Overcoming the inhibitory effects of urea to improve the kinetics of microbial-induced calcium carbonate precipitation (MICCP) by Lysinibacillus sphaericus strain MB284.

Among different microbial-induced calcium carbonate precipitation (MICCP) mechanisms utilized for biomineralization, ureolysis leads to the greatest yields of calcium carbonate. Unfortunately, it is reported that urea-induced growth inhibition can delay urea hydrolysis but it is not clear how this affects MICCP kinetics. This study investigated the impact of urea addition on the MICCP performance of Lysinibacillus sphaericus MB284 not previously grown on urea (thereafter named bio-agents), compared with those previously cultured in urea-rich media (20 g/L) (hereafter named bio-agents+ or bio-agents-plus). While it was discovered that initial urea concentrations exceeding 3 g/L temporarily hindered cell growth and MICCP reactions for bio-agents, employing bio-agents+ accelerated the initiation of bacterial growth by 33% and led to a 1.46-fold increase in the initial yield of calcium carbonate in media containing 20 g/L of urea. The improved tolerance of bio-agents+ to urea is attributed to the presence of pre-produced endogenous urease, which serves to reduce the initial urea concentration, alleviate growth inhibition, and expedite biomineralization. Notably, elevating the initial concentration of bio-agents+ from OD600 of 0.01 to 1, housing a higher content of endogenous urease, accelerated the initiation of MICCP reactions and boosted the ultimate yield of biomineralization by 2.6 times while the media was supplemented with 20 g/L of urea. These results elucidate the advantages of employing bio-agents+ with higher initial cell concentrations to successfully mitigate the temporary inhibitory effects of urea on biomineralization kinetics, offering a promising strategy for accelerating the production of calcium carbonate for applications like bio self-healing of concrete.

Structural and Compositional Changes in Two Marine Shell Traditional Chinese Medicines: A Comparative Analysis Pre- and Post-Calcination.

BACKGROUND: Arcae concha and Meretricis concha cyclinae concha are two marine shellfish herbs with similar composition and efficacy, which are usually calcined and used clinically. OBJECTIVE: This study investigated variations in the inorganic and organic components of Arcae concha and Meretricis concha cyclinae concha from different production regions, both Arcae concha and Meretricis concha cyclinae concha. The aim was to enhance the understanding of these two types of marine shell traditional Chinese medicine (msTCM) and provide a foundation for their future development and application. METHOD: Spectroscopic techniques, including infrared spectroscopy, X-ray spectroscopy, and X-ray fluorescence spectroscopy, were used to analyze the calcium carbonate (CaCO3) crystal and trace elements. Thermogravimetric analysis was used to investigate the decomposition process during heating. The proteins were quantified using the BCA protein assay kit. Principal component analysis (PCA) was used to classify inorganic elements in the two marine shellfish traditional Chinese medicines. RESULTS: No significant differences were found among the various production regions. The crystal structure of CaCO3 in the raw products was aragonite, but it transformed into calcite after calcination. The contents of Ca, Na, Sr, and other inorganic elements were highest. The protein content was significantly reduced after calcination. Therefore, these factors cannot accurately reflect the internal quality of TCM, rendering qualitative identification challenging. CaCO3 dissolution in the decoction of Arcae concha and Meretricis concha cyclinae concha increased after calcination, aligning with the clinical application of calcined shell TCM. PCA revealed the inorganic elements in them, indicating that the variation in trace element composition among different drugs leads to differences in their therapeutic focus, which should be considered during usage. CONCLUSIONS: This study clarifies the composition and structure changes of corrugated and clam shell before and after calcining, and it lays the foundation for the comprehensive utilization of marine traditional Chinese medicine. HIGHLIGHTS: These technical representations reveal the differences between raw materials and processed products, which will provide support for the quality control of other shellfish TCM.

Microbial induced carbonate precipitation for remediation of heavy metals, ions and radioactive elements: A comprehensive exploration of prospective applications in water and soil treatment.

