Biochar is increasingly proposed as a soil amendment, with reports of benefits to soil physical, chemical and biological properties. In this study, different biochars were produced from 6 feedstocks, including straw a...Biochar is increasingly proposed as a soil amendment, with reports of benefits to soil physical, chemical and biological properties. In this study, different biochars were produced from 6 feedstocks, including straw and poultry manure, at 3 pyrolysis temperatures （200, 300 and 500℃） and then added separately to a calcareous soil. Their effects on soil properties and maize growth were evaluated in a pot experiment. The biochars derived from crop straw had much higher C but smaller N concentrations than those derived from poultry manure. Carbon concentrations, pH and EC values increased with increasing pyrolysis temperature. Biochar addition resulted in increases in mean maize dry matter of 12.73% and NPK concentrations of 30, 33 and 283%, respectively. Mean soil pH values were increased by 0.45 units. The biochar-amended soils had 44, 55, 254 and 537% more organic C, total N, Olsen-P and available K, respectively, than the control on average. Both feedstocks and pyrolysis temperature determined the characteristics of the biochar. Biochars with high mineral concentrations may act as mineral nutrient supplements.展开更多
The rheological behaviors of feedstocks for powder extrusion molding, in the temperature range of 40～80 ℃ and the Newton shear rate of 3～800 s -1 , were studied. The effects of feedstock constitution, shear rate an...The rheological behaviors of feedstocks for powder extrusion molding, in the temperature range of 40～80 ℃ and the Newton shear rate of 3～800 s -1 , were studied. The effects of feedstock constitution, shear rate and temperature on apparent viscosity, shear stress and active energy were investigated. The viscose flow active energy of PEM feedstocks is 15.89～90.77 kJ/mol. Based on this research, the PEM technical parameters have optimized. [展开更多
L-malate is an intermediate of the tricarboxylic acid cycle which is naturally occurred in various microorganisms,and it has been widely applied in polymer,beverage and food,textile,agricultural and pharmaceutical ind...L-malate is an intermediate of the tricarboxylic acid cycle which is naturally occurred in various microorganisms,and it has been widely applied in polymer,beverage and food,textile,agricultural and pharmaceutical industries.Driven by the pursuit of a sustainable economy,microbial production of L-malate has received much attention in last decades.In this review,we focus on the utilization of wastes and/or byproducts as feedstocks for the microbial production of L-malate.Firstly,we present the recent developments on the natural or engineered metabolic pathways that dedicate to the biosynthesis of L-malate,and also provide a comprehensive discussions on developing high-efficient producers.Then,the recent achievements in microbial production of L-malate from various carbon sources were concluded and discussed.Furthermore,some abundant non-food feedstocks which have been used for microbial production of other chemicals were reviewed,as they may be potential candidate feedstock for L-malate production in future.Finally,we outlined the major challenges and proposed further improvements for the production of L-malate.展开更多
Terpenoids are a diverse class of natural products widely used as pharmaceuticals,perfumes,flavors,and biofuels.Traditionally,terpenoids are obtained from natural sources,such as plants,but their production is limited...Terpenoids are a diverse class of natural products widely used as pharmaceuticals,perfumes,flavors,and biofuels.Traditionally,terpenoids are obtained from natural sources,such as plants,but their production is limited by the insufficiency of resources and low yields of extraction.Microbial production of terpenoids has emerged as a promising alternative due to that it is sustainable and easy to scale up.This review aims to summarize recent advances in microbial production of terpenoids from inexpensive biomass-derived feedstocks.Metabolic pathways and key enzymes involved in terpenoid biosynthesis are introduced.Microorganisms that can utilize low-cost lignocellulosic feedstocks for terpenoid production are highlighted.The challenges and prospects faced by microbial terpenoid production are proposed.We believe that continuous progress in the fields of biomass transformation and synthetic biology will ultimately achieve industrial production of microbial terpenoids.展开更多
The use of abundant and cheap one carbon(C1)feedstocks to produce value-added chemicals is an important approach for achieving carbon neutrality and tackling environmental problems.The conversion of C1 feedstocks to h...The use of abundant and cheap one carbon(C1)feedstocks to produce value-added chemicals is an important approach for achieving carbon neutrality and tackling environmental problems.The conversion of C1 feedstocks to high-value chemicals is dependent on efficient C1 assimilation pathways and microbial chassis adapted for efficient incorporation.Here,we opted to summarize the natural and synthetic C1 assimilation pathways and their key factors for metabolizing C1 feedstock.Accordingly,we discussed the metabolic engineering strategies for enabling the microbial utilization of C1 feedstocks for the bioproduction of value-added chemicals.In addition,we highlighted future perspectives of C1-based biomanufacturing for achieving a low-carbon footprint for the biosynthesis of chemicals.展开更多
The main feedstocks for bioethanol are sugarcane （Saccharum offic- inarum） and maize （Zea mays）, both of which are C4 grasses, highly efficient at converting solar energy into chemical energy, and both are food cr...The main feedstocks for bioethanol are sugarcane （Saccharum offic- inarum） and maize （Zea mays）, both of which are C4 grasses, highly efficient at converting solar energy into chemical energy, and both are food crops. As the systems for lignocellulosic bioethanol production become more efficient and cost effective, plant biomass from any source may be used as a feedstock for bioethanol production. Thus, a move away from using food plants to make fuel is possible, and sources of biomass such as wood from forestry and plant waste from cropping may be used. However, the bioethanol industry will need a continuous and reliable supply of biomass that can be produced at a low cost and with minimal use of water, fertilizer and arable land. As many C4 plants have high light, water and nitrogen use efficiency, as compared with C3 species, they are ideal as feedstock crops. We consider the productivity and resource use of a number of candidate plant species, and discuss biomass ＇quality＇, that is, the composition of the plant cell wall.展开更多
