Phototrophy and chemotrophy are two dominant types of microbial metabolism.However,to date,the potential of the ubiquitous and versatile mechanical energy as a renewable energy source to drive the growth of microorgan...Phototrophy and chemotrophy are two dominant types of microbial metabolism.However,to date,the potential of the ubiquitous and versatile mechanical energy as a renewable energy source to drive the growth of microorganisms has remained unknown and not utilized.Here,we present evidence in favor of a previously unidentified metabolic pathway,in which the electronic energy produced from mechanical energy by the piezoelectric materials is used to support the growth of microorganisms.When electroactive microorganism Rhodopseudomonas palustris(R.palustris;with barium titanate nanoparticles)was mechanically stirred,a powerful biohybrid piezoelectric effect(BPE)enabled sustainable carbon fixation coupled with nitrate reduction.Transcriptomic analyses demonstrated that mechanical stirring of the bacteria–barium titanate biohybrid led to upregulation of genes encoding functions involved in electron and energy transfer in R.palustris.Studies with other electroactive microorganisms suggested that the ability of microbes to utilize BPE may be a common phenomenon in the microbial world.Taken together,these findings imply a long-neglected and potentially important microbial metabolic pathway,with potential importance to microbial survival in the energy-limited environments.展开更多
To quantitatively address the role of tissue N in crop respiration under various agricultural practices, and to consequently evaluate the impact of synthetic fertilizer N application on biomass production and respirat...To quantitatively address the role of tissue N in crop respiration under various agricultural practices, and to consequently evaluate the impact of synthetic fertilizer N application on biomass production and respiration, and hence net carbon fixation efficiency （Encf）, pot and field experiments were carried out for an annual rotation of a rice-wheat cropping system from 2001 to 2003. The treatments of the pot experiments included fertilizer N application, sowing date and planting density. Different rates of N application were tested in the field experiments. Static opaque chambers were used for sampling the gas. The respiration as CO2 emission was detected by a gas chromatograph. A successive biomass clipping method was employed to determine the crop autotrophic respiration coefficient （Ra）. Results from the pot experiments revealed a linear relationship between Ra and tissue N content as Ra = 4.74N-1.45 （R^2= 0.85, P 〈 0.001）. Measurements and calculations from the field experiments indicated that fertilizer N application promoted not only biomass production but also increased the respiration of crops. A further investigation showed that the increase of carbon loss in terms of respiration owing to fertilizer N application exceeded that of net carbon gain in terms of aboveground biomass when fertilizer N was applied over a certain rate. Consequently, the Encf declined as the N application rate increased.展开更多
The Strait of Malacca （SoM）, the world＇s busiest sea-route, is increasingly polluted as the rapid develop- ment of world trades, affecting phytoplankton primary productivity therein. The variations of surface phy- ...The Strait of Malacca （SoM）, the world＇s busiest sea-route, is increasingly polluted as the rapid develop- ment of world trades, affecting phytoplankton primary productivity therein. The variations of surface phy- toplankton biomass, size-structure and carbon fixation were investigated across the SoM during the spring period （May 4 to 9, 2011）. Chlorophyll a concentration increased from 0.12 ptg/L at the northwest entrance of the SoM to a maximal 0.63 #g/L at narrowest section, and decreased to 0.10/.tg/L at the southeast entrance. Photosynthetic carbon fixation by phytoplankton coincided well with Chl a biomass, and increased from 10.8 to 22.3 pg C/（L.d）, then decreased to 9.21/zg C/（L.d）; while the carbon fixation rate showed an inverse pattern to the changes of Chl a, and decreased from 87.1 to 35.5 #g C/（#g Chl a.d） and increased thereafter to 95.3 btg C/（/2g Chl a.d）. Picophytoplankton cells （〈3/2m） contributed to more than 60% and 50% of the total Chl a and carbon fixation at both the entry waters; while the contributions of pico-cells decreased sharply to the minimum of 18.3% and 27.5% at the narrowest part of the SoM. In particular, our results showed that the silicate concentration positively regulated Chl a biomass and carbon fixation, reflecting that the higher silicate favoured the growth of phytoplankton and thus led to higher primary production in this strait.展开更多
To create evaluation methods in reclamation area according to specific conditions in coal mines, introduced the re- search trends both at home and abroad on plants＇ carbon fixation and oxygen release, offered, at the...To create evaluation methods in reclamation area according to specific conditions in coal mines, introduced the re- search trends both at home and abroad on plants＇ carbon fixation and oxygen release, offered, at the same time, several method models on carbon fixation and oxygen release by plants, and gave some suggestions in this field on the basis of reading the ex- periences of former experts. Finally, used biomass method and instrument measurement method to analyze carbon emission benefits in the study area.展开更多
[Objectives]To explore the effects of single application of chemical fertilizers on soil carbon fixation capacity and soil fertility under plastic film mulching conditions in eastern Qinghai,and to provide a theoretic...[Objectives]To explore the effects of single application of chemical fertilizers on soil carbon fixation capacity and soil fertility under plastic film mulching conditions in eastern Qinghai,and to provide a theoretical basis for realizing the sustainable development of film mulching planting method in this area.[Methods]The effects of single application of chemical fertilizer cultivation mode under film mulching conditions on the soil organic carbon(SOC),labile organic carbon(LOC),carbon management index(CMI),extractable humus carbon(CHE),humic acid carbon(CHA),and fulvic acid carbon(CFA)in the cultivated layer(0-20 cm)were studied through three consecutive years of field experiments on dryland maize farmland in the eastern Qinghai.[Results]Under the film mulching condition,the SOC,LOC and CMI of the single application of chemical fertilizer cultivation mode were lower than that of the open field control.CHE,CHA and CFA increased with the increase of planting years,but the degree of increase was generally less than that of the open field control.With the increase of planting years,by 2020,the soil LOC/SOC value of film mulching decreased by 4.97%compared with before the start of the experiment,while the open field control increased by 1.11%;the organic carbon oxidation stability coefficient(KOS)of the film mulching was higher than that of the open field control;the soil CHA/CFA value and PQ value were higher than that of the open field control.[Conclusions]Under the condition of single application of chemical fertilizers,the continuous film mulching cultivation mode reduces the soil carbon fixation capacity,and soil organic carbon tends to be stable,which is not conducive to biological utilization and could reduce the soil fertility and degrade the soil quality,causing adverse effects on the stability of crop yield and sustainable production in the long run.展开更多
