Synthetic and Systems Biotechnology最新文献

{"title":"Engineered bacteriophage-based bioimaging Technology: Development and applications","authors":"Yuanzhao Shen ,&nbsp;Lichang Sun ,&nbsp;Jun Li ,&nbsp;Xin Zhou ,&nbsp;Ran Wang","doi":"10.1016/j.synbio.2025.07.009","DOIUrl":"10.1016/j.synbio.2025.07.009","url":null,"abstract":"<div><div>Engineered bacteriophages (phages) have emerged as powerful and versatile tools for bioimaging, owing to their natural specificity for bacterial targets and their amenability to functional modification. This review summarizes recent advances in the development and application of phage-based imaging probes, with a particular focus on surface functionalization techniques and genetic engineering strategies used to construct functional phage imaging agents. These engineered phage probes have been applied across diverse imaging modalities, including fluorescence, magnetic resonance imaging (MRI), nuclear imaging, near-infrared (NIR) optical imaging, and surface-enhanced Raman scattering (SERS), etc. and have been utilized to enable highly sensitive detection of bacterial pathogens, improved diagnosis of infectious diseases, and monitoring of tissue engineering processes. Despite these innovations, critical challenges remain in ensuring robust target specificity, precise control of labeling stoichiometry, and favorable biocompatibility. Addressing issues such as non-specific probe binding, signal quenching, and immunogenicity will be crucial to fully realize the potential of phage-based bioimaging. Looking ahead, this review discusses future directions for next-generation phage imaging platforms with enhanced specificity, multiplexed functionality, and improved translational potential for clinical diagnostics.</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1352-1367"},"PeriodicalIF":4.4,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineering non-P450 3-hydroxylase for de novo synthesizes catechol-containing compounds in Escherichia coli","authors":"Xing-Run Zheng,&nbsp;Guan-Peng Li,&nbsp;Qian-Hui Chen,&nbsp;Jian-Zhong Liu","doi":"10.1016/j.synbio.2025.07.014","DOIUrl":"10.1016/j.synbio.2025.07.014","url":null,"abstract":"<div><div>Catechols (such as <span>l</span>-DOPA, caffeic acid and hydroxytyrosol, etc.) are a class of phenolic derivatives with ortho-hydroxyl groups which represents various bioactivities including antioxidative, anti-inflammatory, antiviral, and anticancer properties. Non-P450-dependent 3′-hydroxylases HpaBC are the rate-limiting enzymes in catechol biosynthesis. Herein, different HpaB/HpaC combinations were first investigated. The best combinations of KpHpaB from <em>Klebsiella pneumoniae</em> and PaHpaC from <em>Pseudomonas aeruginosa</em> (or SeHpaC from <em>Salmonella enterica</em>) were obtained for the <em>de novo</em> synthesis of <span>l</span>-DOPA in <em>E. coli</em>, resulting in 1838.56 mg/L <span>l</span>-DOPA (or 1822.99 mg/L <span>l</span>-DOPA). The highest production of caffeic acid and hydroxytyrosol were obtained with the enzyme combinations of PaHpaB from <em>P. aeruginosa</em> and SeHpaC from <em>S</em>. <em>enterica,</em> and PlHpaB from <em>Photorhabdus luminescens</em> and KpHpaC from <em>K. pneumoniae</em>, respectively. Next, PaHpaB and PlHpaB were further engineered to improve their catalytic efficiency by the semi-rational method. PaHpaB^A211W and PlHpaB^S210G were obtained. The titer of caffeic acid was further increased to 1281.25 mg/L without <span>l</span>-DOPA accumulation using the PaHpaB^A211W-UTR-SeHpaC hybrid. The production of hydroxytyrosol was further enhanced to 1681.42 mg/L using the combination of PlHpaB^S210G-UTR- KpHpaC. The production of <span>l</span>-DOPA, caffeic acid and hydroxytyrosol was increased using these hybrids of HpaB/HpaC by 4.6-fold, 10.1-fold, and 8.4-fold compared to EcHpaBC from <em>Escherichia coli</em>, respectively. This work demonstrates that pairing of HpaB/HpaC and engineering HpaB is an powerful method for improving 3-hydroxylase activity and the production of catechol-containing compounds.