Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation(MICP)process.For MICP-based insitu biotreatment...Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation(MICP)process.For MICP-based insitu biotreatment,the firstproblem to be solved is how to introduce and retain the bacterial cells in the soil,which involves the migration and retention of bacterial cells during the biogrouting process.Soil particle size,a key factor in determining pore throat size,can have a significanteffect on the migration and retention of bacterial cells in the soil and therefore on biomineralization.To investigate the effect of particle size on the migration and retention of bacterial cells in sand and its biomineralization,two sets of tests were carried out in this study,including percolation tests and sand column treatment tests.Soil urease activity(definedas urease activity per unit mass of soil)and calcium carbonate content of the biomineralized sand were measured to comprehensively assess the migration and retention of bacterial cells in the sand.The results indicate that sands with a particle size smaller than 0.25 mmwould inhibit the migration of bacteria in the sand,resulting in a nonuniform distribution of precipitated calcium carbonate and a low strength enhancement of biomineralization.On the other hand,sands with a particle size larger than 1.18 mm are unfavorable for retaining bacterial cells in the sand,resulting in low calcium conversion efficiency.Meanwhile,particle size would also affect the formation of effective calcium carbonate through interparticle contact number and interparticle pore size,and thus biomineralization.展开更多
Biomineralization based on bacterial enzyme induced carbonate precipitation(BEICP)process is a promising alternative to cement-based ground treatment technology.The bacterial urease used in BEICP process is usually ul...Biomineralization based on bacterial enzyme induced carbonate precipitation(BEICP)process is a promising alternative to cement-based ground treatment technology.The bacterial urease used in BEICP process is usually ultrasonic extracted from urease-producing bacteria.To efficiently extract urease with relatively higher activity from bacterial cells,the ultrasonic extraction parameters of urease were optimized in this study.Next,a series of bacterial urease extraction tests and sand column treatment tests were conducted to investigate the effects of vibration amplitude,upper temperature limit,and cooling method on the urease extraction process and biomineralization of sand.The results show that the upper temperature limit is an important factor affecting the extraction efficiency and the activity of the extracted urease solution,and the optimum upper temperature limit is 50℃.The results indicate that increasing vibration amplitude could improve the extraction efficiency,but it hardly affects the urease activity(UA)under the optimal temperature.Continuous cooling could effectively simplify the operation and further improve the efficiency of urease extraction.Under the same urease activity of biotreatment solution,there is no marked difference in calcium carbonate content(CCC)and unconfined compressive strength of biomineralized sand columns prepared by urease solution extracted with different vibration amplitudes and upper temperature limits.The results of this study could provide a reference for application of BEICP technology of urease extraction to large-scale soil treatment.展开更多
Tumor blockade therapy inhibits tumor progression by cutting off essential supplies of nutrients,oxygen,and biomolecules from the surrounding microenvironments.Inspired by natural processes,tumor biomineralization has...Tumor blockade therapy inhibits tumor progression by cutting off essential supplies of nutrients,oxygen,and biomolecules from the surrounding microenvironments.Inspired by natural processes,tumor biomineralization has evolved due to its biocompatibility,self-reinforcing capability,and penetrationindependent mechanism.However,the selective induction of tumor biomineralization using synthetic tools presents a significant challenge.Herein,a metabolic glycoengineering-assistant tumor biomineralization strategy was developed.Specifically,the azido group(N_(3))was introduced onto the cytomembrane by incubating tumor cells with glycose analog Ac4ManNAz.In addition,a bisphosphonate-containing polymer,dibenzocyclooctyne-poly(ethylene glycol)-alendronate(DBCO-PEG-ALN,DBPA)was synthesized,which attached to the tumor cell surface via"click chemistry"reaction between DBCO and N_(3).Subsequently,the bisphosphonate group on the cell surface chelated with positively charged ions in the microenvironments,triggering a consecutive process of biomineralization.This physical barrier significantly reduced tumor cell viability and mobility in a calcium ion concentration-dependent manner,suggesting its potential as an effective anti-tumor strategy for in vivo applications.展开更多
A simulated experimental reduction of and the synthesis of uraninite by a sulfate-reducing bacteria, Desulfovibrio desulfuricans DSM 642, are first reported. The simulated physicochemical experimental conditions were:...A simulated experimental reduction of and the synthesis of uraninite by a sulfate-reducing bacteria, Desulfovibrio desulfuricans DSM 642, are first reported. The simulated physicochemical experimental conditions were: 35°C, pH=7.0-7.4, corresponding to the environments of formation of the sandstone-hosted interlayer oxidation-zone type uranium deposits in Xinjiang, NW China. Uraninite was formed on the surface of the host bacteria after a one-week's incubation. Therefore, sulfate-reducing bacteria, which existed extensively in Jurassic sandstone-producing environments, might have participated in the biomineralization of this uranium deposit. There is an important difference in the order- disorder of the crystalline structure between the uraninite produced by Desulfovibrio desulfuricans and naturally occurring uraninite. Long time and slow precipitation and growth of uraninite in the geological environment might have resulted in larger uraninite crystals, with uraninite nanocrystals arranged in order, whereas the experimentally produced uraninite is composed of unordered uraninite nanocrystals which, in contrast, result from the short time span of formation and rapid precipitation and growth of uraninite. The discovery has important implications for understanding genetic significance in mineralogy, and also indicates that in-situ bioremediation of U-contaminated environments and use of biotechnology in the treatment of radioactive liquid waste is being contemplated.展开更多