In C_(3) plants,photorespiration is an energy expensive pathway that competes with photosynthetic CO_(2) assimilation and releases CO_(2) into the atmosphere,potentially reducing C_(3) plant productivity by 20%-50%.Co...In C_(3) plants,photorespiration is an energy expensive pathway that competes with photosynthetic CO_(2) assimilation and releases CO_(2) into the atmosphere,potentially reducing C_(3) plant productivity by 20%-50%.Consequently,reducing the flux through photorespiration has been recognized as a major way to improve C_(3) crop photosynthetic carbon fixation and productivity.While current research efforts in engineering photorespiration are mainly based on the modification of chloroplast glycolate metabolic steps,only limited studies have explored optimizations in other photorespiratory metabolic steps.Here,we engineered an imGS bypass within the rice mitochondria to bypass the photorespiratory glycine toward glycine betaine,thereby,improving the photosynthetic carbon fixation in rice.The imGS transgenic rice plants exhibited significant accumulation of glycine betaine,reduced photorespiration,and elevated photosynthesis and photosynthate levels.Additionally,the introduction of imGS bypass into rice leads to an increase in the number of branches and grains per panicle which may be related to cytokinin and gibberellin signaling pathways.Taken together,these results suggest diverting mitochondrial glycine from photorespiration toward glycine betaine synthesis can effectively enhance carbon fixation and panicle architecture in rice,offering a promising strategy for developing functional mitochondrial photorespiratory bypasses with the potential to enhance plant productivity.展开更多
Cadmium(Cd)contamination poses a significant threat to the carbon fixation potential of farmland ecosystems,yet the molecular mechanisms underlying its inhibitory effects remain poorly understood.This study reveals th...Cadmium(Cd)contamination poses a significant threat to the carbon fixation potential of farmland ecosystems,yet the molecular mechanisms underlying its inhibitory effects remain poorly understood.This study reveals that Cd competitively binds to ribulose-1,5-bisphosphate carboxylase/oxygenase(Rubisco),the key enzyme in photosynthetic carbon fixation,by displacing its native co-factor,magnesium(Mg).Both Cd^(2+)and Mg^(2+)bind to identical sites on Rubisco,forming a hexacoordinated complex with the oxygen atoms of ribulose-1,5-bisphosphate(RuBP)and key residues in Rubisco,including Asp203,His294,Glu204,and Lys201.While the binding affinity and stability of the Cd^(2+)-Rubisco-RuBP complex are comparable to those of the Mg^(2+)-Rubisco-RuBP complex,Cd^(2+)markedly shifts the catalytic activity of Rubisco from carboxylation to oxygenation.This shift results in the accumulation of 2-phosphoglycolate(2-PG),a photorespiration byproduct,by up to 11.57-fold.Consequently,the enhanced photorespiration pathway increases CO_(2) release,leading to a significant reduction in net CO_(2) fixation and ultimately inhibiting rice growth under hydroponic conditions.By elucidating the molecular mechanism through which Cd disrupts Rubisco’s dual catalytic activity,this study advances our understanding of how heavy metals impair carbon metabolism and carbon sequestration in plants,offering critical insights for mitigating Cd-induced carbon sink losses in cropland.展开更多
CO_(2)concentration mechanisms(CCMs)are important in maintaining the high efficiency of photosynthesis of marine algae.Aquatic photoautotrophs have two types of CCMs:biophysical CCMs,based on the conversion of inorgan...CO_(2)concentration mechanisms(CCMs)are important in maintaining the high efficiency of photosynthesis of marine algae.Aquatic photoautotrophs have two types of CCMs:biophysical CCMs,based on the conversion of inorganic carbon,and bio-chemical CCMs,based on the formation of C_(4)acid intermediates.However,the contribution of biophysical and biochemical CCMs to algal carbon fixation remains unclear.Here,we used ethoxyzolamide(EZ)inhibitors of carbonic anhydrase and 3-mercaptopicolinic acid(MPA)inhibitors for phosphoenolpyruvate carboxykinase to examine the importance of biophysi-cal and biochemical CCMs in photosynthesis of the green macroalga Ulva prolifera.The culture experiments showed that the carbon fixation of the species declined when EZ inhibited the biophysical CCM,while the increase in cyclic electron flow around the photosystem I indicated a more active biochemical CCM,contributing to~50%of total carbon fixation.The biophysical CCM was also reinforced when MPA inhibited the biochemical CCM.In a comparison,the biophysical CCM can compensate for almost 100%of total carbon fixation.The results indicate that biophysical CCMs dominate the process of carbon fixation of U.prolifera while biochemical CCM plays a supporting role.Our results provide evidence of a complementary coordination mechanism between the biophysical and biochemical CCMs that promotes the efficiency of photosynthesis of U.prolifera,an efficient mechanism to boost the alga’s bloom.展开更多
Global warming caused by the emission of CO_(2) in industrial flue gas has attractedmore and more attention.Therefore,to fix CO_(2) with high efficiency and environmentally friendly had become the hot research field.C...Global warming caused by the emission of CO_(2) in industrial flue gas has attractedmore and more attention.Therefore,to fix CO_(2) with high efficiency and environmentally friendly had become the hot research field.Compared with the traditional coal-fired power plant flue gas emission reduction technology,carbon fixation and emission reduction by microalgae is considered as a promising technology due to the advantages of simple process equipment,convenient operation and environmental protection.When the flue gas is treated by microalgae carbon fixation and emission reduction technology,microalgae cells can fix CO_(2) in the flue gas through photosynthesis,and simultaneously absorb NO_(x) and SO_(x) as nitrogen and sulfur sources required for growth.Meanwhile,they can also absorb mercury,selenium,arsenic,cadmium,lead and other heavy metal ions in the flue gas to obtain microalgae biomass.The obtained microalgae biomass can be further transformed into high valueadded products,which has broad development prospects.This paper reviews the mechanisms and pathways of CO_(2) sequestration,the mechanism and impacts of microalgal emission reduction of flue gas pollutants,and the applications of carbon sequestration in industrial flue gas by microalgae.Finally,this paper provides some guidelines and prospects for the research and application of green emission reduction technology for industrial flue gas.展开更多
Aerated drip irrigation(ADI)is an important practice for promoting soil fertility and crop productivity in greenhouse vegetable production,yet little research has comprehensively investigated its effects on the functi...Aerated drip irrigation(ADI)is an important practice for promoting soil fertility and crop productivity in greenhouse vegetable production,yet little research has comprehensively investigated its effects on the functional traits of carbon(C)-cycling microorganisms.In this study,we sought to assess the potential efficacy of ADI in increasing soil organic C(SOC)by changing soil microbial communities and the expressions of genes associated with C cycling.To this end,we adopted a metagenomic approach to compare the effects of ADI with three dissolved oxygen concentrations(10,15,and 20 mg L^(-1))during a three-season tomato cultivation experiment in northern China.The results revealed that the 10 mg L^(-1)treatment led to a significant increase in the abundance of korA/B genes(associated with the reductive tricarboxylic acid cycle)in the C fixation pathway,whereas the 15 mg L^(-1)treatment increased the abundances of cbbL/R and coxL/S genes associated with the Calvin cycle and carbon monoxide oxidation,respectively.In addition,based on a co-occurrence network analysis,we observed a positive correlation between cbbL and coxS.Interestingly,r-selected microorganisms,such as Proteobacteria and Actinobacteria,characterized by rapid cell multiplication and high biomass production,were identified as the primary contributors to C fixation and were the main predictors of SOC pools.In contrast,the 20 mg L^(-1)treatment was found to adversely influence C fixation,although the enhanced C degradation could be attributed to the extracellular enzymes secreted by K-selected microorganisms.Collectively,our findings indicate that ADI with dissolved oxygen concentrations 15 mg L^(-1)can promote SOC content by altering the life history strategies of r-selected microorganisms and genes associated with C fixation.These findings will provide valuable references for agroecosystem irrigation management,help improve soil fertility,and promote sustainable production.展开更多
