[Objective] This study systematically reviews the research trends in microbially induced calcium carbonate precipitation (MICP) over the past 25 years. Through bibliometric analysis, we aim to elucidate the developmental trajectory, research hotspots, and academic impact distribution of MICP, offering data-driven insights for researchers and proposing strategic priorities for future studies. [Methods] A comprehensive dataset of 1 947 publications was extracted from the Web of Science Core Collection (1999-2024). Bibliometric analysis and CiteSpace visualization tools were employed to quantify publication volume, authorship patterns, country/institutional contributions, and keywords dynamics. Time-series analysis and network mapping were integrated to decode the evolutionary pathways and interdisciplinary frontiers of the field. [Results] Annual MICP publications exhibit sustained growth, with China emerging as the dominant contributor, accounting for 47.71% of global output. Leading institutions such as Nanyang Technological University, Chinese Academy of Sciences, Southeast University, and Chongqing University demonstrate strong academic influence through high publication output and citation frequency. The research hotspots are primarily concentrated in soil improvement, self-healing concrete, and bioremediation. Keywords clustering analysis reveals emerging interdisciplinary frontiers at the intersection of environmental geotechnics and biomaterials applications. [Conclusion] MICP research has entered a phase of rapid multidisciplinary integration, with China leading global advancements. Future efforts should prioritize fundamental studies on bio-mineral interaction mechanisms, accelerate MICP applications in environmental remediation and smart materials, and develop green, sustainable processes to enhance its role in carbon neutrality and ecological engineering.

[Objective] To screen CO₂-fixing microbial strains in grassland soil, clarify their physiological and biochemical characteristics, and determine their optimal CO₂ fixation conditions, providing a theoretical basis for understanding the mechanisms of soil CO₂ fixation and enhancing grassland soil carbon sink. [Methods] The carbon-free solid medium and the dilution plating method were employed to isolate CO₂-fixing microbial strains from grassland soil in the Loess Plateau. The strains were identified via 16S rRNA gene sequencing. Physiological and biochemical characteristics of the strains were determined by Gram staining and starch hydrolysis, indole production, methyl red, and lactic acid fermentation tests. Culture experiments with carbon-free liquid medium and sterilized soil were carried out to assess the CO₂ fixation efficiency under varying temperatures (20-40 ℃), soil moisture levels (3.00%-27.00%), and the presence of electron donors (NaNO₂ and Na₂S). [Results] Nine bacterial strains with effective CO₂ fixation were isolated, belonging to Bacillus, Streptomyces, Sinorhizobium, Agrobacterium, Enterobacter, Brevundimonas, and Prolinoborus. Among them, strains A4 (Agrobacterium) and A7 (Brevundimonas) exhibited the highest CO₂ fixation efficiency (P<0.05), both being Gram-positive. Optimal conditions for CO₂ fixation of the nine strains were 25-30 ℃ and soil moisture of 3.00%, 15.00%, or 27.00% (P<0.05). Electron donor supplementation enhanced CO₂ fixation efficiency, and the enhancement effect followed the order: single addition of NaNO₂>single addition of Na₂S>co-addition of NaNO₂+Na₂S (P<0.05). [Conclusion] This study identified the dominant CO₂-fixing microbial strains and the conditions suitable for CO₂ fixation, providing a theoretical basis and technical support for enhancing the carbon sink of the terrestrial ecosystem on the Loess Plateau and mitigating the greenhouse effect.

[Objective] Roseobacter play a significant ecological role in the material cycling and energy flow of marine ecosystems. However, their environmental responses on long time scales and community assembly mechanisms remain unclear. We collected samples over 60 consecutive weeks from the coastal waters near Qingdao to investigate the annual dynamics, environmental responses, and community assembly mechanisms of free-living and particle-associated Roseobacter. [Methods] The 16S rRNA gene amplicon sequencing was performed for the surface seawater samples to reveal the seasonal diversity variations of Roseobacter groups with different lifestyles. Furthermore, the correlations of Roseobacter with various environmental factors and the community assembly mechanisms were explored. [Results] In the surface seawater of the coastal zone, the relative abundance of Roseobacter in total bacteria and archaea exhibited significant seasonal fluctuations (2.64%-34.10%), with being markedly higher in winter and spring than in summer and autumn. Based on the temporal distribution patterns, Roseobacter groups can be classified into summer-autumn, winter-spring, and outbreak growth types. The free-living Roseobacter groups showed more pronounced seasonal patterns, while the particle-associated groups showed higher diversity. Temperature, inorganic nitrogen, and inorganic phosphorus were the main environmental factors influencing Roseobacter diversity, with their explanatory power on particle-associated groups (16.82%) being higher than that on free-living groups (9.06%). In terms of community assembly, deterministic processes had a greater impact on particle-associated Roseobacter groups, indicating that environmental changes had more significant effects on these groups. [Conclusion] This study, by examining the dynamic changes and environmental driving mechanisms of Roseobacter at a fine time scale, reveals their seasonal distribution patterns and provides scientific insights for understanding the spatiotemporal dynamics and ecological functions of this crucial marine bacterial group.

