Abstract:
BACKGROUND:Photosynthetic production of chemicals and fuels by recycling CO2 in cyanobacteria is a promising solution facing energy shortage and resource declination. Ethanol is an attractive and demonstrative biofuel product, and ethanol synthesis in cyanobacteria has been achieved by assembling of a pathway consisting of pyruvate decarboxylase (PDCzm) and alcohol dehydrogenase II (slr1192). For enabling more powerful ethanol photosynthetic production, an optimized and balanced catalyzing route was required. In this work, we provided a paradigm for systematically characterizing and optimizing the PDCzm-slr1192 pathway from engineered cyanobacteria strains, combining in vitro reconstitution, genetic engineering and feeding-cultivation. RESULTS:We reconstituted the PDCzm-slr1192 pathway in vitro and performed specific titration assays for enzymes, substrates, cofactors, and metal ions. In the in vitro system, K 50 of PDCzm was 0.326 μM, with a V max of 2.074 μM/s; while for slr1192, the values were 0.109 μM and 1.722 μM/s, respectively. Titration response discrepancy indicated that PDCzm rather than slr1192 was the rate-limiting factor for ethanol synthesis. In addition, a 4:6 concentration ratio of PDCzm-slr1192 would endow the reaction with a maximal specific catalytic activity. Titration assays for other components were also performed. K m values for NADPH, pyruvate, TPP, Mg(2+) and acetaldehyde were 0.136, 6.496, 0.011, 0.104, and 0.393 mM, respectively. We further constructed Synechocystis mutant strains with diverse PDCzm-slr1192 concentrations and ratios, and compared the growth and ethanol synthesis performances. The results revealed that activities of PDCzm indeed held control over the ethanol generation capacities. We performed pyruvate-feeding treatment with the newly developed Syn-YQ4 strain, and confirmed that improvement of pyruvate supply would direct more carbon flow to ethanol formation. CONCLUSIONS:We systematically characterized and optimized the PDCzm-slr1192 pathway in engineered cyanobacteria for ethanol production. Information gained from in vitro monitoring and genetic engineering revealed that for further enhancing ethanol synthesis capacities, PDCzm activities needed enhancement, and the PDCzm-slr1192 ratio should be improved and held to about 1:1.5. Considering actual metabolites concentrations of cyanobacteria cells, enhancing pyruvate supply was also a promising strategy for further updating the current ethanol photosynthetic cell factories.
journal_name
Biotechnol Biofuelsjournal_title
Biotechnology for biofuelsauthors
Luan G,Qi Y,Wang M,Li Z,Duan Y,Tan X,Lu Xdoi
10.1186/s13068-015-0367-zsubject
Has Abstractpub_date
2015-11-21 00:00:00pages
184issn
1754-6834pii
367journal_volume
8pub_type
杂志文章abstract:Background:Cyanobacteria are ideal model organisms to exploit photosynthetically derived electrons or fixed carbon for the biotechnological synthesis of high value compounds and energy carriers. Much effort is spent on the rational design of heterologous pathways to produce value-added chemicals. Much less focus is dra...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-019-1378-y
更新日期:2019-02-27 00:00:00
abstract:BACKGROUND:Furfural is the prevalent microbial inhibitor generated during pretreatment and hydrolysis of lignocellulose biomass to monomeric sugars, but the response of acetone butanol ethanol (ABE) producing Clostridium beijerinckii NCIMB 8052 to this compound at the molecular level is unknown. To discern the effect o...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/1754-6834-6-66
更新日期:2013-05-04 00:00:00
abstract::Biorefineries, designed for the production of lignocellulose-based chemicals and fuels, are receiving increasing attention from the public, governments, and industries. A major obstacle for biorefineries to advance to commercial scale is the high cost of the enzymes required to derive the fermentable sugars from the f...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章,评审
doi:10.1186/s13068-019-1571-z
更新日期:2019-10-08 00:00:00
abstract:Background:Cyanobacteria have shown promising potential for the production of various biofuels and chemical feedstocks. Synechococcus elongatus UTEX 2973 is a fast-growing strain with pronounced tolerance to high temperatures and illumination. Hence, this strain appears to be ideal for the development of photosynthetic...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-018-1215-8
更新日期:2018-08-04 00:00:00
abstract:BACKGROUND:Volatile fatty acids (VFA) are building blocks for the chemical industry. Sustainable, biological production is constrained by production and recovery costs, including the need for intensive pH correction. Membrane electrolysis has been developed as an in situ extraction technology tailored to the direct rec...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-015-0396-7
更新日期:2015-12-21 00:00:00
abstract:Background:The recombinant Saccharomyces cerevisiae strains that acquired the ability to utilize xylose through metabolic and evolutionary engineering exhibit good performance when xylose is the sole carbon source in the medium (designated the X stage in the present work). However, the xylose consumption rate of strain...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-018-1112-1
