World journal of microbiology & biotechnology最新文献

Butyric acid, a short-chain organic acid, is extensively used in the chemical, food, and pharmaceutical industries. Given the constraints in raw materials for traditional chemical synthesis and the rising consumer preference for natural products, microbial fermentation has emerged as a promising and sustainable alternative for butyric acid manufacture. This review provides a detailed elaboration of four biosynthetic pathways for microbial butyric acid production. It summarizes recent advances in butyric acid producers, encompassing both natural producers like Clostridium and emerging producers such as Escherichia coli. Their fermentation performance is systematically compared based on key metrics, including yield, tolerance, substrate utilization range, and process maturity. Butyric acid production was improved through targeted metabolic engineering and optimized fermentation processes, working in concert to enhance overall biosynthesis efficiency. Finally, it concludes with a summary and a perspective on future research priorities, which are anticipated to focus on systems metabolic engineering and integrated bioprocess development to enhance economic feasibility.

The phyllosphere, encompassing the aerial surfaces of plants, represents one of the largest microbial habitats on Earth and plays a pivotal yet underutilized role in sustainable agriculture and environmental health. Colonized by diverse bacterial, fungal, and yeast communities, the phyllosphere microbiome significantly influences plant growth, disease resistance, nutrient dynamics, and abiotic stress tolerance. These microorganisms engage in complex interactions with host plants, often functioning as biofertilizers, biopesticides, and stress protectants by producing phytohormones, antimicrobial metabolites, and stress-responsive compounds. Importantly, phyllospheric microbes also contribute to atmospheric and ecological balance by participating in carbon and nitrogen cycling, degrading volatile organic compounds (VOCs), and mitigating air pollution. However, despite their immense potential, the practical application of phyllospheric microbes remains limited by challenges such as environmental instability, poor field persistence, and incomplete functional characterization. The highly variable microclimate of the leaf surface poses survival barriers to both native and introduced microbial inoculants. Moreover, the specificity of plant-microbe associations and the complexity of microbial interactions necessitate precision-based approaches for successful deployment. Recent advances in omics technologies, microbial consortia engineering, and nano-enabled delivery systems provide new opportunities to overcome these limitations. A deeper understanding of phyllosphere microbial ecology, combined with innovations in synthetic biology and ecological modeling, can facilitate the development of robust microbial tools tailored to specific crops and climates. Harnessing the potential of phyllospheric microorganisms is not merely an academic pursuit, it is a strategic imperative for transitioning toward climate-resilient, low-input, and ecologically sound agricultural systems.

Biofilms are surface-attached bacterial consortia, which account for 80% of the world's microbial biomass, and are responsible for 75% of human infections. These surface bacterial communities have enhanced their ability to withstand unfavourable conditions and resist antimicrobial treatments due to the presence of outer membrane proteins (OMPs). Outer membrane proteins (OMPs) play a central role in biofilm formation by mediating adhesion, matrix assembly, and intercellular interactions, and they are increasingly being targeted for novel antibacterial therapies to disrupt biofilm-related infections. OMPs play a crucial role in biofilm formation, as these proteins contribute to the assembly and architecture of the biofilm matrix, interact with other matrix proteins, and influence surface hydrophobicity and cell aggregation. Notably, genetic modifications or deletions of OMPs can increase or decrease biofilm formation, indicating their regulatory influence on matrix composition and biofilm morphology. Incidentally, biofilm poses significant challenges in industry and abiotic medical equipment. OMPs offer excellent targets to mitigate biofilm-forming infections, since blocking their function can reduce bacterial adhesion and disrupt biofilm integrity. Furthermore, antimicrobial peptides as well as nanotechnology-based therapeutics are under development to target OMPs, allowing for innovative approaches that circumvent traditional resistance mechanisms seen in biofilms. This review underscores the significance of key OMPs in devising strategies to combat biofilm-associated infections and offers a concise overview of their structure, function, and immunoprotective role. By targeting outer membrane proteins, emerging therapies seek to address the persistence and antibiotic resistance of biofilm-forming bacteria, representing a promising direction in the treatment of chronic and multidrug-resistant infections.