Metal matrix composites(MMCs)are frequently employed in various advanced industries due to their high modulus and strength,favorable wear and corrosion resistance,and other good properties at elevated temperatures.In ...Metal matrix composites(MMCs)are frequently employed in various advanced industries due to their high modulus and strength,favorable wear and corrosion resistance,and other good properties at elevated temperatures.In recent decades,additive manufacturing(AM)technology has garnered attention as a potential way for fabricating MMCs.This article provides a comprehensive review of recent endeavors and progress in AM of MMCs,encompassing available AM technologies,types of reinforcements,feedstock preparation,synthesis principles during the AM process,typical AM-produced MMCs,strengthening mechanisms,challenges,and future interests.Compared to conventionally manufactured MMCs,AM-produced MMCs exhibit more uniformly distributed reinforcements and refined microstructure,resulting in comparable or even better mechanical properties.In addition,AM technology can produce bulk MMCs with significantly low porosity and fabricate geometrically complex MMC components and MMC lattice structures.As reviewed,many AM-produced MMCs,such as Al matrix composites,Ti matrix composites,nickel matrix composites,Fe matrix composites,etc,have been successfully produced.The types and contents of reinforcements strongly influence the properties of AM-produced MMCs,the choice of AM technology,and the applied processing parameters.In these MMCs,four primary strengthening mechanisms have been identified:Hall–Petch strengthening,dislocation strengthening,load transfer strengthening,and Orowan strengthening.AM technologies offer advantages that enhance the properties of MMCs when compared with traditional fabrication methods.Despite the advantages above,further challenges of AM-produced MMCs are still faced,such as new methods and new technologies for investigating AM-produced MMCs,the intrinsic nature of MMCs coupled with AM technologies,and challenges in the AM processes.Therefore,the article concludes by discussing the challenges and future interests of AM of MMCs.展开更多
Metabolic engineering to produce tricarboxylic acid(TCA)cycle-derived chemicals is usually associated with problems of low production yield and impaired cellular metabolism.In this work,we found that fatty acid(FA)fee...Metabolic engineering to produce tricarboxylic acid(TCA)cycle-derived chemicals is usually associated with problems of low production yield and impaired cellular metabolism.In this work,we found that fatty acid(FA)feedstocks could enable high-yield production of TCA cycle-derived chemicals,while maintaining an efficient and balanced metabolic flux of the glyoxylate-TCA cycle,which is favorable for both product synthesis and cell growth.Here,we designed a novel synthetic pathway for production of β-alanine,an important TCA cycle-derived product,from FAs with a high theortecial yield of 1.391 g/g.By introducing panD,improving aspA,and knocking out iclR,glyoxylate shunt was highly activated in FAs and the yield of β-alanine reached 0.71 g/g from FAs,much higher than from glucose.Blocking the TCA cycle at icd/sucA/fumAC nodes could increase β-alanine yield in a flask cultivation,but severely reduced cell growth and FA utilization during fed-batch processes.Replenishing oxaloacetate by knocking out aspC and recovering fumAC could restore the growth and lead to a titer of 35.57 g/l.After relieving the oxidative stress caused by FA metabolism,β-alanine production could reach 72.05 g/l with a maximum yield of 1.24 g/g,about 86% of the theoretical yield.Our study thus provides a promising strategy for the production of TCA cycle-derived chemicals.展开更多
In the usage phase,diesel engines fuelled with diesel-biodiesel blends produced lower soot,HC and CO emissions.However,the environmental effects should include the greenhouse gas(GHG)emissions.GHG variations of biodie...In the usage phase,diesel engines fuelled with diesel-biodiesel blends produced lower soot,HC and CO emissions.However,the environmental effects should include the greenhouse gas(GHG)emissions.GHG variations of biodiesel production from three generation feedstocks were analyzed based on the land use change(LUC).Adequate land use change could keep the biodiversity and did not cause the increase of GHG emissions.The choice for feedstocks of biodiesel in China was comprehensively analyzed based on the land use type,the precipitation and the oil contents and the cultivation conditions of plants.Then,the suggestions for biodiesel development in China were given.Results showed that China should thoroughly abandon the first generation feedstocks due to the lack of arable land.Jatropha curcas(J.curcas),Pistacia chinensis Bunge(P.chinensis),Comus wilsoniana(C.wilsoniana)and Xanthoceras sorbifolium Bunge(X.sorbifolium)were considered as the most promising feedstocks for biodiesel production.It is suggested to plant X.sorbifolium in sand lands in the north and northwest of China with less natural rainfall and the others in south and southwest of China.The concern for microalgae should be transmitted to engineering microalgae cultivated in wastewater.The microalgae biodiesel refinery should be developed together with wastewater proposal industry and coal fired power plants.Lastly,only natural gas-based or biomass-based methanol can be used for biodiesel production.展开更多