更新日期:2018-04-16 00:00:00
abstract:BACKGROUND:In addition to efficient pentose utilization, high inhibitor tolerance is a key trait required in any organism used for economically viable industrial bioethanol production with lignocellulose biomass. Although recent work has succeeded in establishing efficient xylose fermentation in robust industrial Sacch...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/1754-6834-6-120
更新日期:2013-08-26 00:00:00
abstract:BACKGROUND:Glycoside hydrolases are important for various industrial and scientific applications. Determination of their temperature as well as pH optima and range is crucial to evaluate whether an enzyme is suitable for application in a biotechnological process. These basic characteristics of enzymes are generally det...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-017-0923-9
更新日期:2017-10-11 00:00:00
abstract:BACKGROUND:Recently developed iron cocatalyst enhancement of dilute acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. In the current study, our aim was to identify...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/1754-6834-4-48
更新日期:2011-11-10 00:00:00
abstract:BACKGROUND:The production of biofuels and biochemicals from grass-type plant biomass requires a complete utilisation of the plant cellulose and hemicellulosic xylan via enzymatic degradation to their constituent monosaccharides. Generally, physical and/or thermochemical pretreatments are performed to enable access for ...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-016-0519-9
更新日期:2016-05-18 00:00:00
abstract:Background:Amelioration of biofuel feedstock of microalgae using sustainable means through synthetic ecology is a promising strategy. The co-cultivation model (Tetraselmis striata and Pelagibaca bermudensis) was evaluated for the robust biofuel production under varying stressors as well as with the selected two-stage c...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-018-1097-9
更新日期:2018-04-07 00:00:00
abstract:BACKGROUND:Microalgae are highly efficient cellular factories that capture CO2 and are also alternative feedstock for biofuel production. Carbohydrates, proteins, and lipids are major biochemical components in microalgae. Carbohydrates or starch in microalgae are possible substrates in yeast fermentation for biofuel pr...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-017-0753-9
更新日期:2017-03-24 00:00:00
abstract:Background:Methane, a main component of natural gas and biogas, has gained much attention as an abundant and low-cost carbon source. Methanotrophs, which can use methane as a sole carbon and energy source, are promising hosts to produce value-added chemicals from methane, but their metabolic engineering is still challe...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-019-1574-9
更新日期:2019-09-30 00:00:00
abstract:BACKGROUND:When producing biofuels from dedicated feedstock, agronomic factors such as harvest time and location can impact the downstream production. Thus, this paper studies the effectiveness of ammonia fibre expansion (AFEX) pretreatment on two harvest times (July and October) and ecotypes/locations (Cave-in-Rock (C...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/1754-6834-3-1
更新日期:2010-01-04 00:00:00
abstract::Microalgae hold great promises as sustainable cellular factories for the production of alternative fuels, feeds, and biopharmaceuticals for human health. While the biorefinery approach for fuels along with the coproduction of high-value compounds with industrial, therapeutic, or nutraceutical applications have the pot...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章,评审
doi:10.1186/s13068-019-1635-0
更新日期:2019-12-23 00:00:00
abstract:Background:Acid pretreatment is a common strategy used to break down the hemicellulose component of the lignocellulosic biomass to release pentoses, and a subsequent enzymatic hydrolysis step is usually applied to release hexoses from the cellulose. The hydrolysate after pretreatment and enzymatic hydrolysis containing...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-020-01781-1
更新日期:2020-08-13 00:00:00
abstract:UNLABELLED: BACKGROUND:Acetoin and 2,3-butanediol are two important biorefinery platform chemicals. They are currently fermented below 40°C using mesophilic strains, but the processes often suffer from bacterial contamination. RESULTS:This work reports the isolation and identification of a novel aerobic Geobacillus s...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/1754-6834-5-88
更新日期:2012-12-06 00:00:00
abstract:BACKGROUND:Microbial lipid production using renewable feedstock shows great promise for the biodiesel industry. RESULTS:In this study, the ability of a lipid-engineered Yarrowia lipolytica strain JMY4086 to produce lipids using molasses and crude glycerol under different oxygenation conditions and at different inoculu...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-015-0286-z