Improper disposal practices have caused environmental disruptions, possessing by heavy metal ions and radioactive elements in water and soil, where the innovative and sustainable remediation strategies are significantly imperative in last few decades. Microbially induced carbonate precipitation (MICP) has emerged as a pioneering technology for remediating contaminated soil and water. Generally, MICP employs urease-producing microorganisms to decompose urea (NH2CONH2) into ammonium (NH4+and carbon dioxide (CO2), thereby increasing pH levels and inducing carbonate precipitation (CO32-), and effectively removing remove contaminants. Nonetheless, the intricate mechanism underlying heavy metal mineralization poses a significant challenge, constraining its application in contaminants engineering, particularly in the context of prolonged heavy metal leaching over time and its efficacy in adverse environmental conditions. This review provides a comprehensive idea of recent development of MICP and its application in environmental engineering, examining metabolic pathways, mineral precipitation mechanisms, and environmental factors as well as providing future perspectives for commercial utilization. The use of ureolytic bacteria in MICP demonstrates cost-efficiency, environmental compatibility, and successful pollutant abatement over tradition bioremediation techniques, and bio-synthesis of nanoparticles. limitations such as large-scale application, elevated Ca2+levels in groundwater, and gradual contaminant release need to be overcome. The possible future research directions for MICP technology, emphasizing its potential in conventional remediation, CO2 sequestration, bio-material synthesis, and its role in reducing environmental impact for long-term economic benefits.

Physical Phenomena Governing Mineral Morphogenesis in Molluscan Nacre.

Mollusks, as well as many other living organisms, have the ability to shape mineral crystals into unconventional morphologies and to assemble them into complex functional mineral-organic structures, an observation that inspired tremendous research efforts in scientific and technological domains. Despite these, a biochemical toolkit that accounts for the formation of the vast variety of the observed mineral morphologies cannot be identified yet. Herein, phase-field modeling of molluscan nacre formation, an intensively studied biomineralization process, is used to identify key physical parameters that govern mineral morphogenesis. Manipulating such parameters, various nacre properties ranging from the morphology of a single mineral building block to that of the entire nacreous assembly are reproduced. The results support the hypothesis that the control over mineral morphogenesis in mineralized tissues happens via regulating the physico-chemical environment, in which biomineralization occurs: the organic content manipulates the geometric and thermodynamic boundary conditions, which in turn, determine the process of growth and the form of the biomineral phase. The approach developed here has the potential of providing explicit guidelines for the morphogenetic control of synthetically formed composite materials.

Size-dependent therapeutic efficiency of 223Ra-labeled calcium carbonate carriers for internal radionuclide therapy of breast cancer.

The size of drug carriers strongly affects their biodistribution, tissue penetration, and cellular uptake in vivo. As a result, when such carriers are loaded with therapeutic compounds, their size can influence the treatment outcomes. For internal α-radionuclide therapy, the carrier size is particularly important, because short-range α-emitters should be delivered to tumor volumes at a high dose rate without any side effects, i.e. off-target irradiation and toxicity. In this work, we aim to evaluate and compare the therapeutic efficiency of calcium carbonate (CaCO3) microparticles (MPs, >2 µm) and nanoparticles (NPs, <100 nm) labeled with radium-223 (223Ra) for internal α-radionuclide therapy against 4T1 breast cancer. To do this, we comprehensively study the internalization and penetration efficiency of these MPs and NPs, using 2D and 3D cell cultures. For further therapeutic tests, we develop and modify a chelator-free method for radiolabeling of CaCO3 MPs and NPs with 223Ra, improving their radiolabeling efficiency (>97%) and radiochemical stability (>97%). After intratumoral injection of 223Ra-labeled MPs and NPs, we demonstrate their different therapeutic efficiencies against a 4T1 tumor. In particular, 223Ra-labeled NPs show a tumor inhibition of approximately 85%, which is higher compared to 60% for 223Ra-labeled MPs. As a result, we can conclude that 223Ra-labeled NPs have a more suitable biodistribution within 4T1 tumors compared to 223Ra-labeled MPs. Thus, our study reveals that 223Ra-labeled CaCO3 NPs are highly promising for internal α-radionuclide therapy.

Phosphorus removal from urban wastewater through adsorption using biogenic calcium carbonate.