[Objective] A Talaromyces purpureogenus strain with solubilizing effects on tricalcium phosphate and calcium phytate was screened from the rhizosphere soil of maize and named XZY3PSF. To promote the application of this strain in serving agricultural production, we optimized the culture conditions for phosphorus solubilization of this strain and studied the effects of this strain on the growth and quality of red cluster pepper. [Methods] We evaluated the solubilizing effects of strain XZY3PSF on Ca₃(PO₄)₂, FePO₄, AlPO₄, phosphate rock powder, soybean lecithin, and egg yolk by measuring the available phosphorus content in the solution after liquid shaking culture. The effects of carbon source, nitrogen source, pH, and liquid loading volume on the phosphorus solubilization of this strain were studied. Pot experiments were carried out in a greenhouse to evaluate the effects of this strain on the growth and fruit quality of red cluster pepper. [Results] The carbon sources used by the strain were in an order of fructose>glucose>maltose>sucrose, and the nitrogen sources followed an order of ammonium chloride>ammonium nitrate>ammonium sulfate>potassium nitrate>urea. The phosphorus-solubilizing ability of the strain was higher under the condition of initial pH 6.0-7.0, and it was not affected by the liquid loading volume. The strain achieved higher phosphorus solubilization with tricalcium phosphate and phosphate rock powder as the phosphorus sources. With tricalcium phosphate as the phosphorus source, the strain showed the highest phosphorus solubilization on days 5, which was higher than that with other phosphorus sources (P<0.01). With phosphate rock powder as the phosphorus source, the strain showed the highest phosphorus solubilization on days 21 (P<0.01). Compared with the application of compound fertilizer, the inoculation of this strain increased the plant height, yield, vitamin C content, and total capsaicinoid content of red cluster pepper (P<0.05). The results of Pearson correlation analysis showed that the phosphorus solubilization of strain XZY3PSF in the culture medium with different nitrogen or carbon sources was negatively correlated with pH and the dry weight of mycelia. The capsaicinoid content was positively correlated with vitamin C and sugar content of pepper fruits. [Conclusion] Strain XZY3PSF has a strong ability to solubilize phosphorus, especially aluminum phosphate and iron phosphate, while improving the main nutritional indicators of crops. It is hypothesized that the strain will have a strong ability to solubilize phosphorus in the laterite soil in southern China. These findings lay a foundation for subsequent application of this strain in the fieled.

Cryptococcus neoformans is a common opportunistic pathogen, exhibiting pronounced neurotropism that often results in cryptococcal meningitis. Its invasive ability is closely associated with multiple factors, including capsular polysaccharides, melanin, hydrolases, and adaptability to the host environment. Conventional diagnostic methods such as fungal culture and India ink staining, though still in use, have notable limitations, whereas emerging techniques like molecular diagnostics, imaging technologies, and biochips have significantly enhanced the diagnostic accuracy and sensitivity. In clinical treatment, amphotericin B and fluconazole are widely used as first-line antifungals, while the resistance to azoles is a growing problem and results in an elevated rate of clinical treatment failure. This is mainly attributed to target alterations, upregulation of efflux pump expression and genomic ploidy changes. Recent studies on virulence factors and resistance mechanisms have driven the development of novel antifungal therapies, including drug repurposing, novel drug development, and innovative drug delivery strategies. This article reviews the latest research in the virulence factors, diagnostic techniques, antifungal resistance mechanisms, and therapeutic development of C. neoformans, providing insights into the clinical management of cryptococcosis.