Based on data from ChinaFLUX this study analyzed the daily value flow processes of carbon fixation, monthly value distribution, and daily accumulative processes in a year of two kinds of typical forest, two kinds of g...Based on data from ChinaFLUX this study analyzed the daily value flow processes of carbon fixation, monthly value distribution, and daily accumulative processes in a year of two kinds of typical forest, two kinds of grasses and a farmland. The results showed that the annual value of carbon fixation of these ecosystems was different, and flow processes and cumulative processes followed different trends over a year. The sequence of the five kinds of ecosystems based on the annual value of carbon fixation from largest to smallest was Yucheng warm temperate agriculture ecosystem （Yucheng）, Qianyanzhou subtropical artificial coniferous forest ecosystem （Qianyanzhou）, Changbai Mountain temperate mixed coniferous broad-leaved forest ecosystem （Changbaishan）, Haibei alpine meadow ecosystem （Haibei）and Dangxiong alpine meadow ecosystem （Dangxiong）. Variability in the daily and monthly carbon fixation at Qianyanzhou was the smallest, followed by Changbaishan, Yucheng, Dangxiong and Haibei. The cumulative processes of daily carbon fixation for the five kinds of ecosystems were well fitted to cubic curves.展开更多
Carbon fixation is the main route of inorganic carbon in the form of CO2 into the biosphere.In nature,RuBisCO is the most abundant protein that photosynthetic organisms use to fix CO2 from the atmosphere through the C...Carbon fixation is the main route of inorganic carbon in the form of CO2 into the biosphere.In nature,RuBisCO is the most abundant protein that photosynthetic organisms use to fix CO2 from the atmosphere through the Calvin-Benson-Bassham(CBB)cycle.However,the CBB cycle is limited by its low catalytic rate and low energy efficiency.In this work,we attempt to integrate the reductive tricarboxylic acid and CBB cycles in silico to further improve carbon fixation capacity.Key heterologous enzymes,mostly carboxylating enzymes,are inserted into the Esherichia coli core metabolic network to assimilate CO2 into biomass using hydrogen as energy source.Overall,such a strain shows enhanced growth yield with simultaneous running of dual carbon fixation cycles.Our key results include the following.(i)We identified two main growth states:carbon-limited and hydrogenlimited;(ii)we identified a hierarchy of carbon fixation usage when hydrogen supply is limited;and(iii)we identified the alternative sub-optimal growth mode while performing genetic perturbation.The results and modeling approach can guide bioengineering projects toward optimal production using such a strain as a microbial cell factory.展开更多
Paddy fields play an important role in global carbon(C) cycling and are an important source of methane(CH_(4)) emissions. Insights into the processes influencing the dynamics of soil organic C(SOC) in paddy fields are...Paddy fields play an important role in global carbon(C) cycling and are an important source of methane(CH_(4)) emissions. Insights into the processes influencing the dynamics of soil organic C(SOC) in paddy fields are essential for maintaining global soil C stocks and mitigating climate change. Periphytic biofilms composed of microalgae, bacteria, and other microorganisms are ubiquitous in paddy fields, where they directly mediate the transfer of elements at the soil-water interface. However, their contributions to C turnover and exchange have been largely neglected. Periphytic biofilms affect and participate in soil C dynamics by altering both abiotic(e.g., pH and redox potential) and biotic conditions(e.g., microbial community composition and metabolism). This review summarizes the contributions of periphytic biofilms to soil C cycling processes, including carbon dioxide fixation, SOC mineralization, and CH_(4) emissions. Future research should be focused on: i) the mechanisms underlying periphytic biofilm-induced C fixation and turnover and ii) quantifying the contributions of periphytic biofilms to soil C uptake, stabilization, and sequestration in paddy fields.展开更多
Copolymerization of carbon dioxide with epichlorohydrin was successfully carried out by usingNd(P_(204))_3-Al(i-Bu)_3 as catalyst (P_(204))=(RO)_2 POO--,R=CH_3 (CH_2),CH(C_2H_5) CH_2--). Addi-tion of carbonyl compound...Copolymerization of carbon dioxide with epichlorohydrin was successfully carried out by usingNd(P_(204))_3-Al(i-Bu)_3 as catalyst (P_(204))=(RO)_2 POO--,R=CH_3 (CH_2),CH(C_2H_5) CH_2--). Addi-tion of carbonyl compounds into the catalyst decreased the carbon dioxide content of the copoly-mer to some extent. Compared to nonpolar solvents, ethereal and moderate polar solvents werefavourable to obtaining higher carbon dioxide content copolymer. The coincidence of these resultswith the assumed copolymerization scheme clearly indicated that the copolymerization proceeds via coordinate anionic mechanism.展开更多
High atmospheric vapor pressure deficit(VPD)reduces the calcium(Ca)distribution in tomato(Solanum lycopersicum L.)fruits,severely reducing fruit mass.Reducing the VPD or increasing Ca fertilizer is an important measur...High atmospheric vapor pressure deficit(VPD)reduces the calcium(Ca)distribution in tomato(Solanum lycopersicum L.)fruits,severely reducing fruit mass.Reducing the VPD or increasing Ca fertilizer is an important measure to improve Ca distribution in fruits.However,the mechanism through which VPD and Ca regulate fruit Ca distribution remains unclear.This study investigated the effects of high and low VPD and Ca levels on Ca distribution and fruit mass based on carbon fixation,water transport dynamics,and pectin and Ca content and identified key differential genes and metabolites through transcriptome and metabolome analyses.The results showed that both reducing VPD under low Ca and increasing Ca under high VPD increased water and Ca transport to fruits.The increased Ca combined with pectin to form Ca pectinate,which effectively stabilized the cell wall and enhanced the fruit mass.Reduced VPD under low Ca increased the distribution of Ca to fruits but decreased the distribution of Ca to leaves.Lower Ca distribution in leaves increased their absorption of other nutrients,such as potassium,magnesium,copper,and zinc,which increased the stomatal size and density,thereby improving plant carbon absorption and assimilation efficiency.However,transcriptomic and metabolomic data indicated that carbohydrates,as important regulatory factors under drought stress,increased significantly under high VPD,thereby reducing the fruit water potential while improving fruit water and Ca absorption.Therefore,the carbon assimilation efficiency,water transport capacity,and differential genes and metabolites regulated Ca distribution.This work provides a theoretical basis for environmental and fertilizer management in greenhouse tomato production.展开更多