Biological dissimilatory reduction of selenite （SeO3^2-） to elemental selenium （Se^0） is common, but the mineral formation and the biogenic process remain uncertain. In this study, we examined the Se^0 formation d...Biological dissimilatory reduction of selenite （SeO3^2-） to elemental selenium （Se^0） is common, but the mineral formation and the biogenic process remain uncertain. In this study, we examined the Se^0 formation during the selenite bioreduction by Bacillus licheniformis SeRB-1 through transmission electron microscope （TEM）, energy-dispersive spectrometry （EDS） and X-ray absorption fine structure （XAFS） techniques. Results showed that the reduction process occurred mostly during the exponential phase and early stationary phase, whilst the elemental selenium was produced in these periods. From the TEM images and polyaerylamide gel eleetropheresis, it is known that the Se^0 granule formation is a biologically-induced type, and the cell envelopes are the main biomineralization positions, and particles may go through a process from nucleation to crystallization, under the control of microbes. In fact, the minerals are spherical nanoparticles, occurring as a microcrystal or amorphous form. It is vital to recognize which kinds of proteins and/or polysaccharides act as a template to direct nanoparticle nucleation and growth？ This should focus for further studies. This study may shed light on the process of formation of Se（0） nanosphere.展开更多
Microbiologically influenced corrosion(MIC)of steel generates a corrosion product film,which can also be called biomineralization film.It is critical to understand the structure of biomineralization film since it domi...Microbiologically influenced corrosion(MIC)of steel generates a corrosion product film,which can also be called biomineralization film.It is critical to understand the structure of biomineralization film since it dominates the corrosion behavior of metal.In this work,Pseudomonas stutzeri(P.stutzeri)was isolated from seawater,and the biomineralization film caused by marine P.stutzeri was characterized by Transmission electron microscopy(TEM),scanning electron microscopy(SEM),X-ray diffraction(XRD),etc.The mechanistic effects of the biomineralization film on X80 pipeline steel corrosion were also investigated.The results indicate that the minerals are mainly composed of nano FeOand FeOOH,according to TEM and XRD results.The particle sizes of biominerals are below 10 nm.This work also provides an insight strategy to prepare nanomaterials by MIC caused by P.stutzeri.In addition,P.stutzeri can grow well with COas a carbon source and iron as an electron donor.The corrosion rates(CRs)of specimens are closely related to the structure of biomineralization film.The CRs increase with the decrease of initial cell concentration.P.stutzeri with an initial concentration of 10~7 cells/mL can promote the formation of a compact biomineralization film with a thickness of 145.8±4.8μm,leading to corrosion inhibition with a CR of 0.058±0.008 mm/y.But some corrosion pits can be observed due to the formation of small anodes.Electrochemical impedance spectroscopy(EIS)data show higher impedance values and two time-constants,which imply the formation of a compact biomineralization film.展开更多
The mechanical and physical properties of biodegradable magnesium(Mg)alloys make them suitable for temporary orthopaedic implants.The success of these alloys depends on their performance in the physiological environme...The mechanical and physical properties of biodegradable magnesium(Mg)alloys make them suitable for temporary orthopaedic implants.The success of these alloys depends on their performance in the physiological environment.In the present work,surface modification of Mg-Ca binary alloy by acid pickling for better biomineralization and controlled biodegradation is explored.The corrosion rates of nitric and phosphoric acid treated samples were analysed by conducting electrochemical corrosion tests.In vitro degradation behaviour was studied using immersion test in simulated body fluid(SBF).The sample surfaces were characterized using scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS).It is seen that acid pickling leads to significant improvement in biomineralization and develop in situ calcium phosphate(Ca P)coating on the sample surfaces.In addition,the treated samples recorded a reduced degradation rate in the SBF compared to untreated samples.Thus,acid pickling is suggested as an effective surface treatment method to tailor the biomineralization and degradation behaviour of the Mg-Ca alloy in the physiological environment.展开更多
Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chl...Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this paper.Two series of biomineralization tests in solution and sand column,respectively,were conducted.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) crystals.The experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this study.The difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).展开更多
Magnetotactic bacteria can orientate in the Earth’s magnetic field to search for their preferred microoxic environments,which is achieved by their unique organelles,the magnetosomes.Magnetosomes contain nanometer-siz...Magnetotactic bacteria can orientate in the Earth’s magnetic field to search for their preferred microoxic environments,which is achieved by their unique organelles,the magnetosomes.Magnetosomes contain nanometer-sized crystal particles of magnetic iron minerals,which are only synthesized in lowoxygen environments.Although the mechanism of aerobic repression for magnetosome biomineralization has not yet fully understood,a series of studies have verified that redox modulation is pivotal for magnetosome formation.In this review,these advances in redox modulation for magnetosome biosynthesis are highlighted,mainly including respiration pathway enzymes,specific magnetosome-associated redox proteins,and oxygen-or nitrate-sensing regulators.Furthermore,their relationship during magnetosome biomineralization is discussed to give insight into redox control and biomineralization and inspire potential solutions for the application of respiration pathways to improve the yields of magnetosome.展开更多
Growing evidence suggests that the presence of cancer stem cells(CSCs)is a major challenge in current tumor treatments,especially the transition from non-CSCs to differentiation of CSCs for evading conventional therap...Growing evidence suggests that the presence of cancer stem cells(CSCs)is a major challenge in current tumor treatments,especially the transition from non-CSCs to differentiation of CSCs for evading conventional therapies and driving metastasis.Here we propose a therapeutic strategy of synergistic differentiation therapy and phototherapy to induce differentiation of CSCs into mature tumor cells by differentiation inducers and synergistic elimination of them and normal cancer cells through phototherapy.In this work,we synthesized a biomimetic nanoplatform loaded with IR-780 and all-trans retinoic acid(ATRA)via biomineralization.This method can integrate aluminum ions into small-sized protein carriers to form nanoclusters,which undergo responsive degradation under acidic conditions and facilitate deep tumor penetration.With the help of CSC differentiation induced by ATRA,IR-780 inhibited the self-renewal of CSCs and cancer progression by generating hyperthermia and reactive oxygen species in a synergistic manner.Furthermore,ATRA can boost immunogenic cell death induced by phototherapy,thereby strongly causing a systemic anti-tumor immune response and efficiently eliminating CSCs and tumor cells.Taken together,this dual strategy represents a new paradigm of targeted eradication of CSCs and tumors by inducing CSC differentiation,improving photothermal therapy/photodynamic therapy and enhancing antitumor immunity.展开更多
