Studies And Application Of Exopolysaccharides Produced By Inocutis Tamaricis And Funalia Trogii

Fungal exopolysaccharides (EPS) are biological macromoleculars that own significantbioactivities. Inocutis tamaricis and Funalia trogii are popularily distributed wood rotmacrofungi and the study of EPS of which was seldom reported. In order to exploit the EPSproducts of the two fungi, the related applied basic research was carried out in the presenteddissertation. First, the two fungi were identified based on morphological characteristics andinternal transcribed spacer (ITS) sequence analysis. Second, employing one-factor-at-a-timemethod, the central composite design (CCD) and uniform design, the fermentation process ofEPS production of Inocutis tamaricis and Funalia trogii was optimized and the rheologicaland morphological characters of fermentation process were also studied using viscosity meterand photomicrography system. Third, the groups of EPSs were obtained from the culturefiltrates by sephadex column, and their molecular components and structures were examinedby a multiangle laser-light scattering (MALLS) with refractive index (RI) detector system,MALDI-TOFMS, GC/MS, amino acid analyzer, FI-IR and NMR. Fourth, the antioxidativeand antitumor activities of the EPS of the two fungi were assayed by byo-phenanthroline,ABTS, DPPH and MTT method. Last, to confer the application of EPS in tobacco industry,the transfer rate of EPS in mainstream cigarette smoke was studied by smoking machine, andthe effects of supplement of EPS in cigarettes on sensory quality were investigated by sensorysmoking experiment.The results suggested that the optimal conditions for EPS production of Inocutistamaricis6-27was as follows: sucrose64.09g/L, tryptone5.24g/L in distill water, pH8.0and culture temperature of25℃. Under the optimal conditions, the maximal EPS productionin shake flasks was5.89g/L. Fermentation in a5-l stirred-tank suggested that the viscositywas closely related with the residual sugars, EPS production and mycelial dry weight. TheEPS production, mycelial growth and nutrients consumption in optimized medium werehigher than those in basic medium. Two groups of EPSs (designated as Fr-I, and Fr-II) wereobtained by sephadex column purification. The weight-average molar masses of the Fr-I andFr-II were determined to be8.948×104and6.421×104g/mol, respectively. Moreover, the Fr-Iwas acidic polysaccharide with a mass of mannose and glucose.The EPS of I. tamaricis6-27 owned significant positive effects on radical scavenging with obvious dose-effect relationship.The results showed that the transfer rate of EPS of I. tamaricis6-27was1.4%-1.7%. Added incigrettes, the offensive odor of smoking was obviously decreased, the tobacco aroma wassmoothed, the sweetness of smoking was increased and the aftertaste was improved.The results suggested that the optimal conditions for EPS production of F. trogii insubmerged cultures were5%maltose,0.5%polypeptone,8.87mM KH2PO4, pH6and28℃.Under the optimal conditions, the maximal EPS production was8.68g/L. Fermentation in a5-l stirred-tank suggested that the viscosity was closely related with the residual sugars, EPSproduction and mycelial dry weight, and the EPS production, mycelial growth and nutrientsconsumption in optimized medium were higher than those in basic medium. Two groups ofEPSs (designated as Fr-I and Fr-II) were isolated by gel filtration chromatography usingSepharose CL-6B. The weight-average molar masses of the Fr-I and Fr-II were determined tobe1.007×105and2.393×104g/mol, respectively. The Fr-I was acetylization polysaccharidewith-glycosidic bond, and abundant of galactose, mannose and glucose (4.5:2.5:2.5).Meanwhile, Fr-II was proteoglycan with methoxylation β-glycosidic bond, containing glucose,mannose, galactose and talose (3:3:2.5:1). Pharmacological experiments indicated that EPS ofF. trogii were useful to the therapy of free radical injury and cancer diseases with obviousdose-effect relationship. The transfer rate of F. trogii EPS in cigarette smoke was2.3%-3.3%.The results of sensory experiments suggested that the optimal addition concentration of grossEPS in cigarette was0.04%. The study provided a theoretical basis for the application offungal EPS in tobacco industry.