Satellited CoNiCrAlY–Al_(2)O_(3)feedstocks with 2wt%, 4wt%, and 6wt% oxide nanoparticles and pure CoNiCrAlY powder were deposited by the high-velocity oxy fuel process on an Inconel738 superalloy substrate. The oxida...Satellited CoNiCrAlY–Al_(2)O_(3)feedstocks with 2wt%, 4wt%, and 6wt% oxide nanoparticles and pure CoNiCrAlY powder were deposited by the high-velocity oxy fuel process on an Inconel738 superalloy substrate. The oxidation test was performed at 1050℃ for 5, 50, 100,150, 200, and 400 h. The microstructure and phase composition of powders and coatings were characterized by scanning electron microscopy and X-ray diffraction, respectively. The bonding strength of the coatings was also evaluated. The results proved that with the increase in the percentage of nanoparticles(from 2wt% to 6wt%), the amount of porosity(from 1vol% to 4.7vol%), unmelted particles, and roughness of the coatings(from 4.8 to 8.8 μm) increased, and the bonding strength decreased from 71 to 48 MPa. The thicknesses of the thermally grown oxide layer of pure and composite coatings(2wt%, 4wt%, and 6wt%) after 400 h oxidation were measured as 6.5, 5.5, 7.6, and 8.1 μm, respectively.The CoNiCrAlY–2wt% Al_(2)O_(3)coating showed the highest oxidation resistance due to the diffusion barrier effect of well-dispersed nanoparticles. The CoNiCrAlY–6wt% Al_(2)O_(3)coating had the lowest oxidation resistance due to its rough surface morphology and porous microstructure.展开更多
The upgrading of diesel oil to produce ethylene rich cracking feedstock is an important and promising technical route to reduce the ratio of diesel to gasoline. In the present work, a hydrocracking catalyst suitable f...The upgrading of diesel oil to produce ethylene rich cracking feedstock is an important and promising technical route to reduce the ratio of diesel to gasoline. In the present work, a hydrocracking catalyst suitable for selective hydrocracking of straight run diesel oil to produce high-quality ethylene cracking feedstock at low cost was developed, by optimizing the composition of catalyst support materials, using amorphous silicon aluminum and aluminum oxide with high mesopore content as the main support, and modified Y zeolite with excellent aromatic ring opening selectivity as the acidic component. The catalyst has in-depth characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N<sub>2</sub>-low temperature adsorption-desorption, NH<sub>3</sub>-temperature-programmed desorption, and IR techniques. And its catalytic cracking straight run diesel oil performance was evaluated. The results show that the prepared catalyst has high polycyclic aromatic hydrocarbon ring opening cracking selectivity. However, alkanes retained in diesel distillates can achieve the goal of producing more ethylene cracking feedstocks with low BMCI value under low and moderate pressure conditions. This work may shed significant technical insight for oil refining transformation.展开更多
Ti-6Al-4V alloy powder was taken as raw material. 60%（mass fraction） paraffin, 35%low density polyethylene and 5%stearic acid were employed as binders to prepare injection feedstocks. Capillary rheometer was adopted...Ti-6Al-4V alloy powder was taken as raw material. 60%（mass fraction） paraffin, 35%low density polyethylene and 5%stearic acid were employed as binders to prepare injection feedstocks. Capillary rheometer was adopted to determine the rheological parameters and to analyze the rheological properties of the feedstocks at different milling time, powder loading and temperature. It is indicated through the results that the viscosity increases and the value of n decreases with the increase of milling time. The more the powder loading is, the higher the viscosity is. The empirical formula on the relationship between the viscosity and the powder loading is： ηr=η/ηb=A（1-Ф/Фmax）/^- m . The value m is calculated as 0.33. The flow activation energy Ea decreases with the increase of shear rate.展开更多
This work reports the preparation of bulk and KIT-6-diluted W-Nb-O mixed oxide bronzes by a reflux method. The influence of the incorporation of Nb and a mesoporous silica on the physicochemical features of the cataly...This work reports the preparation of bulk and KIT-6-diluted W-Nb-O mixed oxide bronzes by a reflux method. The influence of the incorporation of Nb and a mesoporous silica on the physicochemical features of the catalysts is studied. The addition of Nb favors the formation of single-phase oxide bronze structure, with improved Lewis acidity;while the incorporation of KIT-6 gives rise to well-dispersed mixed metal oxide particles on the diluter. These diluted W-Nb-O catalysts present enhanced surface areas and mesopore volumes. The materials have been tested in the valorization of an aqueous model mixture (acetol/propanal/ethanol/acetic acid/water weight ratio of 5/25/10/30/30), through C-C bond formation reactions. The increase in the Lewis nature of surface acid sites stands as the key point to maximize the total organic yield during the reaction (C5-C10 products). The best catalysts maintain their catalytic behavior after five consecutive uses.展开更多
3D Euler double-fluid model was applied and three different feedstocks and reverts formations were simulated. By calculating and analyzing the state of gas and solid fluxion in absorber using three different methods o...3D Euler double-fluid model was applied and three different feedstocks and reverts formations were simulated. By calculating and analyzing the state of gas and solid fluxion in absorber using three different methods of the feedstocks and reverts in recirculating fluidized bed, described the behavior of gas and solid through the gas-phase velocity, turbulence intensity, gas-solid sliding velocity, and density of particles. The results show that the feedstocks and reverts enters into absorption tower through two symmetrical feedings and are mixed with flue gas. Based on the respective analysis of each model and the com- parison analysis of the three models, this paper drew conclusions. The turbulence intensity of absorption tower is high, gas-solid sliding speed is big, and granule concentration near the axis is high, which has advantages for desulfurization and im- proving the utilization rate of absorbent.展开更多