CO2 is not only the most important greenhouse gas but also an important resource of elemental carbon and oxygen.From the perspective of resource and energy strategy,the conversion of CO2 to chemicals driven by renewab...CO2 is not only the most important greenhouse gas but also an important resource of elemental carbon and oxygen.From the perspective of resource and energy strategy,the conversion of CO2 to chemicals driven by renewable energy is of significance,since it can not only reduce carbon emission by the utilization of CO2 as feedstock but also store low-grade renewable energy as high energy density chemical energy.Although studies on photoelectrocatalytic reduction of CO2 using renewable energy are increasing,artificial bioconversion of CO2 as an important novel pathway to synthesize chemicals has attracted more and more attention.By simulating the natural photosynthesis process of plants and microorganisms,the artificial bioconversion of CO2 can efficiently synthesize chemicals via a designed and constructed artificial photosynthesis system.This review focuses on the recent advancements in artificial bioreduction of CO2,including the key techniques,and artificial biosynthesis of compounds with different carbon numbers.On the basis of the aforementioned discussions,we present the prospects for further development of artificial bioconversion of CO2 to chemicals.展开更多
Crop carbon and water relations research is important in the studies of water saving agriculture, breeding program, and energy and material cycles in soil plant atmosphere continuum （SPAC）. The purpose of this paper...Crop carbon and water relations research is important in the studies of water saving agriculture, breeding program, and energy and material cycles in soil plant atmosphere continuum （SPAC）. The purpose of this paper is to review the current state of knowledge on stable isotopes of carbon, oxygen, and hydrogen in the research of crop carbon and water relations, such as carbon isotope discrimination （△^13C） during carbon fixation process by photosynthesis, application of △^13C in crop water use efficiency （WUE） and breeding programs, oxygen isotope enrichment during leaf water transpiration, CO2 fixation by photosynthesis and release by respiration, application of hydrogen isotope composition （619） and oxygen isotope composition （6180） for determination of water source used by a crop, stable isotope coupling Keeling plot for investigating the carbon and water flux in ecosystem, energy and material cycle in SPAC and correlative integrative models on stable isotope. These aspects contain most of the stable isotope researches on crop carbon and water relations which have been widely explored internationally while less referred in China. Based on the reviewed literatures, some needs for future research are suggested.展开更多
Some deep-sea microbes may incorporate inorganic carbon to reduce CO_(2) emission to upper layer and atmosphere.How the microbial inhabitants can be affected under addition of bicarbonate has not been studied using in...Some deep-sea microbes may incorporate inorganic carbon to reduce CO_(2) emission to upper layer and atmosphere.How the microbial inhabitants can be affected under addition of bicarbonate has not been studied using in situ fixed and lysed samples.In this study,we cultivated 40 L natural bottom water at~1000 m depth with a final concentration of 0.1 mmol/L bicarbonate for 40 min and applied multiple in situ nucleic acids collection(MISNAC)apparatus for nucleic acids extraction from the cultivation.Our classification result of the cultivation sample showed a distinct microbial community structure,compared with the samples obtained by Niskin bottle and six working units of MISNAC.Except for notable enrichment of Alteromonas,we detected prevalence of Asprobacter,Ilumatobacter and Saccharimonadales in the cultivation.Deep-sea lineages of Euryarchaeota,SAR406,SAR202 and SAR324 were almost completely absent from the cultivation and Niskin samples.This study revealed the dominant microbes affected by bicarbonate addition and Niskin sampling,which suggested rapid responses of deep-sea microbes to the environmental changes.展开更多
Taking a three-year fertilization trial in mine reclamation soil from Shanxi Province, China as an example, the effects of different fertilization treatments on soil carbon storage and carbon fixation by corn were stu...Taking a three-year fertilization trial in mine reclamation soil from Shanxi Province, China as an example, the effects of different fertilization treatments on soil carbon storage and carbon fixation by corn were studied in this paper. Four treatments were designed in the experiment, including fertilizer （ F）, organic manure （ M）, half organic manure plus half fertilizer （ FM） and control （CK）. The results showed that fertilization had certain roles in increasing organic carbon storage of mine reclamation soil, and the application of single or combined organic and inorganic fertilizers had the most remarkable influence. Meanwhile, the treatment of single or combined organic and inorganic fertilizers could improve the carbon fixation capacity of corn prominently, and increased soil organic matter input. Thus, the application of organic manure or combined organic and inorganic fertilizer has great contribution to enhancing soil carbon sink and sustainable development of agriculture. However, the combined application of organic and inorganic fertilizer is the best choice for agricultural field based on economic consideration.展开更多
Although microbial treatments of heavy metal ions in wastewater have been studied, the removal of these metals through incorporation into carbonate minerals has rarely been reported. To investigate the removal of Fe^3...Although microbial treatments of heavy metal ions in wastewater have been studied, the removal of these metals through incorporation into carbonate minerals has rarely been reported. To investigate the removal of Fe^3＋ and Pb^2＋, two representative metals in wastewater, through the precipitation of carbonate minerals by a microbial flocculant （MBF） produced by Bacillus mucilaginosus. MBF was added to synthetic wastewater containing different Fe^3＋ and Pb^2＋ concentrations, and the extent of flocculation was analyzed. CO2 was bubbled into the mixture of MBF and Fe^3＋/Pb^2＋ to initiate the reaction. The solid substrates were analyzed via X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy. The results showed that the removal efficiency decreased and the MBF adsorption capacity for metals increased with increasing heavy metal concentration. In the system containing MBF, metals （Fe^3＋ and Pb^2＋）, and CO2, the concentrated metals adsorbed onto the MBF combined with the dissolved CO2, resulting in oversaturation of metal carbonate minerals to form iron carbonate and lead carbonates. These results may be used in designing a method in which microbes can be utilized to combine CO2 with wastewater heavy metals to form carbonates, with the aim of mitigating environmental problems.展开更多
基金supported by the National Science Fund for Distinguished Young Scholars grant(41925028)the National Natural Science Foundation of China grant(42322706,42307176,and 42177206)。
文摘Phototrophy and chemotrophy are two dominant types of microbial metabolism.However,to date,the potential of the ubiquitous and versatile mechanical energy as a renewable energy source to drive the growth of microorganisms has remained unknown and not utilized.Here,we present evidence in favor of a previously unidentified metabolic pathway,in which the electronic energy produced from mechanical energy by the piezoelectric materials is used to support the growth of microorganisms.When electroactive microorganism Rhodopseudomonas palustris(R.palustris;with barium titanate nanoparticles)was mechanically stirred,a powerful biohybrid piezoelectric effect(BPE)enabled sustainable carbon fixation coupled with nitrate reduction.Transcriptomic analyses demonstrated that mechanical stirring of the bacteria–barium titanate biohybrid led to upregulation of genes encoding functions involved in electron and energy transfer in R.palustris.Studies with other electroactive microorganisms suggested that the ability of microbes to utilize BPE may be a common phenomenon in the microbial world.Taken together,these findings imply a long-neglected and potentially important microbial metabolic pathway,with potential importance to microbial survival in the energy-limited environments.