[Objective] This study characterized a novel esterase EstE from Streptomyces griseus by heterologous expression in Escherichia coli and systematically evaluates its thermostability, alkaline stability, and the effects of various additives (metal ions, detergents, and organic solvents) on its enzymatic activity to explore its potential for industrial applications. [Methods] We synthesized the gene estE' encoding the same amino acid sequence as the native gene by optimizing the original sequence of estE from S. griseus. We then constructed the recombinant plasmid carrying the optimized gene by ligating the gene into the pET-28b(+) vector. The esterase EstE was then expressed under the induction of IPTG and purified via Co²⁺ affinity chromatography. Furthermore, the enzymatic properties of the purified EstE were determined by the p-nitrophenol method, and bioinformatics analysis was performed for this enzyme. [Results] EstE consisted of 289 amino acid residues, with a molecular weight of 31.6 kDa. It belonged to the GDS(L) family, with Ser¹⁶, Asp¹⁹⁴, and His²²⁴ forming its catalytic triad. The enzyme showed the optimal activity at 40 ℃ and pH 8.5, with the highest catalytic efficiency (specific activity of 61.03 U/mg) observed in the case of p-nitrophenyl acetate as a substrate. EstE demonstrated robust thermostability, with the relative activity of 50% after 156.11 h of incubation at 40 ℃ and 2.67 h of incubation at 100 ℃. Moreover, it showed excellent alkaline stability, with the relative activity exceeding 80% after incubation at pH 8.5 for 100 h. In addition, this enzyme exhibited excellent tolerance to organic solvents, maintaining stable activity in the presence of 30% DMSO. [Conclusion] A novel esterase EstE from S. griseus is successfully obtained through heterologous expression, demonstrating excellent catalytic properties, thermostability, alkaline stability, and organic solvent tolerance, positioning it as a promising candidate for industrial applications.

As autotoxic substances secreted by plant roots, phenolic acids such as p-hydroxybenzoic acid (PHBA), are the main factors causing continuous cropping obstacles. [Objective] To study the effects of Microbacterium aurantiacum on the growth of tomato plants and the microbial community structure in rhizosphere soil under PHBA stress. [Methods] We irrigated tomato rhizosphere with the suspension of M. aurantiacum GX14001 and then measured the growth traits of tomato plants and the soil microbial community changes in the rhizosphere soil. [Results] Under the PHBA treatment, GX14001 significantly promoted the growth of tomato plants, increasing the leaf area, stem diameter, and plant height by 244.0%, 156.5%, and 128.0%, respectively. GX14001 increased the richness but did not cause changes in the diversity of bacteria in the rhizosphere soil. Meanwhile, it decreased the richness and diversity of fungi in the rhizosphere soil. At the phylum level, compared with the control group, the GX14001 group showed increased relative abundance of Actinobacteriota, Chloroflexi, and Proteobacteria, with Ascomycetes as the dominant fungal phylum. [Conclusion] M. aurantiacum GX14001 promotes the growth of tomato plants by changing the microbial community structure in the rhizosphere soil. It increases the relative abundance of beneficial microorganisms in the soil to create a favorable environment for tomato growth.

[Objective] Vibrio parahaemolyticus is a major foodborne pathogen that causes acute gastroenteritis in humans. Here, we aim to decipher the mechanisms by which the histidine kinase EnvZ regulates the swarming motility and biofilm formation of V. parahaemolyticus. [Methods] The plasmids pBAD24 and pMal carrying inducible promoters were used to construct the plasmids carrying target genes for overexpression. The recombinant plasmids were introduced into the wild-type strain (WT) and envZ-deleted strain (ΔenvZ) of V. parahaemolyticus. Swarming plates were prepared to measure swarming motility, while biofilm formation was detected by crystal violet staining. The RT-qPCR and bioluminescence reporter assays were employed to explore the mechanisms by which EnvZ regulated the expression of downstream genes. [Results] The swarming motility of ΔenvZ was significantly lower than that of WT, while the introduction of the pBAD24-envZ plasmid into ΔenvZ restored its swarming ability. The transcription levels of the lateral flagellar genes were positively correlated with the swarming motility. The promoter activities of P _scrABC -lux in ΔenvZ and ΔenvZΔompR were lower than those in WT and ΔompR. The swarming ability of ΔenvZ was significantly increased when the Scr system was overexpressed via the pMal-scrABC plasmid, while the overexpression of EnvZ in the strain without scrABC did not change the swarming motility. In addition, ΔenvZ exhibited a significant decrease in biofilm formation compared with WT. The pMal-envZ plasmid restored the biofilm formation of ΔenvZ to the level of WT, whereas the pMal-scrABC plasmid did not have this effect. The promoter activity of the extracellular polysaccharide operon (epsA-J) and the transcription levels of the extracellular polysaccharide genes in ΔenvZ were both significantly lower than those in WT. [Conclusion] The histidine kinase EnvZ enhances the swarming motility of V. parahaemolyticus by regulating the expression of the Scr system and promotes the biofilm formation by regulating the expression of extracellular polysaccharides.