Phosphorus (P) removal from urban wastewater is increasingly relevant in the wastewater treatment sector. The present work aims to contribute to the study of the adsorption process as a P removal technology. Biogenic calcium carbonate from industrial eggshell waste prepared by milling and calcination was used as an adsorbent. Batch adsorption experiments were conducted using real wastewater with 40 mg P/L (orthophosphate), original pH 7.33, under stirring conditions (100 rpm). The adsorbent was characterized using SEM-EDS, XRD, and FTIR-ATR before and after adsorption. From an initial screening of calcination times (15, 30, 60, and 120 min) and considering a balance between P removal and energy saving, the adsorbent selected was eggshell calcined at 700 °C for 60 min. The Langmuir isotherms describe the experimental data with a maximum adsorption capacity of 4.57 mg P/g at 25 °C. The adsorption process reached equilibrium within 120 min for different dosages (5, 10, and 20 g/L at 25 °C). Batch experiments showed that SO42-, at a concentration of 2689 mg/L reduced the P adsorption selectivity for dosages ≤10 g/L at 25 °C. Characterization of the loaded adsorbent shows that P adsorption from real wastewater is mostly electrostatic attraction, with the contribution of ligand exchange and microprecipitation. The adsorption capacity and behavior of the selected adsorbent seem promising for P removal from urban wastewater compared with other low-cost adsorbents.

Self-assembled silk fibroin cross-linked with genipin supplements microbial carbonate precipitation in building material.

The process of microbially induced carbonate precipitation (MICP) is known to effectively improve engineering properties of building materials and so does silk fibroin (SF). Thus, in this study, an attempt was taken to see the improvement in sand, that is, basic building material coupled with MICP and SF. Urease producing Bacillus megaterium was utilized for MICP in Nutri-Calci medium. To improve the strength of SF itself in bacterial solution, it was cross-linked with genipin at the optimized concentration of 3.12 mg/mL. The Fourier transform infrared (FTIR) spectra confirmed the crosslinking of SF with genipin in bacterial solution. In order to understand how such cross-linking can improve engineering properties, sand moulds of 50 mm3 dimension were prepared that resulted in 35% and 55% more compressive strength than the one prepared with bacterial solution with SF and bacterial solution only, respectively with higher calcite content in former one. The FTIR, SEM, x-ray powder diffraction spectrometry and x-ray photoelectron spectroscopy analyses confirmed higher biomineral precipitation in bacterial solution coupled with genipin cross-linked SF. As the process of MICP is proven to replace cement partially from concrete without negatively influence mechanical properties, SF cross-linked with genipin can provide additional significance in developing low-carbon cement-based composites.

Functional mimicry of sea urchin biomineralization proteins with CaCO3-binding peptides selected by phage display.

The intricate process of biomineralization, e.g. in sea urchins, involves the precise interplay of highly regulated mineralization proteins and the spatiotemporal coordination achieved through compartmentalization. However, the investigation of biomineralization effector molecules, e.g. proteins, is challenging, due to their very low abundance. Therefore, we investigate the functional mimicry in the bioinspired precipitation of calcium carbonate (CaCO3) with artificial peptides selected from a peptide library by phage display based on peptide-binding to calcite and aragonite, respectively. The structure-directing effects of the identified peptides were compared to those of natural protein mixes isolated from skeletal (test) structures of two sea urchin species (Arbacia lixula and Paracentrotus lividus). The calcium carbonate samples deposited in the absence or presence of peptides were analyzed with a set of complementary techniques with regard to morphology, polymorph, and nanostructural motifs. Remarkably, some of the CaCO3-binding peptides induced morphological features in calcite that appeared similar to those obtained in the presence of the natural protein mixes. Many of the peptides identified as most effective in exerting a structure-directing effect on calcium carbonate crystallization were rich in basic amino acid residues. Hence, our in vitro mineralization study further highlights the important, but often neglected, role of positively charged soluble organic matrices associated with biological and bioinspired CaCO3 deposition.

Uranium Speciation in a Chalky Soil.

