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Alginate lyase is an attractive biocatalyst that can specifically degrade alginate to produce oligosaccharides, showing great potential for industrial and medicinal applications. Herein, an alginate-degrading strain HB236076 was isolated from Sargassum sp. in Qionghai, Hainan, China. The low 16S rRNA gene sequence identity (<98.4%), ANI value (<71.9%), and dDDH value (<23.9%) clearly indicated that the isolate represented a potential novel species of the genus Vibrio. The genome contained two chromosomes with lengths of 3,007,948 bp and 874,895 bp, respectively, totaling 3,882,843 bp with a G+C content of 46.5%. Among 3482 genes, 3332 protein-coding genes, 116 tRNA, and 34 rRNA sequences were predicted. Analysis of the amino acid sequences showed that the strain encoded 73 carbohydrate-active enzymes (CAZymes), predicting seven PL7 (Alg1–7) and two PL17 family (Alg8, 9) alginate lyases. The extracellular alginate lyase from strain HB236076 showed the maximum activity at 50 °C and pH 7.0, with over 90% activity measured in the range of 30–60 °C and pH 6.0–10.0, exhibiting a wide range of temperature and pH activities. The enzyme also remained at more than 90% of the original activity at a wide pH range (3.0–9.0) and temperature below 50 °C for more than 2 h, demonstrating significant thermal and pH stabilities. Fe2+ had a good promoting effect on the alginate lyase activity at 10 mM, increasing by 3.5 times. Thin layer chromatography (TLC) and electrospray ionization mass spectrometry (ESI-MS) analyses suggested that alginate lyase in fermentation broth could catalyze sodium alginate to produce disaccharides and trisaccharides, which showed antimicrobial activity against Shigella dysenteriae, Aeromonas hydrophila, Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli. This research provided extended insights into the production mechanism of alginate lyase from Vibrio sp. HB236076, which was beneficial for further application in the preparation of pH-stable and thermo-stable alginate lyase and alginate oligosaccharides. [ABSTRACT FROM AUTHOR]

Na2FePO4F, an iron‐based fluorophosphate with facile 2D sodium ion channels, is considered as a promising cathode material for sodium‐ion batteries because of low cost, resource abundance, and nontoxicity. However, its application is considerably restricted by the limited intrinsic electronic conductivity and specific capacity. Herein, a doping strategy represented by Cu2+ is proposed to boost the electrochemical performance, attributed to the derivation of a new active Na3 site originated from the inert Na1 site and the band gap reduction due to the d‐orbital hybridization. Consequently, the as‐obtained Na2Fe0.95Cu0.05PO4F/C composite can deliver an excellent rate capacity of 74 mAh g⁻1 at 20 C and a decent specific capacity of 119 mAh g⁻1 at 0.1 C, which is superior to the previously reported Na2FePO4F‐based cathode materials. This study sheds new light on developing high performance fluorophosphates cathode materials via regulating the Na site and electronic structure. [ABSTRACT FROM AUTHOR]

Stir bar sorptive extraction (SBSE) combined with gas chromatography-olfactory-mass spectrometry (GC-O-MS) was used to identify and describe the key aroma components of three representative oolong tea varieties, Huangdan, Tieguanyin and Jinguanyin. Comparative analysis was conducted in terms of odor activity value (OAV), aroma character impact (ACI) value and sensory evaluation. The sensory evaluation showed that each variety showed obvious aroma characteristics. Huangdan oolong tea had an obvious floral aroma as well as a slight milky aroma. Tieguanyin oolong tea had a strong floral aroma. Jinguanyin oolong tea had a sweet fruity aroma as well as a slight woody aroma. According to the results of OAV and GC-O-MS analysis, geraniol, phytol, methyl jasmonate, trans-nerol tertiary alcohol, 2-nonone, and phenyl ethanol were identified as key aroma components in Huangdan oolong tea, which provided it with clean and high floral aroma and obvious milky aroma characteristics. In Tieguanyin oolong tea, linalool, 3,5-octylodiene-2-one, linalool oxide, cis-jasmonone, dehydrolinalool, and α-terpineol showed diverse floral aromas, which were closely related to the characteristic aroma of Tieguanyin oolong tea. The key aroma components identified in Jinguanyin oolong tea included linalool, canalaldehyde, geranyl acetone, cis-jasmonone and isoeugenol, which were responsible for the characteristic sweet floral and woody aromas of Jinguanyin oolong tea.