This paper describes a brief review of biodiesel R & D developmental trends at Tarbiat Modares University (TMU) bio- energy research laboratories (lab.), Tehran, Iran. The developmental trends at includes potentia...This paper describes a brief review of biodiesel R & D developmental trends at Tarbiat Modares University (TMU) bio- energy research laboratories (lab.), Tehran, Iran. The developmental trends at includes potential and feasibility study, cultivation of a sample bioenrgy farm, technology innovation and its scale up (patents) for fuel processing, and finally the fuel application in diesel engines. A national investigation was carried out to find out the possible potential of sustainable feedstock for biodiesel production. The results showed that easily available biodiesel feedstock is waste cooking oil with a maximum potential of 750 mil.lit and an approximately 350 mil.lit. of collectable waste cooking oil. A castor oil plant farm was cultivated to harvest castor plant seeds, extract its oil, produce biodiesel fuel and use it in diesel engines. This led to a series of patent and consequently technology innovation from 7 lit. lab. scale to semi-continuous, semi-industrial scale of 2 ton capacity.展开更多
A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well document...A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well documented, but information is lacking for sweet sorghum. Three and six commercial cultivars of sugarcane and sweet sorghum, respectively, were selected and evaluated for exposure to a late fall frost (-2.8°C) in Griffin, Georgia, USA. Under the same controlled environmental conditions in a screen house, the late fall frost induced more damage to sugarcane than sweet sorghum stems. The frost caused damage to sugarcane tissue and for juice to exude from stems, whereas similar behavior was not observed for sweet sorghum. In both sugarcane and sweet sorghum, the glucose/fructose ratio was significantly reduced, but this change may not be totally directly related to the frost effect. Overall, these initial results suggest that sweet sorghum may have a better tolerance to fall frost than sugarcane. Two sweet sorghum cultivars, Grassl and M81E, responded well to the late fall frost, and they can possibly be used as feedstocks for biofuel/bioproduct manufacture in areas susceptible to frosts including northern regions of the Southeastern US.展开更多
Biodiesel utilization has been rapidly growing worldwide as the prime alternative to petrodiesel due to a global rise in diesel fuel demand along with hazardous emissions during its thermochemical conversion.Although,...Biodiesel utilization has been rapidly growing worldwide as the prime alternative to petrodiesel due to a global rise in diesel fuel demand along with hazardous emissions during its thermochemical conversion.Although,several debatable issues including feedstock availability and price,fuel and food competition,changes in land use and greenhouse gas emission have been raised by using edible as well as inedible feedstocks for the production of biodiesel.However,non-crop feedstocks could be a promising alternative.In this article,waste cooking oils have been recommended as a suitable option for biodiesel production bearing in mind the current national situation.The important factors such as the quantity of waste cooking oil produced,crude oil and vegetable oil import expenses,high-speed diesel imports,waste management issues and environmental hazards are considered.Moreover,process simulation and operating cost evaluation of an acid catalyzed biodiesel production unit are also conducted.The simulation results show that the production cost of waste cooking oil-based biodiesel is about 0.66 USD·L-1.We believe that the present overview would open new pathways and ideas for the development of biofuels from waste to energy approach in Pakistan.展开更多
The vegetable wastes and flower stems were co-digested to evaluate the anaerobic hydrolysis performance of difficultly biodegradable organic wastes by introducing readily biodegradable organic wastes. The experiments ...The vegetable wastes and flower stems were co-digested to evaluate the anaerobic hydrolysis performance of difficultly biodegradable organic wastes by introducing readily biodegradable organic wastes. The experiments were carried out in batches. When the vegetable wastes were mixed with the flower stems at the dry weight ratio of 1 to 13, the overall hydrolysis rate increased by 8%, 12%, and 2% according to the carbon, nitrogen, and total solid （TS） conversion rate, respectively. While the dry weight ratio was designed as 1 to 3, there was a respective rise of 5%, 15%, and 4% in the conversion rate of carbon, nitrogen, and TS. The enhancement of anaerobic hydrolysis from the mixed vegetable wastes and flower stems can be attributed to the formation of volatile fatty acids （VFA） and nutrient supplement like nitrogen content. The maximum VFA concentration can achieve 1.7 g/L owing to the rapid acidification of vegetable wastes, loosing the structure of lignocellulose materials. The statistic bivariate analysis revealed that the hydrolysis performance was significantly related to the physical and biochemical compositions of the feeding substrate. Especially, the soluble carbon concentration in the liquid was significantly positively correlated to the concentration of nitrogen and hemicellulose, and negatively correlated to the concentration of carbon and lignocellulose in the feeding substrate, suggesting that the regulation and control of feedstock can have an important influence on the anaerobic hydrolysis of organic wastes.展开更多
Based on the analysis of flow characteristics of the FCC riser feedstock injection zone, two novel feedstock injection structures are put forward. By investigating three flow parameters in the feedstock injection zone...Based on the analysis of flow characteristics of the FCC riser feedstock injection zone, two novel feedstock injection structures are put forward. By investigating three flow parameters in the feedstock injection zone under the three different structures (the traditional and the novel No. 1, No. 2 structures): the local density, the particle backmixng ratio, and the jet eigen-concentration, the flow feature under three structures were obtained. The experimental results demonstrate that the flow features under both proposed structures are obviously improved comparing with those under the traditional structure. Especially, the performance of the deflector-structured No. 2 is more desirable than that of No. 1.展开更多
