Optimization of fermentation conditions of fig leaves and its effect on content of active ingredients.

In order to improve the extraction rate of active components in fig leaves, the fermentation of fig leaves by bacterial enzyme was studied. A strain of Stenotrophomonas maltophilia was isolated from fresh, frozen, and dried fig leaves using fig leaves as the sole carbon source. It was found that the coumarin content of fermented fig leaves was higher than that of unfermented fig leaves. Therefore, this bacterium strain was selected as the fermentation strain in this experiment. After fermentation for two days, the coumarin and terpenes contents in the fermentation broth were determined by colorimetry, and the culture conditions were optimized by single factor and orthogonal experiments. The results showed that the optimal fermentation mode was bacterial-enzyme co-fermentation, the optimal precursor was 8 mg/L of L-phenylalanine, the additional carbon source was 2 g/L maltose, the optimum nitrogen source was ammonium sulfate + peptone mixture of 3 g/L, and the optimum ratio of cellulase and pectinase was 1: 2. At the optimization condition, the contents of coumarins, terpenoids, flavonoids, and polysaccharides in the fermentation broth of fig leaves were increased by 92.66%, 59.40%, 44.68%, and 42.84% respectively. The content of polyphenols was 4.24 times higher than that before optimization. The study indicates that fig leaves fermentation can increase the content of its active components, and the study provides a basis for the development and utilization of fig leaves as a new feed additive. [ABSTRACT FROM AUTHOR]