</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1294-1305"},"PeriodicalIF":4.4,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineered membraneless organelles in Corynebacterium glutamicum for enhanced indigoidine biosynthesis and antimicrobial peptide production","authors":"Manman Sun ,&nbsp;Yimeng Zhao ,&nbsp;Rodrigo Ledesma-Amaro ,&nbsp;Jin Gao ,&nbsp;Xiuxia Liu ,&nbsp;Zhonghu Bai ,&nbsp;Alex Xiong Gao ,&nbsp;Peng Wang","doi":"10.1016/j.synbio.2025.08.001","DOIUrl":"10.1016/j.synbio.2025.08.001","url":null,"abstract":"<div><div>Liquid-liquid phase separation (LLPS)-driven membraneless organelles (MLOs) have been employed to enhance metabolic efficiency in various microbial cell factories. However, their application in the industrial bacterium <em>Corynebacterium glutamicum</em> has not been explored. Here, we report the formation of liquid protein condensates in <em>C. glutamicum</em> using the RGG domain of <em>Caenorhabditis elegans</em> LAF-1. We optimized conditions for condensate formation, including the pre-induction period, inducer concentration, and cultivation temperature. Using the indigoidine biosynthesis pathway as a model, we demonstrated that LLPS-mediated MLOs enhanced indigoidine production. Furthermore, we applied these MLOs to modulate the toxicity of antimicrobial peptides (AMPs) to host cells, facilitating the expression of AMPs, including melittin and lactoferricin B. These findings provide insights into MLOs engineering in <em>C. glutamicum</em> and suggest broader applications of LLPS-mediated systems in industrial biotechnology.</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1331-1340"},"PeriodicalIF":4.4,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated protein and metabolic engineering enable high-yield biosynthesis of resveratrol derivatives in Yarrowia lipolytica","authors":"Yuanqing Wu,&nbsp;Shuifeng Zheng,&nbsp;Zhibin Yang,&nbsp;Xiaodong Zhang,&nbsp;Rusong Li,&nbsp;Aitao Li","doi":"10.1016/j.synbio.2025.07.010","DOIUrl":"10.1016/j.synbio.2025.07.010","url":null,"abstract":"<div><div>Piceatannol and pterostilbene, two resveratrol derivatives with superior pharmacological properties, hold significant promise for therapeutic and nutraceutical applications. Despite significant progress in their biosynthesis from resveratrol, microbial <em>de novo</em> biosynthesis of these compounds remains underexplored. Here, we engineered <em>Yarrowia lipolytica</em> to achieve <em>de novo</em> production of piceatannol and pterostilbene from glucose via integrated protein and metabolic engineering. First, a high-yielding resveratrol-producing <em>Y</em>. <em>lipolytica</em> strain was constructed by optimizing heterologous pathway and overexpressing key enzyme, achieving 526.0 mg/L resveratrol. Then, the introduction of HpaBC monooxygenase from <em>Pseudomonas aeruginosa</em> produced 273.1 mg/L piceatannol, while expression of caffeic acid <em>O</em>-methyltransferase (COMT) from <em>Arabidopsis thaliana</em> yielded 61.8 mg/L pterostilbene. Subsequently, the piceatannol production increased by 25.3 % (342.1 mg/L) through <em>HpaBC</em> genes duplication and cofactor optimization. On the other hand, directed evolution of COMT generated a superior mutant (H164Q/T308N/V311I/A160V/H321L/N322F), which was combined with multi-copy chromosomal integration, increased the production of pterostilbene by 190.3 % to 179.4 mg/L. Overall, this work establishes an efficient <em>de novo</em> biosynthesis platform for piceatannol and pterostilbene in <em>Y. lipolytica</em>, delivering the highest microbial titers reported to date and demonstrating the potential of this yeast for scalable production of bioactive stilbenes.