Teng Sun,Haiping Zhang,Zhe Dong,Zengshe Liu,Mingming Zheng
Phenolic acid glycerols (PAGs) are a group of rare phytochemicals found from potato periderm, which show great potential in the food, cosmetic and pharmaceutical industries. In this study, seven PAGs were enzymatically synthesized via transesterification of ethyl phenates (EPs) with glycerol by ultrasonic promotion. The conversions of 88.1–98.5% could be obtained in 1–9 h. Compared with the conventional stirring methods, the catalytic efficiency was significantly increased 11.0–44.0 folds by ultrasound assistance. The lipid peroxidation inhibition activity increased 8.1-fold and 14.4-fold compared to the parent phenolic acids (PAs). Furthermore, caffeoyl glycerol and feruloyl glycerol exhibited excellent antimicrobial activity against Escherichia coli compared to the corresponding PAs with minimum inhibitory concentration (MIC) decreasing 4–16-fold. The PAGs can also absorb a much wider and higher amount of the harmful UV-B rays than the corresponding PAs. The present strategy for facile synthesis of multifunctional PAGs paves the way for the development and application of natural phytochemicals and novel ingredients.
Monoglyceryl phenolic acids (MPAs) were known as the natural hydrophilic antioxidants which could be used in different fields such as food, pharmaceutical, cosmetic etc. A novel enzymatic route of MPAs synthesis by the alcoholysis of phenolic acid ethyl esters with glycerol under ultrasound irradiation in solvent free system was developed. Optimization of reaction parameters shows that a high conversion of above 97.4% can be obtained under the following conditions: phenolic acid ethyl esters to glycerol molar ratio of 1:10, with 6% catalyst (Novozym 435), at 60 °C and 200 rpm, with ultrasound input of 250 W, at 20 kHz frequency. Compared to the conventional stirring method, the activation energy for phenolic acid ethyl esters conversion was decreased from 65.0 kJ/mol to 32.1 kJ/mol under ultrasound promotion; the apparent kinetic constant (V m /K m ) increased above 1.2-folds; the lipase amount decreased to 50%; the time required for the maximum conversion reduced up to 3-folds without damaging the lipase activity, which is the fastest report for enzymatic synthesis of MPAs.
The nascent polypeptide-associated complex (NAC) is involved in various biological functions in eukaryotes which have been extensively studied in animals and plants, but its role in the biocontrol action of microorganisms needs to be better understood. In this study, we investigated the function of TbNACα , one of the subunits of NAC, in the biocontrol activity of Trichoderma breve T069 against Sclerotium rolfsii . The TbNACα gene was deleted from T. breve T069, and the Δ TbNACα mutant showed significantly reduced mycelial growth, spore production, and spore germination. Additionally, volatile substances from Δ TbNACα had no significant effect on S. rolfsii , while non-volatile substances significantly inhibited the growth of S. rolfsii . Transcriptome sequencing results showed that compared to wild-type T069, the Δ TbNACα mutant had 3,398 differentially expressed genes, mainly regulating the expression of genes related to secondary metabolite biosynthetic enzymes, hydrolases, and membrane transport proteins. Untargeted metabolomics identified 50 upregulated metabolites (27 in positive ion mode and 23 in negative ion mode) in crude extracts from Δ TbNACα mutant metabolite broth. Moreover, the metabolic substances of ethyl caffeate had the strongest activity against S. rolfsii , with an EC 50 of 107.15 μg·mL -1 . Quantitative Real-time PCR (qPCR) analysis revealed that genes involved in the ethyl caffeate synthesis pathway were significantly upregulated in Δ TbNACα strains. This study provides a basis for the negative regulation of ethyl caffeate synthesis and elucidates the antagonistic inhibition mechanism of TbNACα in T. breve T069.
危险品化学品经营许可证（带存储）