Nanocrystalline NiCrC alloy powders with a qualified particle size distribution for thermal spraying were synthesized using the cryogenic ball milling （cryomilling） method. The morphology, microstructure, size distr...Nanocrystalline NiCrC alloy powders with a qualified particle size distribution for thermal spraying were synthesized using the cryogenic ball milling （cryomilling） method. The morphology, microstructure, size distribution, and phase transformation of the powders were characterized by scanning electron microscopy （SEM）, laser scattering for particle size analysis, X-ray diffraction （XRD）, and transmission electron microscopy （TEM）. After cryomilling for 20 h, the average grain size of the as-milled powders approached a constant value of 30 nm by XRD measurement. The average particle size slightly increased from 17.5 to 20.3 μm during the 20-h milling. About 90vol% of the powders satisfied the requirement for thermal spraying with the particle dimension of 10-50 μm, and most of the powders exhibited spherical morphology, which were expected to have good fluidity during thermal spraying. The Cr2O3 phase formed during the cryornilling process as revealed in the XRD spectra, which was expected to enhance the thermal stability of the as-milled powders during the followed thermal spraying or other heat treatment.展开更多
基金supported by the National Natural Science Foundation of China (41171211)the Special Fund for Agro-Scientific Research in the Public Interest, China (201303095-2)
文摘Biochar is increasingly proposed as a soil amendment, with reports of benefits to soil physical, chemical and biological properties. In this study, different biochars were produced from 6 feedstocks, including straw and poultry manure, at 3 pyrolysis temperatures （200, 300 and 500℃） and then added separately to a calcareous soil. Their effects on soil properties and maize growth were evaluated in a pot experiment. The biochars derived from crop straw had much higher C but smaller N concentrations than those derived from poultry manure. Carbon concentrations, pH and EC values increased with increasing pyrolysis temperature. Biochar addition resulted in increases in mean maize dry matter of 12.73% and NPK concentrations of 30, 33 and 283%, respectively. Mean soil pH values were increased by 0.45 units. The biochar-amended soils had 44, 55, 254 and 537% more organic C, total N, Olsen-P and available K, respectively, than the control on average. Both feedstocks and pyrolysis temperature determined the characteristics of the biochar. Biochars with high mineral concentrations may act as mineral nutrient supplements.
文摘The rheological behaviors of feedstocks for powder extrusion molding, in the temperature range of 40～80 ℃ and the Newton shear rate of 3～800 s -1 , were studied. The effects of feedstock constitution, shear rate and temperature on apparent viscosity, shear stress and active energy were investigated. The viscose flow active energy of PEM feedstocks is 15.89～90.77 kJ/mol. Based on this research, the PEM technical parameters have optimized. [
基金This work was supported by the National Key R&D Program of China(2018YFA0901500)the National Natural Science Foundation of China(21706124,21727818)+1 种基金the Key Science and Technology Project of Jiangsu Province(BE2016389)the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture of China.
文摘L-malate is an intermediate of the tricarboxylic acid cycle which is naturally occurred in various microorganisms,and it has been widely applied in polymer,beverage and food,textile,agricultural and pharmaceutical industries.Driven by the pursuit of a sustainable economy,microbial production of L-malate has received much attention in last decades.In this review,we focus on the utilization of wastes and/or byproducts as feedstocks for the microbial production of L-malate.Firstly,we present the recent developments on the natural or engineered metabolic pathways that dedicate to the biosynthesis of L-malate,and also provide a comprehensive discussions on developing high-efficient producers.Then,the recent achievements in microbial production of L-malate from various carbon sources were concluded and discussed.Furthermore,some abundant non-food feedstocks which have been used for microbial production of other chemicals were reviewed,as they may be potential candidate feedstock for L-malate production in future.Finally,we outlined the major challenges and proposed further improvements for the production of L-malate.
基金the National Key Research and Development Program of China(No.2022YFC2104700).
文摘Terpenoids are a diverse class of natural products widely used as pharmaceuticals,perfumes,flavors,and biofuels.Traditionally,terpenoids are obtained from natural sources,such as plants,but their production is limited by the insufficiency of resources and low yields of extraction.Microbial production of terpenoids has emerged as a promising alternative due to that it is sustainable and easy to scale up.This review aims to summarize recent advances in microbial production of terpenoids from inexpensive biomass-derived feedstocks.Metabolic pathways and key enzymes involved in terpenoid biosynthesis are introduced.Microorganisms that can utilize low-cost lignocellulosic feedstocks for terpenoid production are highlighted.The challenges and prospects faced by microbial terpenoid production are proposed.We believe that continuous progress in the fields of biomass transformation and synthetic biology will ultimately achieve industrial production of microbial terpenoids.
基金supported by the Provincial Outstanding Youth Foundation of Jiangsu Province(BK20211529)the National Science Fund for Excellent Young Scholars(22122806)the Fundamental Research Funds for the Central Universities(JUSRP22031).
文摘The use of abundant and cheap one carbon(C1)feedstocks to produce value-added chemicals is an important approach for achieving carbon neutrality and tackling environmental problems.The conversion of C1 feedstocks to high-value chemicals is dependent on efficient C1 assimilation pathways and microbial chassis adapted for efficient incorporation.Here,we opted to summarize the natural and synthetic C1 assimilation pathways and their key factors for metabolizing C1 feedstock.Accordingly,we discussed the metabolic engineering strategies for enabling the microbial utilization of C1 feedstocks for the bioproduction of value-added chemicals.In addition,we highlighted future perspectives of C1-based biomanufacturing for achieving a low-carbon footprint for the biosynthesis of chemicals.
