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To optimize the production conditions for exopolysaccharides with higher antioxidant activities from Xerocomus badius cultured in shrimp byproduct medium, Plackett-Burman design, path of steepest ascent, and response surface methodology were explored. Based on the results of Plackett-Burman design and path of steepest ascent, a Box-Behnken design was applied to optimization and the regression models. The optimal cultural condition for high yield and antioxidant activity of the exopolysaccharides was determined to be 10.347% of solid-to-liquid ratio, a 4.322% content of bran powder, and a 1.217% concentration of glacial acetic acid. Culturing with the optimal cultural conditions resulted in an exopolysaccharides yield of 4.588 ± 0.346 g/L and a total antioxidant activity of 2.956 ± 0.105 U/mg. These values are consistent with the values predicted by the corresponding regression models (RSD < 5%).

Background: Endophytes from ginseng plants may produce saponins through in vitro fermentation, and some saponins possess antioxidant activity. This study aimed to enhance the total saponin yield of an endophytic fungus isolated from wild ginseng, determine saponin types, and explore whether saponin extracts from optimized fermentation protocols have antioxidant activity. Methods: Umbelopsis dimorpha strain NSJG was fermented in liquid under different conditions. The types of saponins were analyzed by Liquid Chromatography/Mass Spectrometry (LC/MS). The antioxidant activity of saponin extracts was evaluated by measuring their hemolytic inhibition rate on erythrocytes. Results: The endophytic fungus strain NSJG produced 1.236 mg/mL total saponins through liquid potato dextrose (PD) fermentation. The total saponin concentrations of optimal protocols G-ED-8 (3.107 mg/mL) and G-DP-8 (2.045 mg/mL) were three times and twice that of G-PD. Saponin extracts from G-ED-8 and G-DP-8 contained seven and eight types of ginsenosides and had higher hemolysis inhibition rates on erythrocytes than Vitamin C (VC), which were 36.05% and 46.69%. Conclusions: The research highlights the potential implications of wild ginseng endophytic fungus strain NSJG for the in vitro production of ginsenosides and the development of novel antioxidants. [ABSTRACT FROM AUTHOR]

A liquid fermentation process to bioconvert shrimp by-products was developed with two species of fungi,Boletus edulisandSuillus bovinus. Angiotensin I-converting enzyme (ACE) inhibitory, antioxidant activities of bioconverted products and the deodorization effect of fungal bioconversion were determined. Two species of fungi could grow quickly in shrimp by-products medium and deodorize shrimp by-products. Bioconverted products had higher ACE inhibitory and antioxidant activities than control medium. Water extracts without crude polysaccharides from mycelia ofB. edulishad the highest ACE inhibitory activity (IC50= 0.084 ± 0.011 mg/mL). Crude exopolysaccharides ofB. edulishad higher antioxidant activity. Bioconversion with the fungus was proven to be a novel, practicable way to recycle shrimp by-products. [ABSTRACT FROM PUBLISHER]