Liang Zhang

Biosynthesis of complex natural products in engineered microbial hosts is frequently constrained by unstable oxidation‐prone intermediates that disrupt metabolic balance and lower carbon flux efficiency. In the synthesis pathways of polyphenolic compounds, redox‐sensitive nodes often function as bottlenecks due to intermediate accumulation and spontaneous oxidation under aerobic conditions. In this study, the oxygen‐dependent degradation of L‐3,4‐dihydroxyphenylalanine (L‐DOPA), a redox‐sensitive intermediate in curcumin biosynthesis, was characterized, and a hierarchical strategy was implemented to stabilize oxidation‐prone nodes while rebalancing intracellular carbon and electron fluxes. Adaptive evolution improved host robustness, respiratory chain modulation redistributed reducing equivalents under oxygen limitation, and directed evolution of 4‐hydroxyphenylacetate 3‐monooxygenase (HpaB) rebalanced intermediate distribution and enhanced productive hydroxylation. Combined with multistage pH–DO control, these strategies markedly improved carbon utilization efficiency and curcumin biosynthesis. In 5 L fed‐batch fermentation, curcumin production reached 1075.2 mg/L, the highest reported titer for single‐strain de novo curcumin biosynthesis. Extension of this framework to caffeic acid production increased the titer by approximately 69.1% and reduced A ₄₀₀ ‐associated browning, supporting transferability to another oxidation‐prone phenolic product. This study demonstrates the effectiveness of flux protection in curcumin biosynthesis and supports the potential transferability of this framework to related HpaB‐dependent phenylpropanoid pathways.

Capsanthin is a high‐value tetraterpenoid widely utilized in the food, cosmetic, and pharmaceutical industries. However, its traditional production via plant extraction and chemical synthesis faces severe sustainability and cost constraints. The oleaginous yeast Yarrowia lipolytica ( Y. lipolytica ) offers a superior chassis due to its robust mevalonate pathway and abundant lipid droplets for pigment sequestration. In this study, we systematically engineered Y. lipolytica for the de novo biosynthesis of capsanthin. By heterologously co‐expressing of Capsicum annuum capsanthin/capsorubin synthase (CaCCS) and Arabidopsis thaliana zeaxanthin epoxidase (AtZEP), we achieved the first reported biosynthesis of capsanthin in Y. lipolytica . Combinatorial screening revealed that full‐length sequences of CaCCS and AtZEP yielded optimal production of 6.92 mg/L. To further enhance the productivity of capsanthin, we evaluated spatial compartmentalization strategies. The results demonstrated that targeting the biosynthetic enzymes to the peroxisome via Ser–Lys–Leu (SKL) tags successfully increased the titer to 8.8 mg/L by leveraging its specialized lipophilic and redox microenvironment. Finally, a 5‐L fed‐batch fermentation was conducted, achieving a maximum capsanthin titer of 48.15 mg/L. This work provides a sustainable and scalable alternative to plant extraction and chemical synthesis for capsanthin production.