文摘To quantitatively address the role of tissue N in crop respiration under various agricultural practices, and to consequently evaluate the impact of synthetic fertilizer N application on biomass production and respiration, and hence net carbon fixation efficiency （Encf）, pot and field experiments were carried out for an annual rotation of a rice-wheat cropping system from 2001 to 2003. The treatments of the pot experiments included fertilizer N application, sowing date and planting density. Different rates of N application were tested in the field experiments. Static opaque chambers were used for sampling the gas. The respiration as CO2 emission was detected by a gas chromatograph. A successive biomass clipping method was employed to determine the crop autotrophic respiration coefficient （Ra）. Results from the pot experiments revealed a linear relationship between Ra and tissue N content as Ra = 4.74N-1.45 （R^2= 0.85, P 〈 0.001）. Measurements and calculations from the field experiments indicated that fertilizer N application promoted not only biomass production but also increased the respiration of crops. A further investigation showed that the increase of carbon loss in terms of respiration owing to fertilizer N application exceeded that of net carbon gain in terms of aboveground biomass when fertilizer N was applied over a certain rate. Consequently, the Encf declined as the N application rate increased.
基金The National Natural Science Foundation of China under contract Nos 41130855,41206132 and 41276162the Natural Science Foundation of Guangdong under contract No.S2011040000151+2 种基金CAS Knowledge Innovation Program under contract No.SQ201115National Project of Sciences and Technology under contract No.2008FY110100CAS Strategic Pilot Science and Technology under contract No.XDA05030403
文摘The Strait of Malacca （SoM）, the world＇s busiest sea-route, is increasingly polluted as the rapid develop- ment of world trades, affecting phytoplankton primary productivity therein. The variations of surface phy- toplankton biomass, size-structure and carbon fixation were investigated across the SoM during the spring period （May 4 to 9, 2011）. Chlorophyll a concentration increased from 0.12 ptg/L at the northwest entrance of the SoM to a maximal 0.63 #g/L at narrowest section, and decreased to 0.10/.tg/L at the southeast entrance. Photosynthetic carbon fixation by phytoplankton coincided well with Chl a biomass, and increased from 10.8 to 22.3 pg C/（L.d）, then decreased to 9.21/zg C/（L.d）; while the carbon fixation rate showed an inverse pattern to the changes of Chl a, and decreased from 87.1 to 35.5 #g C/（#g Chl a.d） and increased thereafter to 95.3 btg C/（/2g Chl a.d）. Picophytoplankton cells （〈3/2m） contributed to more than 60% and 50% of the total Chl a and carbon fixation at both the entry waters; while the contributions of pico-cells decreased sharply to the minimum of 18.3% and 27.5% at the narrowest part of the SoM. In particular, our results showed that the silicate concentration positively regulated Chl a biomass and carbon fixation, reflecting that the higher silicate favoured the growth of phytoplankton and thus led to higher primary production in this strait.
文摘To create evaluation methods in reclamation area according to specific conditions in coal mines, introduced the re- search trends both at home and abroad on plants＇ carbon fixation and oxygen release, offered, at the same time, several method models on carbon fixation and oxygen release by plants, and gave some suggestions in this field on the basis of reading the ex- periences of former experts. Finally, used biomass method and instrument measurement method to analyze carbon emission benefits in the study area.
基金Project of Natural Science Foundation of Qinghai Province(2018-ZJ-724)Major Science and Technology Program of Qinghai Province(2019-NK-A11).
文摘[Objectives]To explore the effects of single application of chemical fertilizers on soil carbon fixation capacity and soil fertility under plastic film mulching conditions in eastern Qinghai,and to provide a theoretical basis for realizing the sustainable development of film mulching planting method in this area.[Methods]The effects of single application of chemical fertilizer cultivation mode under film mulching conditions on the soil organic carbon(SOC),labile organic carbon(LOC),carbon management index(CMI),extractable humus carbon(CHE),humic acid carbon(CHA),and fulvic acid carbon(CFA)in the cultivated layer(0-20 cm)were studied through three consecutive years of field experiments on dryland maize farmland in the eastern Qinghai.[Results]Under the film mulching condition,the SOC,LOC and CMI of the single application of chemical fertilizer cultivation mode were lower than that of the open field control.CHE,CHA and CFA increased with the increase of planting years,but the degree of increase was generally less than that of the open field control.With the increase of planting years,by 2020,the soil LOC/SOC value of film mulching decreased by 4.97%compared with before the start of the experiment,while the open field control increased by 1.11%;the organic carbon oxidation stability coefficient(KOS)of the film mulching was higher than that of the open field control;the soil CHA/CFA value and PQ value were higher than that of the open field control.[Conclusions]Under the condition of single application of chemical fertilizers,the continuous film mulching cultivation mode reduces the soil carbon fixation capacity,and soil organic carbon tends to be stable,which is not conducive to biological utilization and could reduce the soil fertility and degrade the soil quality,causing adverse effects on the stability of crop yield and sustainable production in the long run.
基金Biological Breeding-National Science and Technology Major Project(2023ZD04072)the National Natural Science Foundation of China(32070265).