In this article, the speciation and behavior of anthropogenic metallic uranium deposited on natural soil are approached by combining EXAFS (extended X-ray absorption fine structure) and TRLFS (time-resolved laser-induced fluorescence spectroscopy). First, uranium (uranyl) speciation was determined along the vertical profile of the soil and bedrock by linear combination fitting of the EXAFS spectra. It shows that uranium migration is strongly limited by the sorption reaction onto soil and rock constituents, mainly mineral carbonates and organic matter. Second, uranium sorption isotherms were established for calcite, chalk, and chalky soil materials along with EXAFS and TRLFS analysis. The presence of at least two adsorption complexes of uranyl onto carbonate materials (calcite) could be inferred from TRLFS. The first uranyl tricarbonate complex has a liebigite-type structure and is dominant for low loads on the carbonate surface (<10 mgU/kg(rock)). The second uranyl complex is incorporated into the calcite for intermediate (∼10 to 100 mgU/kg(rock)) to high (high: >100 mgU/kg(rock)) loads. Finally, the presence of a uranium-humic substance complex in subsurface soil materials was underlined in the EXAFS analysis by the occurrence of both monodentate and bidentate carboxylate (or/and carbonate) functions and confirmed by sorption isotherms in the presence of humic acid. This observation is of particular interest since humic substances may be mobilized from soil, potentially enhancing uranium migration under colloidal form.

Eco-friendly soil stabilization method using fish bone as cement material.

The method of soil improvement by calcium phosphate precipitation is a novel, environmentally friendly, and non-toxic technique. Such technology provides advantages over ureolytic induced calcite precipitation (UICP), the most popular and widely used method in the field of geotechnical engineering. In this paper, an investigation of the consolidation of fine and coarse sand samples by enzyme induced calcium phosphate precipitation (EICPP) was carried out. Tuna bones were used as an alternative source of calcium and phosphorus ions, as one of the most popular fish species in Japan and the main source of food industry waste. Unconfined compressive strength (UCS) of the samples after 21 days of daily injection of the solution showed an increase in strength up to 6,05 MPa in fine and up to 4,3 MPa in coarse sand samples. X-ray powder diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (SEM-EDS) analysis were performed to investigate the nature and type of deposition. Analyses confirmed that deposition is composed of brushite with needle-like crystals in the case of Toyoura sand and flower-like crystals in the case of Mikawa sand. SEM-EDS showed a presence of both, calcium, and phosphorus in the precipitate, indicating the presence of calcium phosphate compounds (CPCs). This study reveals that tuna bones are a rich source of calcium and phosphorus for EICPP, which results in a strengthening of silicate soil up to 3.4-6.05 MPa and is able to reduce ammonia emissions by 85.7 % - 97.5 % compared to UICP.

A novel and sustainable approach for biotransformation of phosphogypsum to calcium carbonate using urease producing Lysinibacillus sphaericus strain GUMP2.

Phosphogypsum (CaSO4) is produced as a waste by-product during phosphoric acid production in the fertilizer industry. Only 15% of worldwide phosphogypsum production is recycled, while 85% is stored in the vicinity of factories as huge piles resulting in environmental and health hazards. An extensively studied biotransformation of phosphogypsum to calcium carbonate or calcite (CaCO3) using sulfate reducing bacteria (SRBs) is a prolonged process and results in the formation of extremely hazardous H2S gas. Here we report for the first time a novel approach for biotransformation of phosphogypsum to CaCO3 using urease producing Lysinibacillus sphaericus strain GUMP2. The strain could effectively transform phosphogypsum to crystalline, bead-shaped CaCO3 precipitates. In a batch reactor with the PG loading rate of 60 g/L, 100% biotransformation was observed within seven days. After calcite recovery, the ammonium sulfate formed in the supernatant was recovered by precipitation. Urease-producing L. sphaericus strain GUMP2 could be used to remove the hazardous phosphogypsum from the environment by converting it to the industrially useful CaCO3 and ammonium sulfate, a valuable agricultural fertilizer. This novel and sustainable approach could be a promising solution for the hazardous phosphogypsum in the phosphoric acid industries.

Multi-scale approach to assess total porosity and pore size in four different kinds of carbonate rocks.

