Shiyu Wei

( S )‐2‐Amino‐1‐butanol, a key intermediate for ethambutol hydrochloride synthesis, is currently produced via heavy metal‐catalyzed processes or enzymatic resolution with limited theoretical yields. While amine dehydrogenases (AmDHs) offer sustainable alternatives for asymmetric reductive amination, their applicability is often restricted by narrow substrate scope. Here, we report the discovery of a thermostable amino acid dehydrogenase from Thermoactinomyces daqus ( Td AADH) that exhibits optimal activity at pH 9.0 and 55 °C with exceptional thermostability ( t _1/2 = 21 days at 40 °C). Although inactive toward the non‐native substrate 1‐hydroxy‐2‐butanone, structure‐guided engineering via site‐directed and iterative saturation mutagenesis (ISM) successfully endowed the enzyme with desired functionality: the initial double mutant K93S/N288L (M1) acquired de novo amination activity, while subsequent evolution to the quintuple mutant M4 (incorporating L136T/T139D/M141R) enhanced specific activity by 2.75‐fold (5.38 U·g ⁻¹ ) without compromising enantioselectivity ( ee > 99%). Mechanistic investigations via molecular docking suggest that these mutations plausibly reshape the substrate‐binding pocket, alleviate steric hindrance, and optimize electrostatic interactions to accommodate the hydroxyketone substrate. Preparative‐scale biotransformation (40 °C, 30 mM substrate, coupled with GDH/glucose for cofactor recycling) achieved quantitative conversion (≥99%) within 36 h. This work expands the enzymatic toolbox for thermostable AmDHs.

Potato (Solanum tuberosum L.) starch is valued for its large granules, high paste viscosity, and neutral taste, yet its gelatinized form is rapidly digested and its native granules resist enzymatic attack. This review synthesizes peer-reviewed studies indexed in Scopus, Web of Science, PubMed, Crossref, and Google Scholar from January 2000 to September 2026, with emphasis on 2018 onward, classifying evidence as direct (potato starch as substrate) or extrapolated (other starch systems). Hydrolases depolymerize potato starch, generate porous granules, or supply linear chains for type 3 resistant starch, whereas 4-α-glucanotransferases, branching enzymes, amylosucrase, and cyclodextrin glucanotransferases deplete amylose, elongate exterior chains, introduce α-1,6 linkages, or produce cyclic glucans. The strongest direct evidence supports thermoreversible gels, pullulanase-assisted resistant starch, slowly digestible starch, low-digestibility starch, cyclodextrin production, and acid-assisted porous starch. Ultrasound, high hydrostatic pressure, irradiation, and hydrothermal treatments modulate enzyme accessibility but remain strongly condition-dependent. Translation is constrained by gelatinization and drying energy, reaction viscosity, enzyme cost and recovery, and heterogeneous digestibility assays. Priority actions include raw-granule-active enzymes, standardized potato-starch assays, rational enzyme cascades, structure-guided enzyme engineering, and product-specific human and life-cycle assessments.

Amine dehydrogenases (AmDHs) are efficient biocatalysts for asymmetric chiral amine synthesis. This study reports the mining and systematic characterization of three thermophilic amino acid dehydrogenases (AADHs): TmAADH, TaAADH, and MtAADH. Phylogenetically, these enzymes occupy an intermediate position between leucine and phenylalanine dehydrogenases, suggesting hybrid active-site architectures. They shared an optimal pH of 9.0 for reductive amination but differed in oxidative deamination (pH 10.5–11.0) and thermal profiles (optima 35–45 °C; stability hierarchy TmAADH > TaAADH > MtAADH). While all preferred the reductive direction (25–340-fold activity enhancement), they exhibited complementary substrate specificities: MtAADH favored branched aliphatic keto acids, TaAADH short-chain substrates, and TmAADH aromatic α-keto acids. Rational engineering of conserved carboxyl-binding sites (MtAmDH(K67S/N261L), TaAmDH(K68S/N261L) and TmAmDH (K69S/N264L)) successfully converted these AADHs into AmDHs, conferring de novo catalytic activity toward prochiral hydroxy ketones with excellent enantioselectivity (>90% ee, S-configuration). These robust biocatalysts offer promising enzymatic tools for industrial chiral amine production.

Acetamiprid (ACE) and thiacloprid (THIA) are the dominant cyano-substituted neonicotinoids detected in fruit juices and bottled water, which raises food-safety concerns and regulatory scrutiny. Conventional purification with activated carbon or advanced oxidation shows limited selectivity and has a high energy demand. Covalent organic frameworks (COFs) offer tunable chemistry for targeted adsorption, yet no strategy exists to engineer COF sites that preferentially recognize the cyano group of ACE/THIA. Here, we synthesized a magnetic core-shell adsorbent, Fe₃O₄@COF(TBTD-BD)-Au, by growing cyano-affinitive Au nanoparticles on a Cl-decorated COF shell surrounding a Fe₃O₄ core. Under optimized conditions (pH 6.0, 25 °C), the Fe₃O₄@COF(TBTD-BD)-Au achieved maximum adsorption capacities of 157 mg g⁻¹ (ACE) and 156 mg g⁻¹ (THIA). Uptake followed pseudo-second-order kinetics and the Freundlich isotherm; thermodynamic analysis confirmed an endothermic, spontaneous process. Competitive tests showed >80% removal of ACE and THIA in the presence of four co-occurring neonicotinoids, and the adsorbent retained 91.5% of its initial capacity after six adsorption–desorption cycles. Synergistic Au-cyano coordination, Cl-mediated hydrogen bonding, and π–π stacking confinement confer high selectivity and capacity. This ligand-guided, post-functionalized COF provides promising potential in the field of food sample treatment for contaminant removal.

Fusarium avenaceum is the predominant fungal pathogen responsible for root rot in Angelica crops and poses a serious threat to their commercial quality and yield in China. This fungus produces enniatin B (ENN B), a toxin that could be a pathogenicity and virulence factor in plant–pathogen interactions. Yet whether ENN B exacerbates host infection and the onset of root rot in Angelica spp. caused by F. avenaceum is surprisingly understudied. Pathogenicity assays revealed that ENN B co-inoculation with F. avenaceum significantly increased the root rot disease index in Angelica sinensis from 83.33% (pathogen alone) to 92.86% (p < 0.05). Toxin degradation experiments showed that the bacteria Paenibacillus polymyxa and Bacillus tequilensis were capable of degrading 60.69% and 70.02% of ENN B, respectively. Response surface optimization (24.5 °C, 22.01 mg/L ENN B, 0.99% inoculum) enhanced degradation by B. tequilensis to 81.94%, a 11.74% improvement. Three ester compounds were identified by LC-HRMS as potential degradation products of ENN B. In planta trials demonstrated that the disease index was 50.01% for the group co-inoculated with ENN B degradation products and F. avenaceum, a 42.85% reduction compared to the group co-inoculated with ENN B and F. avenaceum. This study provides a new microbial strategy for controlling root rot in Angelica crops from a mycotoxin degradation perspective, which can be applied to promote sustainable agricultural production.