Abiotic stresses such as salinity, drought, heat, and ultraviolet radiation are among the most serious constraints on global crop productivity. These stresses disrupt photosynthesis, nutrient uptake, and cellular redox balance, leading to major agricultural losses under changing climatic conditions. Members of the genus Streptomyces, long recognized for their exceptional capacity to produce secondary metabolites, have recently emerged as promising bioresources for enhancing plant tolerance to such stresses. Their metabolites include polyketides, phenazines, melanin-like pigments, siderophores, volatile organic compounds, and phytohormone analogs. Collectively, these compounds can improve plant performance by scavenging reactive oxygen species, supporting osmotic adjustment and ion regulation, and modulating hormonal signaling and root architecture. This review summarizes recent progress in understanding how Streptomyces-derived metabolites contribute to abiotic stress alleviation in plants, with emphasis on molecular mechanisms and rhizosphere ecology. Genomics and metabolomics studies further reveal extensive biosynthetic gene clusters with untapped potential for novel bioactive compounds. Evidence from major crops shows improved growth, antioxidant activity, and stress recovery following Streptomyces inoculation or metabolite application. However, key challenges remain, including linking specific metabolites to defined plant responses, standardizing assays, ensuring safety, and scaling production for field use. Integrating multi-omics, co-culture strategies, and formulation technologies will be essential to translate experimental findings into sustainable agricultural practice. Overall, Streptomyces secondary metabolites represent a promising frontier for environmentally sound solutions to abiotic stress in crops.

Paraben contamination has emerged as a significant environmental concern, prompting interest in microbial remediation as a sustainable and eco-friendly solution. This study investigates the biodegradation of benzylparaben (BeP) using three bacterial isolates: Serratia surfactantfaciens, Serratia nematodiphila, and Paenibacillus lautus. Biochemical profiling and 16 S rRNA gene sequencing confirmed their identities, showing 99% sequence similarity with known strains. All isolates tolerated high BeP concentrations (up to 800 mg/L) and exhibited notable degradation kinetics. High-performance liquid chromatography (HPLC) revealed a progressive decline in BeP levels, with S. surfactantfaciens achieving 99% degradation and S. nematodiphila reaching complete degradation within 120 h. P. lautus demonstrated superior efficiency, fully (~ 99%) degrading BeP in just 96 h. Fourier-transform infrared spectroscopy (FTIR) and high-resolution mass spectrometry (HRMS) confirmed structural transformation of BeP and the formation of intermediate metabolites. FTIR spectra lacked characteristic ester and carbonyl peaks in treated samples, indicating compound breakdown. Kinetic modelling revealed a fractional-order degradation pathway (n = 1.5 for Isolate_1; n = 0.5 for Isolates_2 and Isolate_3), suggesting a multi-step enzymatic mechanism. Statistical analysis validated the significant reduction of BeP levels by all isolates compared to controls. These findings underscore the potential of these bacterial strains for effective biodegradation of paraben-contaminated environments and support their application in sustainable wastewater treatment strategies.

Pantoea is a genus of Gram-negative bacteria isolated from diverse environments. Over time, it has drawn considerable attention for its potential to promote plant growth. However, its biotechnological application is complicated by high genomic plasticity, which underlies both its beneficial traits and its ability to cause disease in a wide range of plants, as well as occasional opportunistic infections in humans, raising biosafety concerns. In this study, we conducted a comparative genomic analysis of all publicly available Pantoea genomes. Our goals were to refine taxonomic classifications and to identify genes linked to biotechnological potential, virulence, and antibiotic resistance, thereby clarifying lifestyle strategies within the genus. We found that plant growth-promoting genes are widely conserved, particularly those involved in phosphate solubilization, phytohormone biosynthesis, and siderophore production. In contrast, traits such as nitrogen fixation and ACC deaminase activity were restricted to specific species. The resistome analysis revealed intrinsic resistance mechanisms conserved across the genus, primarily involving diverse efflux pump families and β-lactamases conferring resistance to cephalosporins. In parallel, the pan-GWAS highlighted lifestyle-defining genetic markers, including the hrp/hrc genes encoding type III secretion system components, pepM (phosphoenolpyruvate mutase) associated with the production of a phytotoxin, and ibeB, an invasin linked to clinical infections. Together, our findings underscore both the biotechnological potential of Pantoea and the importance of genetic markers for distinguishing beneficial from pathogenic lifestyles, supporting the safe application of selected strains in biotechnology.