Petroleum is, at present, still the main energy source in the world. Most of it is stored in carbonate rock reservoirs with complex inner structures and pores ranging from nanometers to dozens of meters. Knowing the rock's entire pore network is indispensable to perform an effective petroleum extraction. X-ray microtomography, a technique that generates images from samples' inner structure and a powerful tool to evaluate the 3D pore network, was employed in this scientific research to scan four kinds of carbonate rocks (Dolomite, Desert Pink, Indiana, and Winterset) in five different pore scales (90 µm, 13 µm, 5.5 µm, 1.0 µm, and 65 nm). A multi-scale approach based on the number of pores was applied to integrate different pore scale data and assess the total porosity as well as each sample pore size distribution. The results were compared to classical Mercury Injection Capillary Pressure (MICP) results, demonstrating a fair agreement in total porosity in the two samples. Multi-scale porosity of the Dolomite sample was 17.7% against (18.9 ± 2.1)% of the MICP porosity. The Winterset sample had multi-scale porosity of 26.2%, while MICP porosity was (31.2 ± 0.6)%. Pore size distribution results were rather satisfactory, especially when overlapping regions in different scales were compared. In general, the multi-scale approach showed good potential. It still needs further evaluation to fine-tune some procedures and fluid flow simulation tests but might become a useful tool to study reservoir rocks with a wide range of pore sizes, such as carbonate rocks.

Calcium carbonate-modified plant sporopollen capsule as an eco-friendly microvehicle for controlled release of pesticide.

BACKGROUND: In this work, natural club moss (Lycopodium clavatum, LC) spores with a porous surface morphology and highly uniform size distribution were engineered into controlled-release microvehicles for pesticide delivery. As a proof of concept, a widely used fungicide, fluazinam (FLU), was successfully loaded into LC spores and then modified with different amounts of CaCO3 (CaC) to extend the efficacy duration of FLU. Significantly, as the control target of FLU, clubroot disease is a worldwide destructive disease of cruciferous crops, and its development is favored by acidic soils and can be suppressed at high Ca concentrations. RESULTS: Fabricated FLU@LC-CaC microcapsules, FLU loading and CaCO3 deposition were systematically characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The as-prepared FLU@LC-CaC microcapsules showed sustained-release behaviors and were potentially able to supplement the Ca concentration in acidic environments. This approach synergistically enhanced in vivo bioactivity for the on-demand control of clubroot disease. An in vivo bioassay revealed that the control efficacy of FLU@LC-CaC against clubroot disease in pak choi (Brassica chinensis) (66.4%) was 1.7-fold higher than that of a commercial FLU suspension concentrate (38.2%) over the course of the cultivation period (35 days). CONCLUSIONS: This work provides new ideas not only for developing eco-friendly and scalable microvehicles for pesticide delivery based on natural sporopollen, but also for unconventional research perspectives in on-demand pest management based on their occurrence characteristics. © 2022 Society of Chemical Industry.

Experimental dissolution of fossil bone under variable pH conditions.

Fossils exposed at the surface are an integral component of the paleontologic record and provide an archive of past life. However, it is widely known that fossils are not stable indefinitely upon exposure to surface conditions such as physical, chemical, and biological processes, and this last phase of taphonomy is poorly understood. Studies regarding the longevity of fossils subject to weathering, such as acidic precipitation, are absent in the literature. The goal of this study was to experimentally determine vertebrate fossil dissolution rates under variable pH conditions in a controlled laboratory setting. It was hypothesized that fossils would dissolve within acidic solutions and do so at an increasing rate when exposed to increasingly acidic solutions. The experiments were conducted on three fossil vertebrae in triplicate in closed reaction vessels at pH 4, 5, and 6. The fossils were completely submerged for 21 days in a tap water solution with the pH adjusted using 0.1N hydrochloric acid (HCl). Fossil dissolution was quantified by changes to: (1) fossil mass; (2) elemental chemistry of water and fossils with inductively coupled plasma mass spectrometry (ICP-MS); (3) fossil mineralogy with X-ray diffraction (XRD); and (4) histologic structures with thin section analyses. All fossils exhibited mass loss, which increased with decreasing pH conditions, and was greatest under pH 4 (477 to 803 mg loss). The elemental analyses with ICP-MS indicated an increase of both calcium (maximum increase of 315 ppm) and phosphorus (increase of 18 ppm) in aqueous solutions with increasing pH and a loss of those same elements from the fossils (maximum loss of 10 ppm Ca and 6 ppm P). XRD revealed loss of gypsum in all post-dissolution samples. Taken together, the results of ICP-MS and XRD suggest dissolution of the primary mineral phases, including hydroxylapatite, and secondary phases, particularly calcite and gypsum, resulting in an estimated mass loss at pH 4 of 23 to 28 mg per day. Thin section analysis showed degradation of both cortical and trabecular bone in all post-dissolution images, demonstrating physical changes to the fossils as a result of water-rock interactions. These findings constitute the first quantitative analysis of fossil dissolution rates and provide insights into this last stage of taphonomy, addressing a largely understudied potential bias in the vertebrate fossil record.