基金supported by the Australian Research Council (ARC) though ARC-linkage project LP0883808
文摘The main feedstocks for bioethanol are sugarcane （Saccharum offic- inarum） and maize （Zea mays）, both of which are C4 grasses, highly efficient at converting solar energy into chemical energy, and both are food crops. As the systems for lignocellulosic bioethanol production become more efficient and cost effective, plant biomass from any source may be used as a feedstock for bioethanol production. Thus, a move away from using food plants to make fuel is possible, and sources of biomass such as wood from forestry and plant waste from cropping may be used. However, the bioethanol industry will need a continuous and reliable supply of biomass that can be produced at a low cost and with minimal use of water, fertilizer and arable land. As many C4 plants have high light, water and nitrogen use efficiency, as compared with C3 species, they are ideal as feedstock crops. We consider the productivity and resource use of a number of candidate plant species, and discuss biomass ＇quality＇, that is, the composition of the plant cell wall.
基金the financial support from the Australian Research Council through the Discovery Project(DP110101653 and DP130103592)Basic and Applied Basic Research Foundation of Guangdong Province,China(2022A1515140123).
文摘Metal matrix composites(MMCs)are frequently employed in various advanced industries due to their high modulus and strength,favorable wear and corrosion resistance,and other good properties at elevated temperatures.In recent decades,additive manufacturing(AM)technology has garnered attention as a potential way for fabricating MMCs.This article provides a comprehensive review of recent endeavors and progress in AM of MMCs,encompassing available AM technologies,types of reinforcements,feedstock preparation,synthesis principles during the AM process,typical AM-produced MMCs,strengthening mechanisms,challenges,and future interests.Compared to conventionally manufactured MMCs,AM-produced MMCs exhibit more uniformly distributed reinforcements and refined microstructure,resulting in comparable or even better mechanical properties.In addition,AM technology can produce bulk MMCs with significantly low porosity and fabricate geometrically complex MMC components and MMC lattice structures.As reviewed,many AM-produced MMCs,such as Al matrix composites,Ti matrix composites,nickel matrix composites,Fe matrix composites,etc,have been successfully produced.The types and contents of reinforcements strongly influence the properties of AM-produced MMCs,the choice of AM technology,and the applied processing parameters.In these MMCs,four primary strengthening mechanisms have been identified:Hall–Petch strengthening,dislocation strengthening,load transfer strengthening,and Orowan strengthening.AM technologies offer advantages that enhance the properties of MMCs when compared with traditional fabrication methods.Despite the advantages above,further challenges of AM-produced MMCs are still faced,such as new methods and new technologies for investigating AM-produced MMCs,the intrinsic nature of MMCs coupled with AM technologies,and challenges in the AM processes.Therefore,the article concludes by discussing the challenges and future interests of AM of MMCs.
基金National Key Research and Development Project of China(Grant No.2018YFA0901400)National Natural Science Foundation of China(Grant No.32070068).
文摘Metabolic engineering to produce tricarboxylic acid(TCA)cycle-derived chemicals is usually associated with problems of low production yield and impaired cellular metabolism.In this work,we found that fatty acid(FA)feedstocks could enable high-yield production of TCA cycle-derived chemicals,while maintaining an efficient and balanced metabolic flux of the glyoxylate-TCA cycle,which is favorable for both product synthesis and cell growth.Here,we designed a novel synthetic pathway for production of β-alanine,an important TCA cycle-derived product,from FAs with a high theortecial yield of 1.391 g/g.By introducing panD,improving aspA,and knocking out iclR,glyoxylate shunt was highly activated in FAs and the yield of β-alanine reached 0.71 g/g from FAs,much higher than from glucose.Blocking the TCA cycle at icd/sucA/fumAC nodes could increase β-alanine yield in a flask cultivation,but severely reduced cell growth and FA utilization during fed-batch processes.Replenishing oxaloacetate by knocking out aspC and recovering fumAC could restore the growth and lead to a titer of 35.57 g/l.After relieving the oxidative stress caused by FA metabolism,β-alanine production could reach 72.05 g/l with a maximum yield of 1.24 g/g,about 86% of the theoretical yield.Our study thus provides a promising strategy for the production of TCA cycle-derived chemicals.
基金supported by the Key Research and Development Program of Shaanxi Province(2019ZDLGY15-07)the Youth Innovation Team of Shaanxi Universities,and National Engineering Laboratory for Mobile Source Emission Control Technology(NELMS2017B02)。
文摘In the usage phase,diesel engines fuelled with diesel-biodiesel blends produced lower soot,HC and CO emissions.However,the environmental effects should include the greenhouse gas(GHG)emissions.GHG variations of biodiesel production from three generation feedstocks were analyzed based on the land use change(LUC).Adequate land use change could keep the biodiversity and did not cause the increase of GHG emissions.The choice for feedstocks of biodiesel in China was comprehensively analyzed based on the land use type,the precipitation and the oil contents and the cultivation conditions of plants.Then,the suggestions for biodiesel development in China were given.Results showed that China should thoroughly abandon the first generation feedstocks due to the lack of arable land.Jatropha curcas(J.curcas),Pistacia chinensis Bunge(P.chinensis),Comus wilsoniana(C.wilsoniana)and Xanthoceras sorbifolium Bunge(X.sorbifolium)were considered as the most promising feedstocks for biodiesel production.It is suggested to plant X.sorbifolium in sand lands in the north and northwest of China with less natural rainfall and the others in south and southwest of China.The concern for microalgae should be transmitted to engineering microalgae cultivated in wastewater.The microalgae biodiesel refinery should be developed together with wastewater proposal industry and coal fired power plants.Lastly,only natural gas-based or biomass-based methanol can be used for biodiesel production.