Pyritic stromatolite, a rich pyrite ore, is scattered as reef masses in sedex deposits of the Proterozoic Yanshan rift trough. The pyritic stromatolite consists of a core and alternating concentric rims of light collo...Pyritic stromatolite, a rich pyrite ore, is scattered as reef masses in sedex deposits of the Proterozoic Yanshan rift trough. The pyritic stromatolite consists of a core and alternating concentric rims of light colloidal pyrite and dark organic materials. The concentric rims are cemented together by trichomes highly similar to the trichomic microorganisms inhabiting substantively around the black chimneys on the current sea beds while the core is composed chiefly of groups of thermophilous sulphur bacteria. Biomarkers for the molecules of pyritic stromatolite include pristane, phytane, regular isoprenoids paraffin, methyl-heptadecyl, and so on. This study reveals the existence of methane-yielding bacteria in the pyritic stromatolite and reflects the evolution of thermophilous thallophyta.展开更多
As a biosorbent,algae are frequently used for the biotreatment or bioremediation of water contaminated by heavymetal or radionuclides.However,it is unclear that whether or not the biomineralization of these metal or r...As a biosorbent,algae are frequently used for the biotreatment or bioremediation of water contaminated by heavymetal or radionuclides.However,it is unclear that whether or not the biomineralization of these metal or radionuclides can be induced by algae in the process of bioremediation and what the mechanism is.In this work,Ankistrodsemus sp.has been used to treat the uranium-contaminated water,and more than 98%of uranium in the solution can be removed by the alga,when the initial uranium concentration ranges from 10 to 80 mg/L.Especially,an unusual phenomenon of algae-induced uranium biomineralization has been found in the process of uranium bioremediation and its mineralization mechanism has been explored bymultiple approaches.It is worth noticing that the biomineralization of uranium induced by Ankistrodsemus sp.is significantly affected by contact time and pH.Uranium is captured rapidly on the cell surface via complexation with the carboxylate radical,amino and amide groups of themicroalgae cells,which provides nucleation sites for the precipitation of insolubleminerals.Uranium stimulates Ankistrodsemus sp.to metabolize potassium ions(K+),which may endow algae with the ability to biomineralize uranium into the rose-like compreignacite(K_(2)[(UO_(2))6O_(4)(OH)_(6)]•8H_(2)O).As the time increased,the amorphous gradually converted into compreignacite crystals and a large number of crystals would expand over both inside and outside the cells.To the best of our knowledge,this is the first investigated microalgae with a time-dependent uranium biomineralization ability and superior tolerance to uranium.This work validates that Ankistrodsemus sp.is a promising alga for the treatment of uranium-contaminated wastewater.展开更多
Bone and teeth are derived from intrafibrillarly mineralized collagen fibrils as the second level of hierarchy.According to polymer-induced liquid-precursor process,using amorphous calcium phosphate precursor(ACP)is a...Bone and teeth are derived from intrafibrillarly mineralized collagen fibrils as the second level of hierarchy.According to polymer-induced liquid-precursor process,using amorphous calcium phosphate precursor(ACP)is able to achieve intrafibrillar mineralization in the case of bone biomineral in vitro.Therefore,ACP precursors might be blended with any osteoconductive scaffold as a promising bone formation supplement for in-situ remineralization of collagens in bone.In this study,mesoporous silica nanoparticles with carboxyl-functionalized groups and ultra large-pores have been synthesized and used for the delivery of liquid like biomimetic precursors(ACP).The precursor delivery capacity of the nanoparticles was verified by the precursor release profile and successful mineralization of 2D and 3D collagen models.The nanoparticles could be completely degraded in 60 days and exhibited good biocompatibility as well.The successful translational strategy for biomineralization precursors showed that biomineralization precursor laden ultra large pore mesoporous silica possessed the potential as a versatile supplement in demineralized bone formation through the induction of intrafibrillar collagen mineralization.展开更多
K16 and RGD-containing peptide was used to modify the surface of three-dimensional PLGA-（ASP-PEG） matrix, then the modified PLGA-（ASP-PEG） was incubated in modified simulated body fluid （SBF）. The biomineralizat...K16 and RGD-containing peptide was used to modify the surface of three-dimensional PLGA-（ASP-PEG） matrix, then the modified PLGA-（ASP-PEG） was incubated in modified simulated body fluid （SBF）. The biomineralization of the modified PLGA- （ASP-PEG） was explored, and the peptide was synthesized with solid phase synthesis technology and linked cova-lently to PLGA-（ASP-PEG） through cross-linker （Sulfo-LC-SPDP）, which was characterized with XPS. The modified PLGA-（ASP-PEG） （Experiment group, EG） and PLGA-（ASP-PEG） （Control group, CG） were all incubated into SBF for 10 d, and the growth of hydroxyapatite （HA） nanocrys-tals was confirmed with XRD, EDS and SEM. HPLC shows that peptide purity is 94.13%, while MS analysis shows that molecular value of peptide is 2741.26. Binding energy of the sulphur in EG was 164 eV is detected by XPS, and the ratio of carbon and sulphur is 99.746：0.1014. SEM analysis demonstrates the better growth of bonelike HA nanocrystals in EG than that in CG. The component of mineral in EG consisted mainly of hydroxyapatite containing low crystalline nanocrystals, and the Ca/P ratio is about 1.60, which is similar to that of natural bone, while the Ca/P ratio in CG is 1.52. PLGA-（ASP-PEG） modified with peptide provided enough functional groups for biomineralization, and possessed the bonelike structure.展开更多
Geological and geochemical studies and experiments on mineralization indicate that the source bed of the La' erma gold deposit in the south subbelt of the western Qinling Mountains is hydrothermal cherts in the Ca...Geological and geochemical studies and experiments on mineralization indicate that the source bed of the La' erma gold deposit in the south subbelt of the western Qinling Mountains is hydrothermal cherts in the Cambrian Taiyangding Group. Organic geochemical study of the cherts shows that the organic precursors intimately associated with gold are marine bacteria and algae. The gold content in chert,is positively correlated with the amount of bacterial and algal microfossils, and simulation experiments on biomineralization of modern bacteria and algae indicate that bacteria and algae played an important role in the formation of the La' erma gold deposit.展开更多