文摘In C_(3) plants,photorespiration is an energy expensive pathway that competes with photosynthetic CO_(2) assimilation and releases CO_(2) into the atmosphere,potentially reducing C_(3) plant productivity by 20%-50%.Consequently,reducing the flux through photorespiration has been recognized as a major way to improve C_(3) crop photosynthetic carbon fixation and productivity.While current research efforts in engineering photorespiration are mainly based on the modification of chloroplast glycolate metabolic steps,only limited studies have explored optimizations in other photorespiratory metabolic steps.Here,we engineered an imGS bypass within the rice mitochondria to bypass the photorespiratory glycine toward glycine betaine,thereby,improving the photosynthetic carbon fixation in rice.The imGS transgenic rice plants exhibited significant accumulation of glycine betaine,reduced photorespiration,and elevated photosynthesis and photosynthate levels.Additionally,the introduction of imGS bypass into rice leads to an increase in the number of branches and grains per panicle which may be related to cytokinin and gibberellin signaling pathways.Taken together,these results suggest diverting mitochondrial glycine from photorespiration toward glycine betaine synthesis can effectively enhance carbon fixation and panicle architecture in rice,offering a promising strategy for developing functional mitochondrial photorespiratory bypasses with the potential to enhance plant productivity.
基金supported by the National Natural Science Foundation of China(Nos.22436006 and 22306158).
文摘Cadmium(Cd)contamination poses a significant threat to the carbon fixation potential of farmland ecosystems,yet the molecular mechanisms underlying its inhibitory effects remain poorly understood.This study reveals that Cd competitively binds to ribulose-1,5-bisphosphate carboxylase/oxygenase(Rubisco),the key enzyme in photosynthetic carbon fixation,by displacing its native co-factor,magnesium(Mg).Both Cd^(2+)and Mg^(2+)bind to identical sites on Rubisco,forming a hexacoordinated complex with the oxygen atoms of ribulose-1,5-bisphosphate(RuBP)and key residues in Rubisco,including Asp203,His294,Glu204,and Lys201.While the binding affinity and stability of the Cd^(2+)-Rubisco-RuBP complex are comparable to those of the Mg^(2+)-Rubisco-RuBP complex,Cd^(2+)markedly shifts the catalytic activity of Rubisco from carboxylation to oxygenation.This shift results in the accumulation of 2-phosphoglycolate(2-PG),a photorespiration byproduct,by up to 11.57-fold.Consequently,the enhanced photorespiration pathway increases CO_(2) release,leading to a significant reduction in net CO_(2) fixation and ultimately inhibiting rice growth under hydroponic conditions.By elucidating the molecular mechanism through which Cd disrupts Rubisco’s dual catalytic activity,this study advances our understanding of how heavy metals impair carbon metabolism and carbon sequestration in plants,offering critical insights for mitigating Cd-induced carbon sink losses in cropland.
基金supported by Program of Shanghai Academic/Technology Research Leader[grant number 23XD1401200]the Natural Science Foundation of Fujian Province of China[grant number 2022J01026]+2 种基金the Natural Science Foundation of Shandong Province of China[grant number ZR2019ZD17]Binzhou Medical University Visiting Fellowship Programand the MEL Young Scientist Visiting Fellowship Program[grant number MELRS2103].
文摘CO_(2)concentration mechanisms(CCMs)are important in maintaining the high efficiency of photosynthesis of marine algae.Aquatic photoautotrophs have two types of CCMs:biophysical CCMs,based on the conversion of inorganic carbon,and bio-chemical CCMs,based on the formation of C_(4)acid intermediates.However,the contribution of biophysical and biochemical CCMs to algal carbon fixation remains unclear.Here,we used ethoxyzolamide(EZ)inhibitors of carbonic anhydrase and 3-mercaptopicolinic acid(MPA)inhibitors for phosphoenolpyruvate carboxykinase to examine the importance of biophysi-cal and biochemical CCMs in photosynthesis of the green macroalga Ulva prolifera.The culture experiments showed that the carbon fixation of the species declined when EZ inhibited the biophysical CCM,while the increase in cyclic electron flow around the photosystem I indicated a more active biochemical CCM,contributing to~50%of total carbon fixation.The biophysical CCM was also reinforced when MPA inhibited the biochemical CCM.In a comparison,the biophysical CCM can compensate for almost 100%of total carbon fixation.The results indicate that biophysical CCMs dominate the process of carbon fixation of U.prolifera while biochemical CCM plays a supporting role.Our results provide evidence of a complementary coordination mechanism between the biophysical and biochemical CCMs that promotes the efficiency of photosynthesis of U.prolifera,an efficient mechanism to boost the alga’s bloom.
基金supported by the National Key R&D Program of China(No.2023YFC3709500).
文摘Global warming caused by the emission of CO_(2) in industrial flue gas has attractedmore and more attention.Therefore,to fix CO_(2) with high efficiency and environmentally friendly had become the hot research field.Compared with the traditional coal-fired power plant flue gas emission reduction technology,carbon fixation and emission reduction by microalgae is considered as a promising technology due to the advantages of simple process equipment,convenient operation and environmental protection.When the flue gas is treated by microalgae carbon fixation and emission reduction technology,microalgae cells can fix CO_(2) in the flue gas through photosynthesis,and simultaneously absorb NO_(x) and SO_(x) as nitrogen and sulfur sources required for growth.Meanwhile,they can also absorb mercury,selenium,arsenic,cadmium,lead and other heavy metal ions in the flue gas to obtain microalgae biomass.The obtained microalgae biomass can be further transformed into high valueadded products,which has broad development prospects.This paper reviews the mechanisms and pathways of CO_(2) sequestration,the mechanism and impacts of microalgal emission reduction of flue gas pollutants,and the applications of carbon sequestration in industrial flue gas by microalgae.Finally,this paper provides some guidelines and prospects for the research and application of green emission reduction technology for industrial flue gas.
基金financially supported by the National Natural Science Foundation of China(Nos.52379048 and 52079112)the Key Research and Development Program of Shaanxi Province,China(No.2022ZDLNY03-03)the Major Science and Technology Engineering Innovation Project of Shandong Province,China(No.2020CXGC 010808)。
文摘Aerated drip irrigation(ADI)is an important practice for promoting soil fertility and crop productivity in greenhouse vegetable production,yet little research has comprehensively investigated its effects on the functional traits of carbon(C)-cycling microorganisms.In this study,we sought to assess the potential efficacy of ADI in increasing soil organic C(SOC)by changing soil microbial communities and the expressions of genes associated with C cycling.To this end,we adopted a metagenomic approach to compare the effects of ADI with three dissolved oxygen concentrations(10,15,and 20 mg L^(-1))during a three-season tomato cultivation experiment in northern China.The results revealed that the 10 mg L^(-1)treatment led to a significant increase in the abundance of korA/B genes(associated with the reductive tricarboxylic acid cycle)in the C fixation pathway,whereas the 15 mg L^(-1)treatment increased the abundances of cbbL/R and coxL/S genes associated with the Calvin cycle and carbon monoxide oxidation,respectively.In addition,based on a co-occurrence network analysis,we observed a positive correlation between cbbL and coxS.Interestingly,r-selected microorganisms,such as Proteobacteria and Actinobacteria,characterized by rapid cell multiplication and high biomass production,were identified as the primary contributors to C fixation and were the main predictors of SOC pools.In contrast,the 20 mg L^(-1)treatment was found to adversely influence C fixation,although the enhanced C degradation could be attributed to the extracellular enzymes secreted by K-selected microorganisms.Collectively,our findings indicate that ADI with dissolved oxygen concentrations 15 mg L^(-1)can promote SOC content by altering the life history strategies of r-selected microorganisms and genes associated with C fixation.These findings will provide valuable references for agroecosystem irrigation management,help improve soil fertility,and promote sustainable production.
