Abstract
A novel and efficient method, namely Solid-state fermentation combined with ionic liquid pretreatment and ultrasonic-assisted extraction (SSFIPU), was successfully established for the extraction of anthocyanins (ACs) from Schisandra chinensis residue samples. Additionally, an enzymatic combined with ionic liquid pretreatment and ultrasonic-assisted extraction technique (EIPU) was effectively developed to extract Schisandrin A (SDA) and Schizandrin B (SDB) from the residue after AC extraction. A comprehensive examination was conducted on ten crucial parameters of SSFIPU and eight essential parameters of EIPU. The Box-Behnken design was employed to optimize the influencing factors and precisely predict the optimal extraction conditions. The optimized conditions were as follows: For SSFIPU, with 4 mol/L [BMIM]BF(4), 7 % carbon, 5 % nitrogen, a material-reagent ratio of 1:3 g/mL, a bacterial solution concentration of 1 × 10(6) cfu/mL, a pH of 4, a fermentation time of 4 days, an ultrasonic power of 350 W, and an ultrasonic time of 30 min, an AC extraction yield of 1.173 mg/g was achieved, which was remarkably 23.46 times higher than that of ethanol reflux extraction (ERE). For EIPU, under the conditions of 4.2 mol/L [BMIM]BF(4), a cellulase content of 20 %, an enzyme hydrolysis time of 2.5 h, a material-reagent ratio of 1:13 g/mL, a pH of 5, an ultrasonic power of 450 W, and an ultrasonication time of 30 min, an SDA extraction yield of 0.306 mg/g was obtained, which was 8.5 times greater than that of ERE, and an SDB extraction yield of 0.260 mg/g was achieved, which was 6.8 times higher than that of ERE. During the experiment, [BMIM]BF(4) was successfully recovered with a recovery rate of 91.21 %. Consequently, the proposed environmentally friendly SSFIPU and EIPU methods have laid a solid foundation for the recovery of active ingredients from plant residues.