The one-phase-low-pH method is a simple,efficient,and user-friendly biogrouting technique that can effectively improve the biomineralization of enzyme-induced carbonate precipitation(EICP)using free urease enzyme.One ...The one-phase-low-pH method is a simple,efficient,and user-friendly biogrouting technique that can effectively improve the biomineralization of enzyme-induced carbonate precipitation(EICP)using free urease enzyme.One of the most significant advantages of this method is its capacity to effectively delay calcium carbonate(CaCO3)precipitation by reducing the pH of the solution through the addition of acid.This prevents bioclogging during the biogrouting process and improves the biomineralization effect.However,the biomineralization of the one-phase-low-pH based EICP method may be influenced by the specific acid used.To investigate the impact of acid type on the one-phase-low-pH EICP method using crude soybean urease solution(CSUS),four types of acids,including hydrochloric acid(HCl),nitric acid(HNO_(3)),acetic acid(CH_(3)COOH),and lactic acid(C_(3)H_(6)O_(3)),were used to adjust the pH of CSUS.A series of macroscopic and microscopic experiments were conducted to evaluate the effect of acid type on the onephase-low-pH EICP method.The results indicate that the acid has an inhibition on the urease activity(UA)of CSUS.Among the acids tested,HNO_(3)exhibits the most pronounced inhibitory effect on the UA of CSUS,followed by HCl,and the least pronounced inhibitory effect for CH_(3)COOH and C3H6O_(3)under the same pH conditions.Meanwhile,CH_(3)COOH and C_(3)H_(6)O_(3)could provide a longer delay duration of CaCO_(3)precipitation than HNO_(3)and HCl.Therefore,the one-phase-low-pH EICP method based on CH_(3)COOH and C_(3)H_(6)O_(3)can significantly improve the effective biocementation depth compared to that based on HNO_(3)and HCl.Nevertheless,the different types of acids appear to have no obvious effect on the polymorph and crystalline of the precipitated CaCO_(3)crystals.展开更多
The origin of ancient banded iron formation （BIF） has remained unclear for a long time. How the precipitation process occurred and what the environmental condition was have been widely discussed among scientists, be...The origin of ancient banded iron formation （BIF） has remained unclear for a long time. How the precipitation process occurred and what the environmental condition was have been widely discussed among scientists, because the period when the major BIFs deposited （-2.8 to 1.8Ga） is the same time when biosphere and atmosphere significantly changed. Based on the discovery of modern seafloor hydrothermal vents, it is possible that reductive environment controlled by vent system is related to the environment where BIF was deposited. According to matter source.展开更多
Up to now, chemical synthesis routes only provide restricted opportunities for the formation of structured nano particles. In contrast, living microorganisms generate nano materials of well defined shapes by the preci...Up to now, chemical synthesis routes only provide restricted opportunities for the formation of structured nano particles. In contrast, living microorganisms generate nano materials of well defined shapes by the precise control of biomineralization. Here we reveal new principles for the generation of functional nano materials through the process of biomineralization. We used the detoxification mechanism of the unicellular alga Scenedesmus obliquus to generate a techno logically interesting zinc-phosphate-based nano material. The algae were incubated in media with a sublethal zinc concentration (6.53 mg Zn dm-3) for 4 weeks. Using BF-and ADF-STEM imaging combined with analytical XEDS we could show that nano needles containing phosphorus and zinc were formed inside the living cells. Further more, the cells incubated with zinc show a strong fluorescence. Our findings indicate that the algae used polyphosphate bodies for detoxification of the zinc ions, leading to the generation of intracellular zinc-phosphate-based nano needles. Beside the technological application of this material, the fluorescent cells can be used for labeling of e.g. biological probes. This new experimental protocol for the production of an inorganic functional material can be applied also for other substances.展开更多
Heavy metal contamination of soil and water is one of the most prominent environmental issues worldwide.Through bioaccumulation and biomagnification of the food chain,heavy metals can be enriched hundreds of times and...Heavy metal contamination of soil and water is one of the most prominent environmental issues worldwide.Through bioaccumulation and biomagnification of the food chain,heavy metals can be enriched hundreds of times and eventually enter the human body,posing a major threat to human health.Biomineralization has the greatest potential to become an efficient and environmentally friendly heavy metal remediation technology and has received much attention in recent decades.This review summarizes the latest progress of biomineralization technology on carbonate precipitation and phosphate precipitation in heavy metal remediation.Both microorganisms(including bacteria and fungi)and enzymes can induce carbonate and phosphate precipitation,converting the free heavy metal ions into insoluble salts.However,the mechanisms of the heavy metal remediation are significantly different.For example,urea hydrolysis,which occurs intracellularly when urease-producing bacteria(UPB)are used,is the most commonly used mechanism for carbonate precipitation based bioremediation.In contrast,phosphate solubilization by either enzymes or organic acids secreted by phosphate solubilizing bacteria(PSB)is extracellular,and both soluble and insoluble phosphorus can be decomposed by PSB.Moreover,some influencing factors such as the different species of microorganism,heavy metals and some environmental conditions that may affect the bioremediation of heavy metals were also summarized in this paper.The challenges of biomineralization based heavy metal remediation are also discussed.Based on the reviews of previous studies,a comprehensive understanding of heavy metal removal through microorganism can be increased,and thus promotes the applications of biomineralization technology in the treatment of large-scale heavy metal contaminated sites.展开更多
In this review paper,the applications of biomineralization in environmental geotechnics are analyzed.Three environmental geotechnics scenarios,namely heavy metal contamination immobilization and removal,waste and CO_(...In this review paper,the applications of biomineralization in environmental geotechnics are analyzed.Three environmental geotechnics scenarios,namely heavy metal contamination immobilization and removal,waste and CO_(2)containment,and recycled use of industrial byproducts,are discussed and evaluated regarding current trends and prospects.The biomineralization process,specifically the Microbially Induced Carbonate Precipitation(MICP)technology,is an effective solution for immobilizing heavy metals through co-precipitation with calcium carbonate,with successful results in cleaning up contaminated soils.The nature of biomineralization enhances earth material strength and decreases permeability,making it suitable for waste and CO_(2)containment.Additionally,using industrial byproducts in MICP technology can improve the physical,mechanical,and hydraulic properties of earth materials,making it a potential solution for efficient waste utilization.In conclusion,the applications of biomineralization in environmental geotechnics hold great promise for solving various environmental problems.However,further research is needed to better understand the control and consistency of biomineralization processes,the durability of biominerals,the scale of applications,and environmental concerns.展开更多
基金support by the National Natural Science Foundation of China(NSFC)(Grant Nos.52178319,42477160,52338007).