</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1368-1376"},"PeriodicalIF":4.4,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in adaptive laboratory evolution applications for Escherichia coli","authors":"Weixiang Peng ,&nbsp;Xi Zhang ,&nbsp;Qingsheng Qi,&nbsp;Quanfeng Liang","doi":"10.1016/j.synbio.2025.07.011","DOIUrl":"10.1016/j.synbio.2025.07.011","url":null,"abstract":"<div><div>Adaptive Laboratory Evolution (ALE), a well-established framework in microbial evolution research, is widely applied in synthetic biology. By simulating natural selection through controlled serial culturing, ALE promotes the accumulation of beneficial mutations, leading to the emergence of specific adaptive phenotypes and bypassing the complexities inherent in rational genetic engineering. With advancements in next-generation sequencing and molecular biology, the integration of high-throughput omics and molecular tools with ALE has significantly enhanced the mapping of genotype-phenotype relationships and the characterization of mutational landscapes. This has propelled progress in microbial evolution, biochemical theory, and interdisciplinary applications. <em>Escherichia coli</em> (<em>E. coli</em>), a premier chassis in synthetic biology, benefits from its genetic tractability and metabolic flexibility, making it an ideal model for ALE studies. This review examines recent developments in ALE applications for <em>E. coli</em>, exploring its methodological principles, experimental design paradigms, notable case studies, and synergies with emerging technologies, providing valuable theoretical insights and practical guidance for related research.</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1306-1321"},"PeriodicalIF":4.4,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Construction of microbial systems for polyethylene terephthalate degradation","authors":"Dingkun He ,&nbsp;Yichen Gong ,&nbsp;Mingzhu Ding ,&nbsp;Yingjin Yuan","doi":"10.1016/j.synbio.2025.07.013","DOIUrl":"10.1016/j.synbio.2025.07.013","url":null,"abstract":"<div><div>Polyethylene terephthalate (PET) is one of the most widely used plastic materials, and its large-scale application has caused severe environmental pollution. Compared to traditional physical and chemical degradation methods, biological degradation is considered the most promising approach. In this context, this review starts with the current research status of PET plastic microbial degradation. Then, it summarizes the construction of strains for heterologous expression of PET-degrading enzymes, the development status of whole-cell catalysts, the innovative ideas of microbial consortia and microorganism-enzyme systems, and the application development of microorganism-functional material systems. In addition, this review includes the use of multiple characterization methods to monitor the degradation effects of PET and changes in strain characteristics, providing theoretical evidence for PET degradation research. Finally, the researches on valorization of PET degradation monomers through synthetic biology are discussed, underscoring the potential of microbial degradation in PET waste upcycling.</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1341-1351"},"PeriodicalIF":4.4,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decoupled tricarboxylic acid cycle and glycolysis of Corynebacterium glutamicum combined with acetate supply promote high-yield biosynthesis of l-homoserine","authors":"Daobin Wang,&nbsp;Lu Xu,&nbsp;Junwen Yuan,&nbsp;Ruisi Wu,&nbsp;Xiyao Cheng,&nbsp;Jidong Liu,&nbsp;Ning Li","doi":"10.1016/j.synbio.2025.07.012","DOIUrl":"10.1016/j.synbio.2025.07.012","url":null,"abstract":"<div><div><span>l</span>-Homoserine is a valuable intermediate with broad applications in the food, pharmaceutical, and chemical industries. Although <em>Corynebacterium glutamicum</em> has been engineered for the efficient biosynthesis of <span>l</span>-homoserine, both production efficiency and glucose conversion remain suboptimal. In this study, an engineered <em>C. glutamicum</em> strain capable of high-yield <span>l</span>-homoserine production from glucose was successfully developed. First, an engineered <em>C. glutamicum</em> strain capable of biosynthesizing <span>l</span>-homoserine using glucose as the sole carbon source was constructed with a yield of 0.38 g/g. To further enhance conversion efficiency, the expression of key genes in the tricarboxylic acid (TCA) cycle was repressed. Among the strategies evaluated, deletion of the <em>aceE</em> gene proved most effective in decoupling glycolysis from the TCA cycle, and acetate supplementation successfully restored cell growth in the decoupled