, Peipei Zhang, Changxiao Xie, Weimin Zhang, Jianzhong Sun, Wei-Jun Qian, Bin Yang
BACKGROUND: Lignin is the most abundant aromatic biopolymer in the biosphere and it comprises up to 30% of plant biomass. Although lignin is the most recalcitrant component of the plant cell wall, still there are microorganisms able to decompose it or degrade it. Fungi are recognized as the most widely used microbes for lignin degradation. However, bacteria have also been known to be able to utilize lignin as a carbon or energy source. Bacillus ligniniphilus L1 was selected in this study due to its capability to utilize alkaline lignin as a single carbon or energy source and its excellent ability to survive in extreme environments...
2017: Biotechnology for Biofuels
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