文摘Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation(MICP)process.For MICP-based insitu biotreatment,the firstproblem to be solved is how to introduce and retain the bacterial cells in the soil,which involves the migration and retention of bacterial cells during the biogrouting process.Soil particle size,a key factor in determining pore throat size,can have a significanteffect on the migration and retention of bacterial cells in the soil and therefore on biomineralization.To investigate the effect of particle size on the migration and retention of bacterial cells in sand and its biomineralization,two sets of tests were carried out in this study,including percolation tests and sand column treatment tests.Soil urease activity(definedas urease activity per unit mass of soil)and calcium carbonate content of the biomineralized sand were measured to comprehensively assess the migration and retention of bacterial cells in the sand.The results indicate that sands with a particle size smaller than 0.25 mmwould inhibit the migration of bacteria in the sand,resulting in a nonuniform distribution of precipitated calcium carbonate and a low strength enhancement of biomineralization.On the other hand,sands with a particle size larger than 1.18 mm are unfavorable for retaining bacterial cells in the sand,resulting in low calcium conversion efficiency.Meanwhile,particle size would also affect the formation of effective calcium carbonate through interparticle contact number and interparticle pore size,and thus biomineralization.
基金the National Natural Science Foundation of China(NSFC)(Grant Nos.52108307 and 52178319)the Natural Science Foundation of Fujian Province,China(Grant No.2022J05020).
文摘Biomineralization based on bacterial enzyme induced carbonate precipitation(BEICP)process is a promising alternative to cement-based ground treatment technology.The bacterial urease used in BEICP process is usually ultrasonic extracted from urease-producing bacteria.To efficiently extract urease with relatively higher activity from bacterial cells,the ultrasonic extraction parameters of urease were optimized in this study.Next,a series of bacterial urease extraction tests and sand column treatment tests were conducted to investigate the effects of vibration amplitude,upper temperature limit,and cooling method on the urease extraction process and biomineralization of sand.The results show that the upper temperature limit is an important factor affecting the extraction efficiency and the activity of the extracted urease solution,and the optimum upper temperature limit is 50℃.The results indicate that increasing vibration amplitude could improve the extraction efficiency,but it hardly affects the urease activity(UA)under the optimal temperature.Continuous cooling could effectively simplify the operation and further improve the efficiency of urease extraction.Under the same urease activity of biotreatment solution,there is no marked difference in calcium carbonate content(CCC)and unconfined compressive strength of biomineralized sand columns prepared by urease solution extracted with different vibration amplitudes and upper temperature limits.The results of this study could provide a reference for application of BEICP technology of urease extraction to large-scale soil treatment.
基金supported by the National Natural Science Foundation of China(Nos.U23A20591 and 52273158)the Science and Technology Development Program of Jilin Province(Nos.20240101002JJ and 20210504001GH).
文摘Tumor blockade therapy inhibits tumor progression by cutting off essential supplies of nutrients,oxygen,and biomolecules from the surrounding microenvironments.Inspired by natural processes,tumor biomineralization has evolved due to its biocompatibility,self-reinforcing capability,and penetrationindependent mechanism.However,the selective induction of tumor biomineralization using synthetic tools presents a significant challenge.Herein,a metabolic glycoengineering-assistant tumor biomineralization strategy was developed.Specifically,the azido group(N_(3))was introduced onto the cytomembrane by incubating tumor cells with glycose analog Ac4ManNAz.In addition,a bisphosphonate-containing polymer,dibenzocyclooctyne-poly(ethylene glycol)-alendronate(DBCO-PEG-ALN,DBPA)was synthesized,which attached to the tumor cell surface via"click chemistry"reaction between DBCO and N_(3).Subsequently,the bisphosphonate group on the cell surface chelated with positively charged ions in the microenvironments,triggering a consecutive process of biomineralization.This physical barrier significantly reduced tumor cell viability and mobility in a calcium ion concentration-dependent manner,suggesting its potential as an effective anti-tumor strategy for in vivo applications.
基金the National Science Foundation.USA.(NSF Grant EAR 02-10820)the National Natural ScienceFoundation of China(NSFC Grant No.40173031)+1 种基金the International Cooperative Research Foundation of NSFC(Grant No.2002-40210104086) the Ph.D.Base Foundation of the Ministry of Education of China(Grant No.20020284036).
文摘A simulated experimental reduction of and the synthesis of uraninite by a sulfate-reducing bacteria, Desulfovibrio desulfuricans DSM 642, are first reported. The simulated physicochemical experimental conditions were: 35°C, pH=7.0-7.4, corresponding to the environments of formation of the sandstone-hosted interlayer oxidation-zone type uranium deposits in Xinjiang, NW China. Uraninite was formed on the surface of the host bacteria after a one-week's incubation. Therefore, sulfate-reducing bacteria, which existed extensively in Jurassic sandstone-producing environments, might have participated in the biomineralization of this uranium deposit. There is an important difference in the order- disorder of the crystalline structure between the uraninite produced by Desulfovibrio desulfuricans and naturally occurring uraninite. Long time and slow precipitation and growth of uraninite in the geological environment might have resulted in larger uraninite crystals, with uraninite nanocrystals arranged in order, whereas the experimentally produced uraninite is composed of unordered uraninite nanocrystals which, in contrast, result from the short time span of formation and rapid precipitation and growth of uraninite. The discovery has important implications for understanding genetic significance in mineralogy, and also indicates that in-situ bioremediation of U-contaminated environments and use of biotechnology in the treatment of radioactive liquid waste is being contemplated.
基金financially supported by the National Natural Science Foundation of China (No. 41273029)National Basic Research Program of China (No. 2014CB238903)
文摘Biological dissimilatory reduction of selenite （SeO3^2-） to elemental selenium （Se^0） is common, but the mineral formation and the biogenic process remain uncertain. In this study, we examined the Se^0 formation during the selenite bioreduction by Bacillus licheniformis SeRB-1 through transmission electron microscope （TEM）, energy-dispersive spectrometry （EDS） and X-ray absorption fine structure （XAFS） techniques. Results showed that the reduction process occurred mostly during the exponential phase and early stationary phase, whilst the elemental selenium was produced in these periods. From the TEM images and polyaerylamide gel eleetropheresis, it is known that the Se^0 granule formation is a biologically-induced type, and the cell envelopes are the main biomineralization positions, and particles may go through a process from nucleation to crystallization, under the control of microbes. In fact, the minerals are spherical nanoparticles, occurring as a microcrystal or amorphous form. It is vital to recognize which kinds of proteins and/or polysaccharides act as a template to direct nanoparticle nucleation and growth？ This should focus for further studies. This study may shed light on the process of formation of Se（0） nanosphere.