Preferential Adsorption of Prominent Amino Acids in the Urease Enzyme of Sporosarcina pasteurii on Arid Soil Components: A Periodic DFT Study.

The urease enzyme is commonly used in microbially induced carbonate precipitation (MICP) and enzyme-induced carbonate precipitation (EICP) to heal and strengthen soil. Improving our understanding of the adsorption of the urease enzyme with various soil surfaces can lead to advancements in the MICP and EICP engineering methods as well as other areas of soil science. In this work, we use density functional theory (DFT) to investigate the urease enzyme's binding ability with four common arid soil components: quartz, corundum, albite, and hematite. As the urease enzyme cannot directly be simulated with DFT due to its size, the amino acids comprising at least 5% of the urease enzyme were simulated instead. An adsorption model incorporating the Gibbs free energy was used to determine the existence of amino acid-mineral binding modes. It was found that the nine simulated amino acids bind preferentially to the different soil components. Alanine favors corundum, glycine and threonine favor hematite, and aspartic acid favors albite. It was found that, under the standard environmental conditions considered here, amino acid binding to quartz is unfavorable. In the polymeric form where the side chains would dominate the binding interactions, hematite favors aspartic acid through its R-OH group and corundum favors glutamic acid through its R-Ket group. Overall, our model predicts that the urease enzyme produced by Sporosarcina pasteurii can bind to various oxides found in arid soil through its alanine, glycine, aspartic/glutamic acid, or threonine residues.

Synthesis of an organic-inorganic composite from calcium carbonate and Kraft lignin and its use as carrier material for controlled release of semiochemical agents.

The control of pests in agricultural systems is currently based on the widespread use of pesticides that efficiently control pests but have negative effects on the environment and humans. Thus, several studies have been conducted to develop alternative sustainable ways to control pests in agriculture. The use of semiochemicals presents a good alternative to develop a sustainable tool monitoring and control insect pests in crops areas. The dispensing carriers of semiochemicals are typically made of non-degradable material, often petroleum derivatives such as butyl rubber, that become polluting waste after application. To develop a biodegradable and low-cost dispenser for semiochemicals, particles of CaCO3 and a CaCO3/Kraft lignin composite were synthesized using CO2 bubbling, characterized and evaluated for 30 days as a dispenser of the limonene molecule, which is a common semiochemical in plants and also pheromone component is some insect species, such as the lesser mealworm Alphitobius diaperinus. Furthermore, limonene is volatile molecule that is easy to acquire and low-cost, which makes it an ideal semiochemical to evaluate the potential of the CaCO3 particles and CaCO3/Kraft lignin composite as a semiochemical dispenser for use in agriculture. The pure calcium carbonate I, pure calcium carbonate II, and composite I synthesized particles presented a larger specific surface area than the other composites. All the particles evaluated showed a slow limonene release rate between the 5th and 30th days evaluated, indicating the potential of these materials as pheromone dispensers. The composites with higher specific surface area, calcium carbonate II (19.5 m2/g) and composite I (23.1 m2/g), released a higher level of limonene during the 30 days evaluated.

Microbial induced calcite precipitation can consolidate martian and lunar regolith simulants.

We demonstrate that Microbial Induced Calcite Precipitation (MICP) can be utilized for creation of consolidates of Martian Simulant Soil (MSS) and Lunar Simulant Soil (LSS) in the form of a 'brick'. A urease producer bacterium, Sporosarcina pasteurii, was used to induce the MICP process for the both simulant soils. An admixture of guar gum as an organic polymer and NiCl2, as bio- catalyst to enhance urease activity, was introduced to increase the compressive strength of the biologically grown bricks. A casting method was utilized for a slurry consisting of the appropriate simulant soil and microbe; the slurry over a few days consolidated in the form of a 'brick' of the desired shape. In case of MSS, maximum strength of 3.3 MPa was obtained with 10mM NiCl2 and 1% guar gum supplementation whereas in case of LSS maximum strength of 5.65 Mpa was obtained with 1% guar gum supplementation and 10mM NiCl2. MICP mediated consolidation of the simulant soil was confirmed with field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and thermogravimetry (TG). Our work demonstrates a biological approach with an explicit casting method towards manufacturing of consolidated structures using extra-terrestrial regolith simulant; this is a promising route for in situ development of structural elements on the extra-terrestrial habitats.