strain. Subsequent metabolic rewiring, including modulation of acetylation efficiency, enhancement of the glyoxylate cycle, and promotion of fumarate-to-<span>l</span>-aspartate conversion, led to substantial <span>l</span>-homoserine accumulation. The engineered strain ultimately achieved an <span>l</span>-homoserine titer of 17.35 g/L with a yield of 0.56 g/g glucose, representing a 48 % increase. Finally, fed-batch fermentation was performed in a 5-L bioreactor using glucose and acetate as mixed carbon sources. The optimized strain, ACg23-6, produced 70.54 g/L <span>l</span>-homoserine within 96 h, with a yield of 0.58 g/g glucose and a productivity of 0.73 g/L/h, while consuming 80 g/L acetate. This decoupling strategy provided valuable insights for improving glucose conversion efficiency and acetate utilization in the microbial production of <span>l</span>-aspartate-derived compounds.</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1322-1330"},"PeriodicalIF":4.4,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning-assisted rational design and evolution of novel signal peptides in Yarrowia lipolytica","authors":"Zizhao Wu ,&nbsp;Wenhao Chen ,&nbsp;Yuxiang Hong ,&nbsp;Yongkai Wang ,&nbsp;Peng Xu","doi":"10.1016/j.synbio.2025.07.008","DOIUrl":"10.1016/j.synbio.2025.07.008","url":null,"abstract":"<div><div>Microbial proteins hold great promise as sustainable alternatives for future protein sources, and oleaginous yeast <em>Yarrowia lipolytica</em> has emerged as a recognized platform for heterologous protein expression and secretion. N-terminal signal peptides (SPs) are crucial for directing proteins to the secretion pathway, which offers advantages in both academic and industrial protein production. Although some of the innate SPs of <em>Y</em>. <em>lipolytica</em> have been reported, there is a growing need to expand the genetic toolkit of SPs to support the increasing use of <em>Y. lipolytica</em> as a cell factory for overproduction of various secretory proteins. In this study, we employed an efficient evolutionary approach to rapidly evolve the innate SP <em>XPR2</em>-pre by leveraging Gibson assembly with two synthetic overlapping oligos containing high portion of degenerate nucleotides. Using Nanoluc (<em>Nluc</em>) luciferase as a robust reporter, we characterized the intracellular and extracellular enzymatic activity of 447 SP mutants and identified previously undescribed SPs exhibiting superior performance compared to <em>XPR2</em>-pre in <em>Nluc</em> luciferase secretion, with improvements of up to 2.91-fold of enzymatic activity in the supernatant. The generalizability of the top-performing SPs was evaluated using three additional heterologous enzymes (β-galactosidase, α-amylase, and PET hydrolase). Our results confirmed their versatility across different proteins with protein-specific efficiency. Additionally, based on our screening, we also evaluated the performance of different feature engineering strategies and machine learning models in the design and prediction of SP mutants. This study integrated rational design, directed evolution and machine learning to identify novel SPs, expanding the repertoire of signal peptides and benefiting secretory protein overexpression in <em>Y</em>. <em>lipolytica</em>.</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1275-1283"},"PeriodicalIF":4.4,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144781009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gene Surfing: An efficient and versatile tool for targeted enzyme mining in metagenomics","authors":"Tong Xu ,&nbsp;Danyang Huang ,&nbsp;Tingting Huang ,&nbsp;Yuxin Wang ,&nbsp;Wanqiu Chen ,&nbsp;Shijunyin Chen ,&nbsp;Yurong Qian ,&nbsp;Haitao Yue","doi":"10.1016/j.synbio.2025.07.006","DOIUrl":"10.1016/j.synbio.2025.07.006","url":null,"abstract":"<div><div>Microbial community studies have established enzymes' pivotal catalytic roles in ecosystem metabolism, yet cultivation-dependent methods fail to exploit uncultured microbial enzyme resources. Metagenomics overcomes this by directly accessing microbial genetic information, but its massive data generation challenges precise enzyme identification: (1) Restricted applicability across varied sample types. (2) Narrow functional scope in target enzyme discovery.