基金supported by the National Natural Science Foundation of China(No.51901253)Fundamental Research Funds for the Central Universities(No.19lgzd18)+2 种基金Guangdong Basic and Applied Basic Research Foundation(No.2019A1515011135)the Open Project Program of Beijing Key Laboratory of Pipeline Critical Technology and Equipment for Deepwater Oil&Gas Development(No.BIPT201904)the Open Project Program of Hubei Key Laboratory of Materials Chemistry and Service Failure(No.2020MCF02)。
文摘Microbiologically influenced corrosion(MIC)of steel generates a corrosion product film,which can also be called biomineralization film.It is critical to understand the structure of biomineralization film since it dominates the corrosion behavior of metal.In this work,Pseudomonas stutzeri(P.stutzeri)was isolated from seawater,and the biomineralization film caused by marine P.stutzeri was characterized by Transmission electron microscopy(TEM),scanning electron microscopy(SEM),X-ray diffraction(XRD),etc.The mechanistic effects of the biomineralization film on X80 pipeline steel corrosion were also investigated.The results indicate that the minerals are mainly composed of nano FeOand FeOOH,according to TEM and XRD results.The particle sizes of biominerals are below 10 nm.This work also provides an insight strategy to prepare nanomaterials by MIC caused by P.stutzeri.In addition,P.stutzeri can grow well with COas a carbon source and iron as an electron donor.The corrosion rates(CRs)of specimens are closely related to the structure of biomineralization film.The CRs increase with the decrease of initial cell concentration.P.stutzeri with an initial concentration of 10~7 cells/mL can promote the formation of a compact biomineralization film with a thickness of 145.8±4.8μm,leading to corrosion inhibition with a CR of 0.058±0.008 mm/y.But some corrosion pits can be observed due to the formation of small anodes.Electrochemical impedance spectroscopy(EIS)data show higher impedance values and two time-constants,which imply the formation of a compact biomineralization film.
基金financial grant No.5/4–5/3ORTHO/2019-NCD-I Dt.16–09–2019 from Indian Council of Medical Research(ICMR)the grant from DST-FIST-No.SR/FST/ETI-388/2015,Govt.of India used for setting up 3D Profilometer facility at NIT Calicut。
文摘The mechanical and physical properties of biodegradable magnesium(Mg)alloys make them suitable for temporary orthopaedic implants.The success of these alloys depends on their performance in the physiological environment.In the present work,surface modification of Mg-Ca binary alloy by acid pickling for better biomineralization and controlled biodegradation is explored.The corrosion rates of nitric and phosphoric acid treated samples were analysed by conducting electrochemical corrosion tests.In vitro degradation behaviour was studied using immersion test in simulated body fluid(SBF).The sample surfaces were characterized using scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS).It is seen that acid pickling leads to significant improvement in biomineralization and develop in situ calcium phosphate(Ca P)coating on the sample surfaces.In addition,the treated samples recorded a reduced degradation rate in the SBF compared to untreated samples.Thus,acid pickling is suggested as an effective surface treatment method to tailor the biomineralization and degradation behaviour of the Mg-Ca alloy in the physiological environment.
基金the financial support by the National Natural Science Foundation of China(NSFC)(Grant Nos.52178319 and 52108307)the Natural Science Foundation of Fujian Province,China(Grant No.2022J05127).
文摘Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this paper.Two series of biomineralization tests in solution and sand column,respectively,were conducted.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) crystals.The experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this study.The difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).
基金Supported by the National Natural Science Foundation of China(No.41706165)the Fundamental Research Funds of Shandong University(No.2019HW022)。
文摘Magnetotactic bacteria can orientate in the Earth’s magnetic field to search for their preferred microoxic environments,which is achieved by their unique organelles,the magnetosomes.Magnetosomes contain nanometer-sized crystal particles of magnetic iron minerals,which are only synthesized in lowoxygen environments.Although the mechanism of aerobic repression for magnetosome biomineralization has not yet fully understood,a series of studies have verified that redox modulation is pivotal for magnetosome formation.In this review,these advances in redox modulation for magnetosome biosynthesis are highlighted,mainly including respiration pathway enzymes,specific magnetosome-associated redox proteins,and oxygen-or nitrate-sensing regulators.Furthermore,their relationship during magnetosome biomineralization is discussed to give insight into redox control and biomineralization and inspire potential solutions for the application of respiration pathways to improve the yields of magnetosome.
基金supported by National Science and Technology Major Special Project-Major New Drug Creation(2019ZX09301-112)Shandong Natural Science Foundation(ZR2020QH351)+1 种基金Shandong Provincial Program of Taishan Industrial Experts(2019TSCYCX-31)the Fundamental Research Funds of Shandong University(2020GN091)
文摘Growing evidence suggests that the presence of cancer stem cells(CSCs)is a major challenge in current tumor treatments,especially the transition from non-CSCs to differentiation of CSCs for evading conventional therapies and driving metastasis.Here we propose a therapeutic strategy of synergistic differentiation therapy and phototherapy to induce differentiation of CSCs into mature tumor cells by differentiation inducers and synergistic elimination of them and normal cancer cells through phototherapy.In this work,we synthesized a biomimetic nanoplatform loaded with IR-780 and all-trans retinoic acid(ATRA)via biomineralization.This method can integrate aluminum ions into small-sized protein carriers to form nanoclusters,which undergo responsive degradation under acidic conditions and facilitate deep tumor penetration.With the help of CSC differentiation induced by ATRA,IR-780 inhibited the self-renewal of CSCs and cancer progression by generating hyperthermia and reactive oxygen species in a synergistic manner.Furthermore,ATRA can boost immunogenic cell death induced by phototherapy,thereby strongly causing a systemic anti-tumor immune response and efficiently eliminating CSCs and tumor cells.Taken together,this dual strategy represents a new paradigm of targeted eradication of CSCs and tumors by inducing CSC differentiation,improving photothermal therapy/photodynamic therapy and enhancing antitumor immunity.