更新日期:2015-07-25 00:00:00
abstract:BACKGROUND:Alcohol-to-jet (ATJ) is one of the technical feasible biofuel technologies. It produces jet fuel from sugary, starchy, and lignocellulosic biomass, such as sugarcane, corn grain, and switchgrass, via fermentation of sugars to ethanol or other alcohols. This study assesses the ATJ biofuel production pathway f...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-017-0702-7
更新日期:2017-01-19 00:00:00
abstract:BACKGROUND:Oleaginous microorganisms are attractive feedstock for production of liquid biofuels. Direct hydrothermal liquefaction (HTL) is an efficient route that converts whole, wet biomass into an energy-dense liquid fuel precursor, called 'biocrude'. HTL represents a promising alternative to conventional lipid extra...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-015-0345-5
更新日期:2015-10-13 00:00:00
abstract:BACKGROUND:Environmental crisis and concerns for energy security have made the research for renewable fuels that will substitute the usage of fossil fuels an important priority. Biodiesel is a potential substitute for petroleum, but its feasibility is hindered by the utilization of edible vegetable oil as raw material,...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-014-0190-y
更新日期:2015-01-22 00:00:00
abstract:BACKGROUND:Engineering of the yeast Saccharomyces cerevisiae for improved utilization of pentose sugars is vital for cost-efficient cellulosic bioethanol production. Although endogenous hexose transporters (Hxt) can be engineered into specific pentose transporters, they remain subjected to glucose-regulated protein deg...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-016-0573-3
更新日期:2016-07-26 00:00:00
abstract:BACKGROUND:Inefficient carbohydrate conversion has been an unsolved problem for various lignocellulosic biomass pretreatment technologies, including AFEX, dilute acid, and ionic liquid pretreatments. Previous work has shown 22% of total carbohydrates are typically unconverted, remaining as soluble or insoluble oligomer...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-017-0757-5
更新日期:2017-03-29 00:00:00
abstract:BACKGROUND:Production of valuable metabolites by Yarrowia lipolytica using renewable raw materials is of major interest for sustainable food and energy. Galactose is a monosaccharide found in galactomannans, hemicelluloses, gums, and pectins. RESULTS:Yarrowia lipolytica was found to express all the Leloir pathway gene...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-015-0370-4
更新日期:2015-11-25 00:00:00
abstract:Background:2,3-Butanediol (2,3-BDO) is a valuable chemical for industrial applications. Bacteria can produce 2,3-BDO with a high productivity, though most of their classification as pathogens makes them undesirable for the industrial-scale production. Though Saccharomyces cerevisiae (GRAS microorganism) was engineered ...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-019-1545-1
更新日期:2019-08-29 00:00:00
abstract:: The production of cellulosic ethanol from biomass is considered a promising alternative to reliance on diminishing supplies of fossil fuels, providing a sustainable option for fuels production in an environmentally compatible manner. The conversion of lignocellulosic biomass to biofuels through a biological route usu...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/1754-6834-6-15
更新日期:2013-01-28 00:00:00
abstract:Background:Triacylglycerols (TAGs) rich in medium-chain fatty acids (MCFAs, C10-14 fatty acids) are valuable feedstocks for biofuels and chemicals. Natural sources of TAGs rich in MCFAs are restricted to a limited number of plant species, which are unsuitable for mass agronomic production. Instead, the modification of ...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-018-1177-x
更新日期:2018-06-25 00:00:00
abstract:Background:To increase the production of bioethanol, a two-step process based on hydrothermal and dilute alkaline treatment was applied to reduce the natural resistance of biomass. However, the process required a large amount of water and a long operation time due to the solid/liquid separation before the alkaline trea...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-018-1140-x
更新日期:2018-05-12 00:00:00
abstract:BACKGROUND:The 'attached cultivation' technique for microalgae production, combining the immobilized biofilm technology with proper light dilution strategies, has shown improved biomass production and photosynthetic efficiency over conventional open-pond suspended cultures. However, how light is transferred and distrib...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/s13068-015-0240-0
更新日期:2015-03-26 00:00:00
abstract:BACKGROUND:Non-productive cellulase adsorption onto lignin has always been deemed to negatively affect the enzymatic hydrolysis of lignocellulosic feedstocks. Therefore, understanding enzyme-lignin interactions is essential for the development of enzyme mixtures, the processes of lignocellulose hydrolysis, and the gene...
journal_title:Biotechnology for biofuels
pub_type: 杂志文章
doi:10.1186/1754-6834-7-38
更新日期:2014-03-14 00:00:00