</div><div>To address this, we developed Gene Surfing, a bioinformatics workflow platform based on Snakemake. It integrates modules for data quality control (Fastp), genome assembly (MEGAHIT), assembly evaluation (QUAST and MetaQUAST), functional annotation (Prokka), and homologous sequence retrieval (MMseqs2). Gene Surfing offers scalability, reproducibility, and efficiency, addressing key challenges in enzyme identification. Validation results include: Cellulose-degrading enzymes (GH5 family): 1,311,316 potential lignocellulolytic enzyme sequences were identified, with 127 sequences functionally validated (84.25 % activity rate); Polyethylene-degrading enzymes: 705 candidate sequences were found, 38 of which were heterologously expressed, showing an 81.5 % activity rate (31/38); Endonucleases (HNH superfamily): 585 potential sequences were retrieved, with 4 out of 7 tested showing activity (57.1 % success rate).</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1377-1387"},"PeriodicalIF":4.4,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144880236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decoding metabolic trade-offs in Halomonas elongata: Chemostat-based flux remodeling for industrial ectoine biosynthesis","authors":"Junxiong Yu,&nbsp;Hao Liu,&nbsp;Yudi Wang,&nbsp;Runlin Ju,&nbsp;Yue Zhang,&nbsp;Ali Moshin,&nbsp;Yingping Zhuang,&nbsp;Meijin Guo,&nbsp;Zejian Wang","doi":"10.1016/j.synbio.2025.07.004","DOIUrl":"10.1016/j.synbio.2025.07.004","url":null,"abstract":"<div><div><em>Halomonas elongata</em>, a moderately halophilic γ-proteobacterium of industrial interest, serves as a microbial cell factory for ectoine—a high-value compatible solute extensively utilized in biopharmaceuticals and cosmetics. While its ectoine biosynthesis potential is well-documented, the systemic metabolic adaptations underlying osmoadaptation remain poorly characterized, limiting rational engineering strategies for optimized production. To address this gap, we employed chemostat cultivation coupled with multi-omics integration (physiological profiling, metabolomics, and metabolic flux analysis) to dissect salt-dependent metabolic network rewiring in the model strain DSM 2581^T under moderate (6.0 % NaCl) and high salinity (13.0 % NaCl)<em>.</em> Results demonstrated that, under moderate salt conditions, a specific growth rate (<em>μ</em>) of 0.20 h⁻¹ significantly enhanced the ectoine-specific production rate (<em>q</em>_p), intracellular ectoine content (<em>p</em>_ectoine), and yield coefficient (<em>Y</em>_p/s), concurrent with redirection of carbon flux toward the Entner-Doudoroff (ED) pathway and ectoine biosynthesis. Under high salt conditions, flux through both the ED pathway and ectoine biosynthesis was further upregulated, whereas fluxes through the pentose phosphate (PP) pathway, tricarboxylic acid (TCA) cycle, and CO₂ generation were downregulated. Simultaneously, suppression of the flux from malate to pyruvate enhanced oxaloacetate synthesis, thereby increasing the supply of key precursors including glutamate, aspartate, and NADPH to fuel ectoine biosynthesis. Stepwise salt reduction experiments revealed bidirectional metabolic flexibility: elevated salinity prioritized carbon investment into ED-driven ectoine production, whereas hypo-osmotic conditions reactivate respiratory activity and the TCA cycle to fuel energy metabolism. These findings establish <em>H. elongata</em> as a paradigm of dynamic flux rewiring, where carbon economy is strategically reallocated between stress-protective solute biosynthesis and energy homeostasis. This study bridges the knowledge gap in understanding the physiological characteristics of <em>H. elongata</em> and provides a foundation for improving ectoine production and engineering strains through metabolic optimization.</div></div>","PeriodicalId":22148,"journal":{"name":"Synthetic and Systems Biotechnology","volume":"10 4","pages":"Pages 1242-1256"},"PeriodicalIF":4.4,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}