基金National Natural Science Foundation of China (31070384)
文摘Based on data from ChinaFLUX this study analyzed the daily value flow processes of carbon fixation, monthly value distribution, and daily accumulative processes in a year of two kinds of typical forest, two kinds of grasses and a farmland. The results showed that the annual value of carbon fixation of these ecosystems was different, and flow processes and cumulative processes followed different trends over a year. The sequence of the five kinds of ecosystems based on the annual value of carbon fixation from largest to smallest was Yucheng warm temperate agriculture ecosystem （Yucheng）, Qianyanzhou subtropical artificial coniferous forest ecosystem （Qianyanzhou）, Changbai Mountain temperate mixed coniferous broad-leaved forest ecosystem （Changbaishan）, Haibei alpine meadow ecosystem （Haibei）and Dangxiong alpine meadow ecosystem （Dangxiong）. Variability in the daily and monthly carbon fixation at Qianyanzhou was the smallest, followed by Changbaishan, Yucheng, Dangxiong and Haibei. The cumulative processes of daily carbon fixation for the five kinds of ecosystems were well fitted to cubic curves.
基金Y.T.Y.would like to acknowledge funding support from the Ministry of Science and Technology under grant numbers MOST 105-2221-E-007-130-MY3 and MOST 107-2621-M-007-001-MY3C.C.H.would like to acknowledge funding support from the Ministry of Science and Technology under grant numbers MOST 107-2621-M-005-007-MY3 and 107-2621-M-005-001.
文摘Carbon fixation is the main route of inorganic carbon in the form of CO2 into the biosphere.In nature,RuBisCO is the most abundant protein that photosynthetic organisms use to fix CO2 from the atmosphere through the Calvin-Benson-Bassham(CBB)cycle.However,the CBB cycle is limited by its low catalytic rate and low energy efficiency.In this work,we attempt to integrate the reductive tricarboxylic acid and CBB cycles in silico to further improve carbon fixation capacity.Key heterologous enzymes,mostly carboxylating enzymes,are inserted into the Esherichia coli core metabolic network to assimilate CO2 into biomass using hydrogen as energy source.Overall,such a strain shows enhanced growth yield with simultaneous running of dual carbon fixation cycles.Our key results include the following.(i)We identified two main growth states:carbon-limited and hydrogenlimited;(ii)we identified a hierarchy of carbon fixation usage when hydrogen supply is limited;and(iii)we identified the alternative sub-optimal growth mode while performing genetic perturbation.The results and modeling approach can guide bioengineering projects toward optimal production using such a strain as a microbial cell factory.
基金financial support from the National Natural Science Foundation of China(Nos.41825021 and 42207447)the National Key Research and Development Program of China(No.2021YFD17008)+3 种基金the Provincial Natural Science Foundation of Jiangsu,China(No.BK20220004)the Postdoctoral Science Foundation of China(Nos.BX2021325 and 2022M723242)the State Key Laboratory of Lake Science and Environment Foundation,China(No.2022SKL008)EJ was supported by the TüBITAK program BIDEB2232 of Türkiye(No.118C250)。
文摘Paddy fields play an important role in global carbon(C) cycling and are an important source of methane(CH_(4)) emissions. Insights into the processes influencing the dynamics of soil organic C(SOC) in paddy fields are essential for maintaining global soil C stocks and mitigating climate change. Periphytic biofilms composed of microalgae, bacteria, and other microorganisms are ubiquitous in paddy fields, where they directly mediate the transfer of elements at the soil-water interface. However, their contributions to C turnover and exchange have been largely neglected. Periphytic biofilms affect and participate in soil C dynamics by altering both abiotic(e.g., pH and redox potential) and biotic conditions(e.g., microbial community composition and metabolism). This review summarizes the contributions of periphytic biofilms to soil C cycling processes, including carbon dioxide fixation, SOC mineralization, and CH_(4) emissions. Future research should be focused on: i) the mechanisms underlying periphytic biofilm-induced C fixation and turnover and ii) quantifying the contributions of periphytic biofilms to soil C uptake, stabilization, and sequestration in paddy fields.
文摘Copolymerization of carbon dioxide with epichlorohydrin was successfully carried out by usingNd(P_(204))_3-Al(i-Bu)_3 as catalyst (P_(204))=(RO)_2 POO--,R=CH_3 (CH_2),CH(C_2H_5) CH_2--). Addi-tion of carbonyl compounds into the catalyst decreased the carbon dioxide content of the copoly-mer to some extent. Compared to nonpolar solvents, ethereal and moderate polar solvents werefavourable to obtaining higher carbon dioxide content copolymer. The coincidence of these resultswith the assumed copolymerization scheme clearly indicated that the copolymerization proceeds via coordinate anionic mechanism.
基金supported by grants from the Construction of Shaanxi Vegetable Industry Technology System in 2022[Grant No.NYKJ-2022-(XN)-03]the Construction of the Scientists+Engineers Team in Qin Chuangyuan,Shaanxi Province(Grant No.2023KXJ-024)。
文摘High atmospheric vapor pressure deficit(VPD)reduces the calcium(Ca)distribution in tomato(Solanum lycopersicum L.)fruits,severely reducing fruit mass.Reducing the VPD or increasing Ca fertilizer is an important measure to improve Ca distribution in fruits.However,the mechanism through which VPD and Ca regulate fruit Ca distribution remains unclear.This study investigated the effects of high and low VPD and Ca levels on Ca distribution and fruit mass based on carbon fixation,water transport dynamics,and pectin and Ca content and identified key differential genes and metabolites through transcriptome and metabolome analyses.The results showed that both reducing VPD under low Ca and increasing Ca under high VPD increased water and Ca transport to fruits.The increased Ca combined with pectin to form Ca pectinate,which effectively stabilized the cell wall and enhanced the fruit mass.Reduced VPD under low Ca increased the distribution of Ca to fruits but decreased the distribution of Ca to leaves.Lower Ca distribution in leaves increased their absorption of other nutrients,such as potassium,magnesium,copper,and zinc,which increased the stomatal size and density,thereby improving plant carbon absorption and assimilation efficiency.However,transcriptomic and metabolomic data indicated that carbohydrates,as important regulatory factors under drought stress,increased significantly under high VPD,thereby reducing the fruit water potential while improving fruit water and Ca absorption.Therefore,the carbon assimilation efficiency,water transport capacity,and differential genes and metabolites regulated Ca distribution.This work provides a theoretical basis for environmental and fertilizer management in greenhouse tomato production.
