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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]

Aflatoxin B1 is a natural carcinogenic mycotoxin. The biological detoxification of aflatoxin could result in less environmental pollution, more moderate conditions, and less impact on food and feed, and be more convenient than physical and chemical methods. In this study, strain 13 with aflatoxin B1 degradation activity (67.47 ± 1.44%) was isolated and identified as Kocuria rosea. A uniform design was applied to optimize the degradation activity using a software Data Processing System, and a quadratic polynomial stepwise regression model was selected to investigate the relationships between the degradation rate and five independent variables. Furthermore, the optimal degradation conditions (culture temperature of 30 °C, culture time of 4.2 days, seawater ratio of 100%, pH of 7.11, and inoculation dosage of 0.09%) were verified with a degradation rate of 88 ± 0.03%, which was well matched with the predicted value (92.97%) of the model. Complete genome sequencing of Kocuria rosea, conducted with a combination of Illumina and single-molecule real-time sequencing, was used to analyze the genomic features and functions of the strain, which were predicted by the annotation based on seven databases, and may provide insights into the potential of Kocuria rosea, as well as providing a reference for degradation gene and protein mining. These results indicate that Kocuria rosea strain 13 has the ability to degrade aflatoxin B1 efficiently, and it also has the potential to provide aflatoxin-degrading enzymes. [ABSTRACT FROM AUTHOR]

Statistical experimental designs were employed to optimize culture conditions for cold-adapted lysozyme production of a psychrophilic yeast Debaryomyces hansenii. In the first step of optimization using Plackett-Burman design (PBD), peptone, glucose, temperature, and NaCl were identified as significant variables that affected lysozyme production, the formula was further optimized using a four factor central composite design (CCD) to understand their interaction and to determine their optimal levels. A quadratic model was developed and validated. Compared to the initial level (18.8 U/mL), the maximum lysozyme production (65.8 U/mL) observed was approximately increased by 3.5-fold under the optimized conditions. Practical Application: Cold-adapted lysozymes production was first optimized using statistical experimental methods. A 3.5-fold enhancement of microbial lysozyme was gained after optimization. Such an improved production will facilitate the application of microbial lysozyme. Thus, D. hansenii lysozyme may be a good and new resource for the industrial production of cold-adapted lysozymes. [ABSTRACT FROM AUTHOR]