文摘Pyritic stromatolite, a rich pyrite ore, is scattered as reef masses in sedex deposits of the Proterozoic Yanshan rift trough. The pyritic stromatolite consists of a core and alternating concentric rims of light colloidal pyrite and dark organic materials. The concentric rims are cemented together by trichomes highly similar to the trichomic microorganisms inhabiting substantively around the black chimneys on the current sea beds while the core is composed chiefly of groups of thermophilous sulphur bacteria. Biomarkers for the molecules of pyritic stromatolite include pristane, phytane, regular isoprenoids paraffin, methyl-heptadecyl, and so on. This study reveals the existence of methane-yielding bacteria in the pyritic stromatolite and reflects the evolution of thermophilous thallophyta.
基金supported by the National Natural Science Foundation of China (No. 21876123)the Fundamental Research Funds for the Central Universities and the key Research and Development Program of Sichuan Province, China (No. 2020YFN0127)
文摘As a biosorbent,algae are frequently used for the biotreatment or bioremediation of water contaminated by heavymetal or radionuclides.However,it is unclear that whether or not the biomineralization of these metal or radionuclides can be induced by algae in the process of bioremediation and what the mechanism is.In this work,Ankistrodsemus sp.has been used to treat the uranium-contaminated water,and more than 98%of uranium in the solution can be removed by the alga,when the initial uranium concentration ranges from 10 to 80 mg/L.Especially,an unusual phenomenon of algae-induced uranium biomineralization has been found in the process of uranium bioremediation and its mineralization mechanism has been explored bymultiple approaches.It is worth noticing that the biomineralization of uranium induced by Ankistrodsemus sp.is significantly affected by contact time and pH.Uranium is captured rapidly on the cell surface via complexation with the carboxylate radical,amino and amide groups of themicroalgae cells,which provides nucleation sites for the precipitation of insolubleminerals.Uranium stimulates Ankistrodsemus sp.to metabolize potassium ions(K+),which may endow algae with the ability to biomineralize uranium into the rose-like compreignacite(K_(2)[(UO_(2))6O_(4)(OH)_(6)]•8H_(2)O).As the time increased,the amorphous gradually converted into compreignacite crystals and a large number of crystals would expand over both inside and outside the cells.To the best of our knowledge,this is the first investigated microalgae with a time-dependent uranium biomineralization ability and superior tolerance to uranium.This work validates that Ankistrodsemus sp.is a promising alga for the treatment of uranium-contaminated wastewater.
基金the National Natural Science Foundation of China(No.81600911).
文摘Bone and teeth are derived from intrafibrillarly mineralized collagen fibrils as the second level of hierarchy.According to polymer-induced liquid-precursor process,using amorphous calcium phosphate precursor(ACP)is able to achieve intrafibrillar mineralization in the case of bone biomineral in vitro.Therefore,ACP precursors might be blended with any osteoconductive scaffold as a promising bone formation supplement for in-situ remineralization of collagens in bone.In this study,mesoporous silica nanoparticles with carboxyl-functionalized groups and ultra large-pores have been synthesized and used for the delivery of liquid like biomimetic precursors(ACP).The precursor delivery capacity of the nanoparticles was verified by the precursor release profile and successful mineralization of 2D and 3D collagen models.The nanoparticles could be completely degraded in 60 days and exhibited good biocompatibility as well.The successful translational strategy for biomineralization precursors showed that biomineralization precursor laden ultra large pore mesoporous silica possessed the potential as a versatile supplement in demineralized bone formation through the induction of intrafibrillar collagen mineralization.
基金Funded by the National Natural Science Foundation of China (No.30170270, 30200063)
文摘K16 and RGD-containing peptide was used to modify the surface of three-dimensional PLGA-（ASP-PEG） matrix, then the modified PLGA-（ASP-PEG） was incubated in modified simulated body fluid （SBF）. The biomineralization of the modified PLGA- （ASP-PEG） was explored, and the peptide was synthesized with solid phase synthesis technology and linked cova-lently to PLGA-（ASP-PEG） through cross-linker （Sulfo-LC-SPDP）, which was characterized with XPS. The modified PLGA-（ASP-PEG） （Experiment group, EG） and PLGA-（ASP-PEG） （Control group, CG） were all incubated into SBF for 10 d, and the growth of hydroxyapatite （HA） nanocrys-tals was confirmed with XRD, EDS and SEM. HPLC shows that peptide purity is 94.13%, while MS analysis shows that molecular value of peptide is 2741.26. Binding energy of the sulphur in EG was 164 eV is detected by XPS, and the ratio of carbon and sulphur is 99.746：0.1014. SEM analysis demonstrates the better growth of bonelike HA nanocrystals in EG than that in CG. The component of mineral in EG consisted mainly of hydroxyapatite containing low crystalline nanocrystals, and the Ca/P ratio is about 1.60, which is similar to that of natural bone, while the Ca/P ratio in CG is 1.52. PLGA-（ASP-PEG） modified with peptide provided enough functional groups for biomineralization, and possessed the bonelike structure.
基金This research was supported by the Youth Foundation of National Natural Science of China grant 49503048.
文摘Geological and geochemical studies and experiments on mineralization indicate that the source bed of the La' erma gold deposit in the south subbelt of the western Qinling Mountains is hydrothermal cherts in the Cambrian Taiyangding Group. Organic geochemical study of the cherts shows that the organic precursors intimately associated with gold are marine bacteria and algae. The gold content in chert,is positively correlated with the amount of bacterial and algal microfossils, and simulation experiments on biomineralization of modern bacteria and algae indicate that bacteria and algae played an important role in the formation of the La' erma gold deposit.
基金support from the National Natural Science Foundation of China(NSFC)(Grant Nos.52338007 and 52178319)the Joint Fund of the Technical R&D Program of Henan Province(Grant No.225200810005)the technical assistance from the Analytical and Testing Center of Huazhong University of Science and Technology.