基金supported by the National Natural Science Foundation of China (91745114, 21802160)the National Key R&D Program of China (2016YFA0202800)+2 种基金Shanghai Sailing Program (18YF1425700)Shanghai Advanced Research Institute Innovation Research Program (Y756812ZZ1(172002),Y756803ZZ1(171003))the support from the Hundred Talents Program of the Chinese Academy of Sciences~~
文摘CO2 is not only the most important greenhouse gas but also an important resource of elemental carbon and oxygen.From the perspective of resource and energy strategy,the conversion of CO2 to chemicals driven by renewable energy is of significance,since it can not only reduce carbon emission by the utilization of CO2 as feedstock but also store low-grade renewable energy as high energy density chemical energy.Although studies on photoelectrocatalytic reduction of CO2 using renewable energy are increasing,artificial bioconversion of CO2 as an important novel pathway to synthesize chemicals has attracted more and more attention.By simulating the natural photosynthesis process of plants and microorganisms,the artificial bioconversion of CO2 can efficiently synthesize chemicals via a designed and constructed artificial photosynthesis system.This review focuses on the recent advancements in artificial bioreduction of CO2,including the key techniques,and artificial biosynthesis of compounds with different carbon numbers.On the basis of the aforementioned discussions,we present the prospects for further development of artificial bioconversion of CO2 to chemicals.
基金supported by the National Basic Re-search Program of China (973 Program) (2005CB121103)the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-406KSCX1-YW-09-05)
文摘Crop carbon and water relations research is important in the studies of water saving agriculture, breeding program, and energy and material cycles in soil plant atmosphere continuum （SPAC）. The purpose of this paper is to review the current state of knowledge on stable isotopes of carbon, oxygen, and hydrogen in the research of crop carbon and water relations, such as carbon isotope discrimination （△^13C） during carbon fixation process by photosynthesis, application of △^13C in crop water use efficiency （WUE） and breeding programs, oxygen isotope enrichment during leaf water transpiration, CO2 fixation by photosynthesis and release by respiration, application of hydrogen isotope composition （619） and oxygen isotope composition （6180） for determination of water source used by a crop, stable isotope coupling Keeling plot for investigating the carbon and water flux in ecosystem, energy and material cycle in SPAC and correlative integrative models on stable isotope. These aspects contain most of the stable isotope researches on crop carbon and water relations which have been widely explored internationally while less referred in China. Based on the reviewed literatures, some needs for future research are suggested.
基金The Hainan Provincial Natural Science Foundation of China under contract No.322CXTD531the National Key Research and Development Program of China under contract Nos 2018YFC0310005,2016YFC0302504.
文摘Some deep-sea microbes may incorporate inorganic carbon to reduce CO_(2) emission to upper layer and atmosphere.How the microbial inhabitants can be affected under addition of bicarbonate has not been studied using in situ fixed and lysed samples.In this study,we cultivated 40 L natural bottom water at~1000 m depth with a final concentration of 0.1 mmol/L bicarbonate for 40 min and applied multiple in situ nucleic acids collection(MISNAC)apparatus for nucleic acids extraction from the cultivation.Our classification result of the cultivation sample showed a distinct microbial community structure,compared with the samples obtained by Niskin bottle and six working units of MISNAC.Except for notable enrichment of Alteromonas,we detected prevalence of Asprobacter,Ilumatobacter and Saccharimonadales in the cultivation.Deep-sea lineages of Euryarchaeota,SAR406,SAR202 and SAR324 were almost completely absent from the cultivation and Niskin samples.This study revealed the dominant microbes affected by bicarbonate addition and Niskin sampling,which suggested rapid responses of deep-sea microbes to the environmental changes.
基金Supported by the International Science and Technology Cooperation Program of China(2011DFR31230)Major Science and Technology Project of Shanxi Province,China(20121101009)Key Project of Shanxi Academy of Agricultural Sciences,China(2013zd12)
文摘Taking a three-year fertilization trial in mine reclamation soil from Shanxi Province, China as an example, the effects of different fertilization treatments on soil carbon storage and carbon fixation by corn were studied in this paper. Four treatments were designed in the experiment, including fertilizer （ F）, organic manure （ M）, half organic manure plus half fertilizer （ FM） and control （CK）. The results showed that fertilization had certain roles in increasing organic carbon storage of mine reclamation soil, and the application of single or combined organic and inorganic fertilizers had the most remarkable influence. Meanwhile, the treatment of single or combined organic and inorganic fertilizers could improve the carbon fixation capacity of corn prominently, and increased soil organic matter input. Thus, the application of organic manure or combined organic and inorganic fertilizer has great contribution to enhancing soil carbon sink and sustainable development of agriculture. However, the combined application of organic and inorganic fertilizer is the best choice for agricultural field based on economic consideration.
基金supported by the National Science Foundation for Creative Research Groups(No.41021062)the National Key Basic Research Program of China(No.2013CB956700)
文摘Although microbial treatments of heavy metal ions in wastewater have been studied, the removal of these metals through incorporation into carbonate minerals has rarely been reported. To investigate the removal of Fe^3＋ and Pb^2＋, two representative metals in wastewater, through the precipitation of carbonate minerals by a microbial flocculant （MBF） produced by Bacillus mucilaginosus. MBF was added to synthetic wastewater containing different Fe^3＋ and Pb^2＋ concentrations, and the extent of flocculation was analyzed. CO2 was bubbled into the mixture of MBF and Fe^3＋/Pb^2＋ to initiate the reaction. The solid substrates were analyzed via X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy. The results showed that the removal efficiency decreased and the MBF adsorption capacity for metals increased with increasing heavy metal concentration. In the system containing MBF, metals （Fe^3＋ and Pb^2＋）, and CO2, the concentrated metals adsorbed onto the MBF combined with the dissolved CO2, resulting in oversaturation of metal carbonate minerals to form iron carbonate and lead carbonates. These results may be used in designing a method in which microbes can be utilized to combine CO2 with wastewater heavy metals to form carbonates, with the aim of mitigating environmental problems.