文摘Satellited CoNiCrAlY–Al_(2)O_(3)feedstocks with 2wt%, 4wt%, and 6wt% oxide nanoparticles and pure CoNiCrAlY powder were deposited by the high-velocity oxy fuel process on an Inconel738 superalloy substrate. The oxidation test was performed at 1050℃ for 5, 50, 100,150, 200, and 400 h. The microstructure and phase composition of powders and coatings were characterized by scanning electron microscopy and X-ray diffraction, respectively. The bonding strength of the coatings was also evaluated. The results proved that with the increase in the percentage of nanoparticles(from 2wt% to 6wt%), the amount of porosity(from 1vol% to 4.7vol%), unmelted particles, and roughness of the coatings(from 4.8 to 8.8 μm) increased, and the bonding strength decreased from 71 to 48 MPa. The thicknesses of the thermally grown oxide layer of pure and composite coatings(2wt%, 4wt%, and 6wt%) after 400 h oxidation were measured as 6.5, 5.5, 7.6, and 8.1 μm, respectively.The CoNiCrAlY–2wt% Al_(2)O_(3)coating showed the highest oxidation resistance due to the diffusion barrier effect of well-dispersed nanoparticles. The CoNiCrAlY–6wt% Al_(2)O_(3)coating had the lowest oxidation resistance due to its rough surface morphology and porous microstructure.
文摘The upgrading of diesel oil to produce ethylene rich cracking feedstock is an important and promising technical route to reduce the ratio of diesel to gasoline. In the present work, a hydrocracking catalyst suitable for selective hydrocracking of straight run diesel oil to produce high-quality ethylene cracking feedstock at low cost was developed, by optimizing the composition of catalyst support materials, using amorphous silicon aluminum and aluminum oxide with high mesopore content as the main support, and modified Y zeolite with excellent aromatic ring opening selectivity as the acidic component. The catalyst has in-depth characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N<sub>2</sub>-low temperature adsorption-desorption, NH<sub>3</sub>-temperature-programmed desorption, and IR techniques. And its catalytic cracking straight run diesel oil performance was evaluated. The results show that the prepared catalyst has high polycyclic aromatic hydrocarbon ring opening cracking selectivity. However, alkanes retained in diesel distillates can achieve the goal of producing more ethylene cracking feedstocks with low BMCI value under low and moderate pressure conditions. This work may shed significant technical insight for oil refining transformation.
文摘Ti-6Al-4V alloy powder was taken as raw material. 60%（mass fraction） paraffin, 35%low density polyethylene and 5%stearic acid were employed as binders to prepare injection feedstocks. Capillary rheometer was adopted to determine the rheological parameters and to analyze the rheological properties of the feedstocks at different milling time, powder loading and temperature. It is indicated through the results that the viscosity increases and the value of n decreases with the increase of milling time. The more the powder loading is, the higher the viscosity is. The empirical formula on the relationship between the viscosity and the powder loading is： ηr=η/ηb=A（1-Ф/Фmax）/^- m . The value m is calculated as 0.33. The flow activation energy Ea decreases with the increase of shear rate.
基金Financial support by the Spanish Government(RTI2018-099668-B-C21,PGC2018-097277-B-100,and SEV-2016-0683)the Severo Ochoa Excellence Program(SVP-2014-068669)the “La Caixa-Severo Ochoa” Foundation,respectively,for their fellowships~~
文摘This work reports the preparation of bulk and KIT-6-diluted W-Nb-O mixed oxide bronzes by a reflux method. The influence of the incorporation of Nb and a mesoporous silica on the physicochemical features of the catalysts is studied. The addition of Nb favors the formation of single-phase oxide bronze structure, with improved Lewis acidity;while the incorporation of KIT-6 gives rise to well-dispersed mixed metal oxide particles on the diluter. These diluted W-Nb-O catalysts present enhanced surface areas and mesopore volumes. The materials have been tested in the valorization of an aqueous model mixture (acetol/propanal/ethanol/acetic acid/water weight ratio of 5/25/10/30/30), through C-C bond formation reactions. The increase in the Lewis nature of surface acid sites stands as the key point to maximize the total organic yield during the reaction (C5-C10 products). The best catalysts maintain their catalytic behavior after five consecutive uses.
文摘3D Euler double-fluid model was applied and three different feedstocks and reverts formations were simulated. By calculating and analyzing the state of gas and solid fluxion in absorber using three different methods of the feedstocks and reverts in recirculating fluidized bed, described the behavior of gas and solid through the gas-phase velocity, turbulence intensity, gas-solid sliding velocity, and density of particles. The results show that the feedstocks and reverts enters into absorption tower through two symmetrical feedings and are mixed with flue gas. Based on the respective analysis of each model and the com- parison analysis of the three models, this paper drew conclusions. The turbulence intensity of absorption tower is high, gas-solid sliding speed is big, and granule concentration near the axis is high, which has advantages for desulfurization and im- proving the utilization rate of absorbent.
文摘This paper describes a brief review of biodiesel R & D developmental trends at Tarbiat Modares University (TMU) bio- energy research laboratories (lab.), Tehran, Iran. The developmental trends at includes potential and feasibility study, cultivation of a sample bioenrgy farm, technology innovation and its scale up (patents) for fuel processing, and finally the fuel application in diesel engines. A national investigation was carried out to find out the possible potential of sustainable feedstock for biodiesel production. The results showed that easily available biodiesel feedstock is waste cooking oil with a maximum potential of 750 mil.lit and an approximately 350 mil.lit. of collectable waste cooking oil. A castor oil plant farm was cultivated to harvest castor plant seeds, extract its oil, produce biodiesel fuel and use it in diesel engines. This led to a series of patent and consequently technology innovation from 7 lit. lab. scale to semi-continuous, semi-industrial scale of 2 ton capacity.
