Extraction and Fermentation‐Based Purification of Saponins from Sapindus mukorossi Gaertn.

Abstract In the present study, the extraction and purification of saponins from Sapindus mukorossi Gaertn. were examined for effective utilization of the saponin resource. Saponins were extracted from S. mukorossi Gaertn. using water. The conditions of the water extraction process, including extraction temperature, extraction time, number of times of extraction, and solvent‐material ratio were optimized. The yield of total Sapindus saponins (TSS) from the pericarp was 33.41 % and its purity in the extract was 45.71 %. The saponin solution was further concentrated to 1/6–1/7 of its original volume, and dried yeast BV818 that adapted to the concentrated Sapindus saponins solution (SW) was screened. The activation conditions, inoculum amount, fermentation temperature, and fermentation period were optimized. By using the dried yeast under optimized conditions, the purity was increased to 75.50 %. The yield of the byproduct ethanol was 5.33 % (w/v), while the content of TSS in the final product decreased from 18.29 to 15.30 % (w/v). These results could contribute to the development of industrial‐scale production of Sapindus saponins.