Salmonella spp. are the most important foodborne and zoonotic bacteria in the world, with severe implications for public health, food safety, and the economy. Antimicrobial peptides (AMPs) targeting the innate immune system and new therapeutic targets for conventional antibiotics are largely mediated through electrostatic adsorption onto microbial surfaces with membrane disruption or intracellular interference. However, Salmonella has also evolved complex mechanisms of resistance to reduce the effectiveness of AMPs, among which attachment to surfaces and lipopolysaccharide (LPS) modifications are among the main factors. This review addresses the molecular and structural basis of AMP recognition by the outer membrane of Salmonella focusing on binding involving anionic LPS and how peptide chemistry affects antimicrobial activity. The position of the LPS remodelling reactions is controlled by PhoP, PhoQ, PmrA, and PmrB two component sensor responders, which modify lipid A by adding amino arabinose and other substituents that reduce the negative charge, modify hydrophobicity, and lower AMP binding affinity. Other resistance mechanisms, including efflux systems, proteolytic degradation, and biofilm formation, have been studied in terms of binding evasion. In addition to mechanistic insights, this review also discusses the clinical and health implications of AMP resistance, considering zoonotic transmission, agricultural pressure, and cross-resistance to polymyxins. New therapeutic strategies include engineered AMPs with enhanced binding affinities, nano-delivery platforms, and synergistic combinations of AMPs with antibiotics. This review concludes by underlining the value of continued investigation of Salmonella surface binding and remodelling as critical drivers of AMP resistance and drug discovery.

Sophorolipid (SL) are glycolipid biosurfactants with growing industrial relevance as sustainable alternatives to petrochemical surfactants. This review highlights the advances in SL genetics and pathway architecture, transcriptional and process level regulation, and comparative performance of native producers versus recombinant platforms. It emphasizes the transition from empirical optimization to rational, systems guided strategies integrating advance metabolic engineering strategies including pathway optimization to divert carbon flux toward the SL module, balance redox/energy demands with growth, and tailor congener profiles. We further evaluated the current industrial feasibility, technology used by several companies highlighting progress increasing titers and productivities alongside persistent constraints in production, reliance on costly feedstocks, different fermentation methods, process parameters, and challenging downstream recovery. Key research gaps include incomplete understanding of regulatory control, limited systematic flux redistribution, and insufficient techno-economic integration. We outline future priorities for CRISPR enabled and omics guided rewiring, secretion and tolerance engineering, deployment of low cost/waste substrates, and standardized, scalable purification. These directions define a roadmap to robust, cost competitive SL manufacturing and clarify where recombinant hosts can complement or extend capabilities beyond Starmerella bombicola.

Here, ACC deaminase ACC Deaminase producing rhizobacteria, Priestia aryabhattai MD-85 (Accession no. PV155249.1) and Enterobacter cloacae MD-79 (Accession no. PV155250.1), were assessed for their potential to enhance water-deficit stress tolerance in muskmelon. Both strains produced ACC Deaminase and exhibited drought tolerance, with MD-79 showing 78.9 ± 7.6 µM α-ketobutyrate mg⁻¹ protein h⁻¹ at 18%-PEG, and MD-85 showing 68.4 ± 5.4 µM α-ketobutyrate mg⁻¹ protein h⁻¹ at 21%-PEG. Both strains produced multi-functional growth-promoting substances under PEG-induced stress, conferring their significant drought tolerance potential. Increasing water stress negatively impacted growth and physiological characteristics of soil-grown muskmelon plants. However, ACC Deaminase-producing strains, especially when applied in combination (P. aryabhattai MD-85 + E. cloacae MD-79), effectively mitigated adverse effects of drought stress. For instance, under 3%-polyethylene glycol (PEG)-induced stress in muskmelon, co-inoculation (MD-79 + MD-85) enhanced root length (44.3%), shoot length (47.6%), root dry and fresh wight ratio (40.7%), leaf dry and fresh wight ratios (51.7%), total chlorophyll (41.5%), and carotenoids (38.8%). Further, bacterial consortia significantly (p ≤ 0.05) enhanced chlorophyll colour index (56.7%), net photosynthetic rate (64.3%), Fv/Fm (50.8%), stomatal conductance (64.3%) and relative water content (62.3%) in leaf tissues of 3%-PEG-stressed muskmelon. Single/combined bacterial inoculation lowered drought-induced oxidative stress markers in muskmelon. Moreover, bacterial partners strengthened antioxidant enzymes in water-deficit affected muskmelon. The 15%-PEG + MD-79 + MD-85 treatment exhibited greater increase in catalase (79.3%), ascorbate peroxidase (65.3%), peroxidase (55.7%), and superoxide dismutase (72%), activities over their respective untreated controls. Additionally, bacterial strains modulated ion homeostasis in PEG-stressed muskmelon roots, enhancing drought tolerance. Notably, combined inoculation synergistically enhanced drought tolerance compared to single-strain treatments. This study emphasizes the potential of ACC Deaminase-producing PGPR as a sustainable and long-term strategy to improve muskmelon resilience under water-deficit condition by modulating physiological, biochemical, and ionic responses. These findings underscore the use of PGPR in drought management to enhance crop productivity and stress tolerance.