文摘The one-phase-low-pH method is a simple,efficient,and user-friendly biogrouting technique that can effectively improve the biomineralization of enzyme-induced carbonate precipitation(EICP)using free urease enzyme.One of the most significant advantages of this method is its capacity to effectively delay calcium carbonate(CaCO3)precipitation by reducing the pH of the solution through the addition of acid.This prevents bioclogging during the biogrouting process and improves the biomineralization effect.However,the biomineralization of the one-phase-low-pH based EICP method may be influenced by the specific acid used.To investigate the impact of acid type on the one-phase-low-pH EICP method using crude soybean urease solution(CSUS),four types of acids,including hydrochloric acid(HCl),nitric acid(HNO_(3)),acetic acid(CH_(3)COOH),and lactic acid(C_(3)H_(6)O_(3)),were used to adjust the pH of CSUS.A series of macroscopic and microscopic experiments were conducted to evaluate the effect of acid type on the onephase-low-pH EICP method.The results indicate that the acid has an inhibition on the urease activity(UA)of CSUS.Among the acids tested,HNO_(3)exhibits the most pronounced inhibitory effect on the UA of CSUS,followed by HCl,and the least pronounced inhibitory effect for CH_(3)COOH and C3H6O_(3)under the same pH conditions.Meanwhile,CH_(3)COOH and C_(3)H_(6)O_(3)could provide a longer delay duration of CaCO_(3)precipitation than HNO_(3)and HCl.Therefore,the one-phase-low-pH EICP method based on CH_(3)COOH and C_(3)H_(6)O_(3)can significantly improve the effective biocementation depth compared to that based on HNO_(3)and HCl.Nevertheless,the different types of acids appear to have no obvious effect on the polymorph and crystalline of the precipitated CaCO_(3)crystals.
基金supported by National Natural Science Foundation of China(grant No.41376077)Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDB06020204)the National Key Basic Research Program of China(grant No.2013CB429703)
文摘The origin of ancient banded iron formation （BIF） has remained unclear for a long time. How the precipitation process occurred and what the environmental condition was have been widely discussed among scientists, because the period when the major BIFs deposited （-2.8 to 1.8Ga） is the same time when biosphere and atmosphere significantly changed. Based on the discovery of modern seafloor hydrothermal vents, it is possible that reductive environment controlled by vent system is related to the environment where BIF was deposited. According to matter source.
文摘Up to now, chemical synthesis routes only provide restricted opportunities for the formation of structured nano particles. In contrast, living microorganisms generate nano materials of well defined shapes by the precise control of biomineralization. Here we reveal new principles for the generation of functional nano materials through the process of biomineralization. We used the detoxification mechanism of the unicellular alga Scenedesmus obliquus to generate a techno logically interesting zinc-phosphate-based nano material. The algae were incubated in media with a sublethal zinc concentration (6.53 mg Zn dm-3) for 4 weeks. Using BF-and ADF-STEM imaging combined with analytical XEDS we could show that nano needles containing phosphorus and zinc were formed inside the living cells. Further more, the cells incubated with zinc show a strong fluorescence. Our findings indicate that the algae used polyphosphate bodies for detoxification of the zinc ions, leading to the generation of intracellular zinc-phosphate-based nano needles. Beside the technological application of this material, the fluorescent cells can be used for labeling of e.g. biological probes. This new experimental protocol for the production of an inorganic functional material can be applied also for other substances.
基金support by the National Natural Science Foundation of China(NSFC)(Grant No.52178319,52108307,52078236,51878313,51708243)the Natural Science Foundation of Fujian Province,China(Grant No.2022J05020,2022J05127).
文摘Heavy metal contamination of soil and water is one of the most prominent environmental issues worldwide.Through bioaccumulation and biomagnification of the food chain,heavy metals can be enriched hundreds of times and eventually enter the human body,posing a major threat to human health.Biomineralization has the greatest potential to become an efficient and environmentally friendly heavy metal remediation technology and has received much attention in recent decades.This review summarizes the latest progress of biomineralization technology on carbonate precipitation and phosphate precipitation in heavy metal remediation.Both microorganisms(including bacteria and fungi)and enzymes can induce carbonate and phosphate precipitation,converting the free heavy metal ions into insoluble salts.However,the mechanisms of the heavy metal remediation are significantly different.For example,urea hydrolysis,which occurs intracellularly when urease-producing bacteria(UPB)are used,is the most commonly used mechanism for carbonate precipitation based bioremediation.In contrast,phosphate solubilization by either enzymes or organic acids secreted by phosphate solubilizing bacteria(PSB)is extracellular,and both soluble and insoluble phosphorus can be decomposed by PSB.Moreover,some influencing factors such as the different species of microorganism,heavy metals and some environmental conditions that may affect the bioremediation of heavy metals were also summarized in this paper.The challenges of biomineralization based heavy metal remediation are also discussed.Based on the reviews of previous studies,a comprehensive understanding of heavy metal removal through microorganism can be increased,and thus promotes the applications of biomineralization technology in the treatment of large-scale heavy metal contaminated sites.
基金supported by the Natural Science Foundation of China(42007246)and the Fundamental Research Funds for the Central Universities.
文摘In this review paper,the applications of biomineralization in environmental geotechnics are analyzed.Three environmental geotechnics scenarios,namely heavy metal contamination immobilization and removal,waste and CO_(2)containment,and recycled use of industrial byproducts,are discussed and evaluated regarding current trends and prospects.The biomineralization process,specifically the Microbially Induced Carbonate Precipitation(MICP)technology,is an effective solution for immobilizing heavy metals through co-precipitation with calcium carbonate,with successful results in cleaning up contaminated soils.The nature of biomineralization enhances earth material strength and decreases permeability,making it suitable for waste and CO_(2)containment.Additionally,using industrial byproducts in MICP technology can improve the physical,mechanical,and hydraulic properties of earth materials,making it a potential solution for efficient waste utilization.In conclusion,the applications of biomineralization in environmental geotechnics hold great promise for solving various environmental problems.However,further research is needed to better understand the control and consistency of biomineralization processes,the durability of biominerals,the scale of applications,and environmental concerns.