Background: Spread through air spaces (STAS) is an adverse invasive pattern in lung adenocarcinoma (LUAD), but reliable biomarkers for preoperative or intraoperative prediction remain limited. We investigated whether the intratumoral microbiome and metabolome are associated with STAS. Methods: Fresh tumor and paired adjacent non-tumor lung tissues from resected LUAD were analyzed using 5-region 16S rRNA gene sequencing and untargeted metabolomics. Microbiome–metabolome correlations were assessed by Spearman analysis, and receiver operating characteristic curves were used to evaluate diagnostic performance. The clinical relevance of ABCA3 was further explored using GEPIA2. ABCA3 and MMP9 expression was additionally assessed in selected same-cohort tumor samples by qRT-PCR. Results: Tumor tissues displayed a distinct microbial composition characterized by Corynebacterium enrichment and a metabolomic profile marked by phospholipid remodeling. Corynebacterium abundance was positively correlated with phosphatidylcholine and sphingomyelin species, but negatively correlated with several amino acids. STAS-positive tumors showed higher Corynebacterium abundance and increased membrane-lipid accumulation than STAS-negative tumors. An integrated model combining Corynebacterium, PC(39:6), and SM(d18:1/17:0) showed high apparent discrimination in this exploratory cohort(AUC = 0.98), although external validation is required. In external transcriptomic analyses, higher ABCA3 expression was associated with better overall survival and was inversely correlated with MMP9 expression in LUAD. In selected same-cohort tumor samples, qRT-PCR showed significantly lower ABCA3 expression and higher MMP9 expression in the STAS-positive/Corynebacterium-enriched group than in the STAS-negative/Corynebacterium-low group. Conclusions: Intratumoral Corynebacterium is associated with phospholipid metabolic reprogramming and a STAS-positive phenotype in LUAD. A combined microbial–metabolic signature may aid STAS risk stratification and suggests a potential association with ABCA3-related lipid homeostasis, but causal relationships require functional validation. Same-cohort qRT-PCR further supported an ABCA3-low/MMP9-high invasive expression pattern in the selected STAS-positive/Corynebacterium-enriched samples.

Naphthalene (Nap) is widely distributed in the environment and has attracted concern due to its recalcitrance to biodegradation and acute toxic effects. Although several laccases can degrade naphthalene, it remains unclear whether laccase is involved in dioxygenation or ring fission of polycyclic aromatic hydrocarbons (PAHs). We demonstrated that laccase has a naphthalene dioxygenase function with a distinct joint approach to oxygen and the alternative regioselective ring-fission process. These results supplement the family of dioxygenase with laccase, a mild method for the ring opening of aromatics, and an operable scale-up application for remediation from PAH pollution and for regioselective oxygenation and ring opening.

Sporulation represents a complex metabolic reprogramming process in bacteria. In this study, we used CRISPR-Cpf1 to knock out spoIIE and rsfA in Bacillus licheniformis. The ΔspoIIE strain completely lost sporulataion capacity, while ΔrsfA showed a 25% reduction. Although viable cell counts decreased by 80.7% and 45.7%, respectively, glucose consumption and 2,3-butanediol synthesis remained unchanged, and acetoin synthesis increased by 19% in ΔspoIIE. Per-cell metabolic rates were significantly enhanced: glucose uptake increased 2.7–3.4-fold, acetoin synthesis 2.3–4.2-fold, 2,3-butanediol synthesis 1.7-fold, and heterologous protein expression 10–15-fold. These findings demonstrate that blocking sporulation liberates metabolic resources and enhances the specific productivity of vegetative cells, providing a strategy for engineering high-performance B. licheniformis cell factories.

2'-Fucosyllactose (2'-FL), the most abundant oligosaccharide in human milk, exhibits diverse bioactivities and is added to infant formula to simulate breastfeeding. Herein, Yarrowia lipolytica was employed as a microbial chassis for the de novo biosynthesis of 2'-FL. A complete biosynthetic pathway was established via genomic integration, resulting in an initial titer of 2.16 g/L. Systematic metabolic analysis identified the fucosyltransferase (FutC)-catalyzed reaction as the key rate-limiting step, alleviated by promoter engineering upregulating FutC, enhancing 2'-FL production. Additional strategies, including enhancing GDP-fucose supply, knocking out the PFK gene to redirect carbon flux, and strengthening the pentose phosphate pathway (PPP), further boosted production. Fed-batch fermentation with a mixed carbon source led to a titer of 105.88 g/L and a productivity of 0.98 g/L/h in strain YL16-6, representing the highest reported 2'-FL production in a plasmid- and antibiotic-free microbial system to date. This work demonstrates the potential of Y. lipolytica as a robust, scalable cell factory for the sustainable and antibiotic-free industrial production of 2'-FL.