RESUMEN
Penicillium exopolysaccharide (EPS) inhibits galactose lectins and enhances immunity. However, EPS production is low and its synthesis mechanism remains unclear. Penicillium EF-2 strains with high EPS production were selected for this study, and Penicillium fermentation conditions were subsequently improved. The optimal culture conditions were 30 g/L lactose, 6 g/L yeast extract powder, 4 d seed age, 10 % inoculation amount, 3 d of secondary fermentation time, and the final EPS yield was 3.97 g/L. UHPLC-Q-TOF-MS/MS was used to explore the mechanism of EPS synthesis at the metabolic level. Optimal carbon source: lactose and optimal nitrogen source: yeast extract can provide precursors for EPS synthesis through related metabolic pathways. Moreover, regulating the energy, vitamin, and lipid metabolic pathways created favourable conditions for EPS synthesis and secretion. These findings explain the mechanism of EPS synthesis at the metabolic level and provide a theoretical basis for optimising and industrialising EPS production.
Asunto(s)
Fermentación , Metabolómica , Penicillium , Espectrometría de Masas en Tándem , Penicillium/metabolismo , Penicillium/crecimiento & desarrollo , Metabolómica/métodos , Cromatografía Líquida de Alta Presión , Medios de Cultivo/química , Nitrógeno/metabolismoRESUMEN
In recent years, the considerable potential of endophytic bacteria and fungi as prolific producers of exopolysaccharides (EPSs) have attracted interest. In this study, 56 endophytes were isolated from Cyclocarya paliurus, and the secondary metabolites of EPSs were extracted from Monascus purpureus, Penicillium citrinum and Aspergillus versicolor, screened, and named MPE, PCE and AVE, respectively. In this work, the physicochemical properties and antioxidant activities of three EPSs, their cell proliferation activity on IEC-6 and RAW264.7 were investigated. The three EPSs were mainly composed of neutral sugar and differ in microstructure. However, MPE had a loose structure, and PCE exhibited a dense and sheet-like structure. In addition, the three EPSs performed ordinary antioxidant activity in vitro but showed excellent cell proliferation activity on IEC-6 and RAW264.7. The cell proliferation activity of PCE was 1.4-fold that of the controls at a concentration of 800 µg/mL on IEC-6, and MPE exhibited 1.3-fold increase on RAW264.7. This study provided scientific evidence and insights into the application of endophytes as a novel plant resource possessing huge application potential.
Asunto(s)
Antioxidantes , Proliferación Celular , Endófitos , Juglandaceae , Penicillium , Ratones , Animales , Antioxidantes/farmacología , Antioxidantes/química , Células RAW 264.7 , Endófitos/química , Endófitos/metabolismo , Proliferación Celular/efectos de los fármacos , Juglandaceae/química , Penicillium/química , Penicillium/metabolismo , Aspergillus/química , Aspergillus/metabolismo , Polisacáridos Fúngicos/química , Polisacáridos Fúngicos/farmacología , Polisacáridos Fúngicos/aislamiento & purificación , Monascus/química , Monascus/metabolismo , RatasRESUMEN
Nitrogen-doped carbon dots with excellent water- and ethanol-solubility were facilely prepared from plant cytoplasm via a one-step hydrothermal route and revealed as low-cost, label-free and highly sensitive and selective probes for detecting p-nitroaniline in both aqueous and soils owing to a proposed hydrogen-bonding effect.