文摘A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well documented, but information is lacking for sweet sorghum. Three and six commercial cultivars of sugarcane and sweet sorghum, respectively, were selected and evaluated for exposure to a late fall frost (-2.8°C) in Griffin, Georgia, USA. Under the same controlled environmental conditions in a screen house, the late fall frost induced more damage to sugarcane than sweet sorghum stems. The frost caused damage to sugarcane tissue and for juice to exude from stems, whereas similar behavior was not observed for sweet sorghum. In both sugarcane and sweet sorghum, the glucose/fructose ratio was significantly reduced, but this change may not be totally directly related to the frost effect. Overall, these initial results suggest that sweet sorghum may have a better tolerance to fall frost than sugarcane. Two sweet sorghum cultivars, Grassl and M81E, responded well to the late fall frost, and they can possibly be used as feedstocks for biofuel/bioproduct manufacture in areas susceptible to frosts including northern regions of the Southeastern US.
基金Supported by Higher Education Commission(HEC)of Pakistan(No.21-1084).
文摘Biodiesel utilization has been rapidly growing worldwide as the prime alternative to petrodiesel due to a global rise in diesel fuel demand along with hazardous emissions during its thermochemical conversion.Although,several debatable issues including feedstock availability and price,fuel and food competition,changes in land use and greenhouse gas emission have been raised by using edible as well as inedible feedstocks for the production of biodiesel.However,non-crop feedstocks could be a promising alternative.In this article,waste cooking oils have been recommended as a suitable option for biodiesel production bearing in mind the current national situation.The important factors such as the quantity of waste cooking oil produced,crude oil and vegetable oil import expenses,high-speed diesel imports,waste management issues and environmental hazards are considered.Moreover,process simulation and operating cost evaluation of an acid catalyzed biodiesel production unit are also conducted.The simulation results show that the production cost of waste cooking oil-based biodiesel is about 0.66 USD·L-1.We believe that the present overview would open new pathways and ideas for the development of biofuels from waste to energy approach in Pakistan.
基金supported by the National Key Technology Research and Development Program of China(No.2006BAC02A03)the Key Project of Chinese Ministry of Education(No.107122)+1 种基金the 2006 Shanghai-Rhone Alpes Region(France)Scientific Research Cooperation Fund(No.06SR07105)the China Postdoctoral Science Foundation(No.20060390653).
文摘The vegetable wastes and flower stems were co-digested to evaluate the anaerobic hydrolysis performance of difficultly biodegradable organic wastes by introducing readily biodegradable organic wastes. The experiments were carried out in batches. When the vegetable wastes were mixed with the flower stems at the dry weight ratio of 1 to 13, the overall hydrolysis rate increased by 8%, 12%, and 2% according to the carbon, nitrogen, and total solid （TS） conversion rate, respectively. While the dry weight ratio was designed as 1 to 3, there was a respective rise of 5%, 15%, and 4% in the conversion rate of carbon, nitrogen, and TS. The enhancement of anaerobic hydrolysis from the mixed vegetable wastes and flower stems can be attributed to the formation of volatile fatty acids （VFA） and nutrient supplement like nitrogen content. The maximum VFA concentration can achieve 1.7 g/L owing to the rapid acidification of vegetable wastes, loosing the structure of lignocellulose materials. The statistic bivariate analysis revealed that the hydrolysis performance was significantly related to the physical and biochemical compositions of the feeding substrate. Especially, the soluble carbon concentration in the liquid was significantly positively correlated to the concentration of nitrogen and hemicellulose, and negatively correlated to the concentration of carbon and lignocellulose in the feeding substrate, suggesting that the regulation and control of feedstock can have an important influence on the anaerobic hydrolysis of organic wastes.
文摘Based on the analysis of flow characteristics of the FCC riser feedstock injection zone, two novel feedstock injection structures are put forward. By investigating three flow parameters in the feedstock injection zone under the three different structures (the traditional and the novel No. 1, No. 2 structures): the local density, the particle backmixng ratio, and the jet eigen-concentration, the flow feature under three structures were obtained. The experimental results demonstrate that the flow features under both proposed structures are obviously improved comparing with those under the traditional structure. Especially, the performance of the deflector-structured No. 2 is more desirable than that of No. 1.
基金supported by the National High-Tech Research and Development Program of China (No.2002AA331080)
文摘Nanocrystalline NiCrC alloy powders with a qualified particle size distribution for thermal spraying were synthesized using the cryogenic ball milling （cryomilling） method. The morphology, microstructure, size distribution, and phase transformation of the powders were characterized by scanning electron microscopy （SEM）, laser scattering for particle size analysis, X-ray diffraction （XRD）, and transmission electron microscopy （TEM）. After cryomilling for 20 h, the average grain size of the as-milled powders approached a constant value of 30 nm by XRD measurement. The average particle size slightly increased from 17.5 to 20.3 μm during the 20-h milling. About 90vol% of the powders satisfied the requirement for thermal spraying with the particle dimension of 10-50 μm, and most of the powders exhibited spherical morphology, which were expected to have good fluidity during thermal spraying. The Cr2O3 phase formed during the cryornilling process as revealed in the XRD spectra, which was expected to enhance the thermal stability of the as-milled powders during the followed thermal spraying or other heat treatment.