[Objective] To provide environmental sustainable, safe, and efficacious management approaches for root rot impacting a range of crops in the unique agro-ecosystems of Gansu and Qinghai Provinces. [Methods] The plate confrontation method and the organophosphorus agar plate were used for preliminary screening of 305 strains of tested bacteria, and the strains obtained from preliminary screening were re-screened with the fermentation broth method. Subsequently, the nitrogen-fixing, phosphate-solubilizing, and potassium-solubilizing abilities of the strains were determined by the Kjeldahl method, ultraviolet spectrophotometry, and flame photometry, respectively. The siderophore-producing activity, the IAA content in the fermentation broth, as well as the acid, alkali, and salt tolerance of the strains, were determined by spectrophotometric methods. Finally, targeting the pathogens causing root rot in various crops in Gansu and Qinghai Provinces, bacterial consortia were constructed with different functional strains for disease prevention and plant growth promotion. The plant growth-promoting and antifungal effects of different consortia were evaluated, and the best consortium was selected. Furthermore, the 16S rRNA gene and gyrB of the strains in the best consortia were sequenced for identification. The root rot-preventing and plant growth-promoting effects of the best consortium were evaluated by the pot culture method. [Results] A total of 86 antagonistic strains and 134 phosphate-solubilizing strains were preliminarily screened out, and 20 antagonistic strains were selected after re-screening, among which strains K87 and LB17 demonstrated excellent broad-spectrum antifungal effects. Specifically, K87 showed inhibition rates of 87.53%, 74.90%, 75.15%, 79.69%, and 88.43% against Fusarium avenaceum, F. equiseti, F. oxysporum, F. solani, and Microdochium bolleyi, respectively. LB17 exhibited inhibition rates of 61.89%, 87.52%, and 87.23% against F. oxysporum, F. solani, and Bipolaris sorokiniana, respectively. Among the 8 strains with superior plant growth-promoting abilities, LB17 had the strongest siderophore-producing activity, with an iron carrier activity unit (su) value of 0.32, and K113 exhibited a good nitrogen-fixing capability, fixing nitrogen at a rate of 0.08 g/L. K87 secreted the highest amount of IAA, which reached 9.87 mg/L. MP6 had the greatest ability to solubilize inorganic phosphorus, with a solubilization rate of 1 470.69 μg/mL, while K85 showed the best performance in solubilizing organic phosphorus, with a solubilization rate of 1 321.23 μg/mL. MP41 excelled in potassium solubilization, with a solubilization rate of 140.33 mg/L. Ultimately, 14 bacterial consortia were constructed, in which T2 exhibited the best synthetic performance, with a nitrogen-fixing rate of 0.212 g/L, a potassium solubilization rate of 86.28 mg/L, and an IAA secretion rate of 16.91 mg/L. Moreover, its inhibition rates against the 6 pathogenic fungi all reached over 60.00%, and even 87.69% against F. equiseti. Strains LB17, K87, and MP6 in this consortium were all identified as Bacillus velezensis. T2 demonstrated significant biocontrol efficacy against root rot in naked barley, with the control effects exceeding 70.00%, and exhibited remarkable plant growth-promoting properties. [Conclusion] This study developed an efficient bacterial consortium for the management of crop root rot and the promotion of crop growth in the unique agro-ecosystems in Gansu and Qinghai Provinces.

[Objective] Waste printed circuit boards (PCBs) contain about 40% non-ferrous metals, which is more than 40 times that of natural ores, and thus they are known as a veritable “urban mine”. To achieve efficient and green recycling of PCBs, this study developed a leaching system that can efficiently leach non-ferrous metals from PCBs. [Methods] Acidithiobacillus ferrooxidans MA-Y1 was used to construct a bioleaching system for PCBs. Additionally, an electric current was introduced to strengthen the Cu and Ni leaching from PCBs. [Results] The optimal leaching parameters were addition of PCBs at 80.0 g/L, particle size of 4.0 cm, liquid velocity of 2.0 L/min, and electric current of 70.0 mA. Under these conditions, the leaching ratios of Cu and Ni from PCBs were 84.0% and 75.3%, respectively, which represented increases of 15.8% and 17.1% compared with the case without electric current. [Conclusion] An electric current improves the ability of A. ferrooxidans MA-Y1 to recover Cu and Ni from PCBs.