Investigation of differential levels of phosphorus fixation in dolomite and calcium carbonate amended red soil.

BACKGROUND: The pH adjustment of acidic red soils with lime materials is beneficial for the reduction of phosphorus (P) fixation. However, the reasons for varying levels of P activation after adding different lime materials have not been fully investigated. Therefore, this study examined changes in soil labile P and P forms after phosphate application to calcium carbonate (CaCO3 ) and dolomite amended red soil during a 120-day incubation period. Also change of P sorption properties in the amended soil samples from day 120 were examined through a sorption-desorption experiment. RESULTS: The increase of soil H2 O-P and NaHCO3 -P in the CaCO3 and dolomite amended soil treatments was mainly ascribed to the decline of the NaOH-P. However, when compared with the control treatment after 120 days, soil Olsen-P significantly increased by 34% and 66% in the CaCO3 and dolomite treatments. The Hedley P fractionation results demonstrated that the CaCO3 application caused a notable increase of HCl-P (stable Ca-P), which was 88.4% higher than that in the dolomite treatment. However, the formation of stable P was strongly suppressed in the dolomite treatment due to the presence of magnesium (Mg), which was identified by the negative relationship between M3-Mg and HCl-P. In line with these findings, P sorption-desorption work showed weaker P binding energy in the dolomite treatment relative to the CaCO3 treatment. CONCLUSION: In terms of increasing P availability in red soil, this study suggests that dolomite should be used to substitute CaCO3 in order to reduce the soil P fixation. © 2021 Society of Chemical Industry.

Tumor-killing nanoreactors fueled by tumor debris can enhance radiofrequency ablation therapy and boost antitumor immune responses.

Radiofrequency ablation (RFA) is clinically adopted to destruct solid tumors, but is often incapable of completely ablating large tumors and those with multiple metastatic sites. Here we develop a CaCO3-assisted double emulsion method to encapsulate lipoxidase and hemin with poly(lactic-co-glycolic acid) (PLGA) to enhance RFA. We show the HLCaP nanoreactors (NRs) with pH-dependent catalytic capacity can continuously produce cytotoxic lipid radicals via the lipid peroxidation chain reaction using cancer cell debris as the fuel. Upon being fixed inside the residual tumors post RFA, HLCaP NRs exhibit a suppression effect on residual tumors in mice and rabbits by triggering ferroptosis. Moreover, treatment with HLCaP NRs post RFA can prime antitumor immunity to effectively suppress the growth of both residual and metastatic tumors, also in combination with immune checkpoint blockade. This work highlights that tumor-debris-fueled nanoreactors can benefit RFA by inhibiting tumor recurrence and preventing tumor metastasis.

Formulation and Characterization of Calcium-Fortified Jelly and Its Proximate Composition and Sensory Analysis.

Calcium is a dynamic mineral. Recent discoveries designate that low intake of calcium generates deficiencies and path to other diseases. Food fortification could play a key role to overcome this problem. To cope with this deficiency problem, jellies were formulated with food-grade calcium salts and chicken eggshell powder. In the present study, three different concentrations of calcium salts, as well as eggshell powder were used to formulate jellies. The results of the sensory evaluation indicated that the two jelly products (A&D) in the current study were suitable for consumers. Results of Atomic Absorption Spectrophotometer revealed Jelly A and jelly D had 151±0.05 ppm and 133±0.06 ppm calcium concentration, respectively. Proximate analysis of Jelly A showed that it has 6.0±0.01% ash, 9.2±0.1% moisture, 0.4±0.01 g crude protein, 82.79±0.001 g crude fiber, and 0.61±0.001 g crude fat, while the jelly D that was made with chicken eggshell powder exhibited 6.0±0.01% ash, 10.1±0.1% moisture, 0.5±0.01 g protein, 84.54±0.01 g crude fiber and 1.61±0.01 g crude fat. Therefore, these two jelly A & D were greatly appreciated among other attributes. In spite of naturally available calcium-rich sources, calcium-fortified jellies can be consumed by individuals who are incapable to take sufficient calcium from their diet.