Yanzhen Wang

37 Optimization of supercritical carbon dioxide extraction conditions of Semen cassiae volatile oil using response surface methodology and antimicrobial activity detection

Objectives The objective of this project was to study the process of extracting Semen cassia. The volatile components of Semen cassia were analyzed using supercritical CO2 extraction (SCDE). Based on a single factor experiment, response surface methodology was used to investigate the extraction of volatile oil. According to the fitted curves under different conditions, the effects of pressure, temperature and time on extraction and interactions between various factors were determined. Antimicrobial activity was also measured. Methods A Box-Behnken central composite design method was used based on single factor experiments. The influence of extraction temperature, extraction time and extraction pressure on extraction yield was studied. The response surface method was employed to analyze the results of experiments. The disk diffusion method was used to detect the antimicrobial activity of Semen cassiae volatile oil. Results The results indicated that the optimum extraction conditions were as follows: extraction temperature 51°C, extraction time 3.22 hours and extraction pressure 25 MPa. Extraction yield reached 2.34%. The volatile oil of Semen cassiae extracted from the tested strains showed antimicrobial activity, with MIC values ranging from 2.5 to 5 mg/mL.Abstract 37 Figure 1 Responsive surfaces and contours Conclusions SCDE is a stable and efficient process. Semen cassiae volatile oil had antimicrobial activity which could provide a theoretical basis for application of this oil.

9 Studies on the optimization of submerged fermentation medium and conditions for Tricholoma matsutake

Background Tricholoma matsutake, a popular food and biopharmaceutical in Asia, displays various pharmacological activities. Submerged fermentation is an efficient way to produce mycelia and bioactive metabolites. Consequently, research groups are working to optimize submerged fermentation conditions. This study was conducted in an attempt to optimize the fermentation parameters for T. matsutake and its active ingredients by using statistical and mathematical techniques. Methods Chemometrics methods were employed to optimize the fermentation medium and conditions. Based on a single-factor optimization strategy, suitable carbon and nitrogen sources were obtained. The key medium components were then identified using a Plackett-Burman design (PBD) and further optimized using a Box-Behnken design (BBD). Response surface methodology (RSM) was further used to optimize the experimental results obtained from BBD. Based on the optimum medium, the culture conditions were further optimized using a single-factor optimization strategy. Results The optimum components of nutrient medium comprised (g/L): glucose 43.2, peptone 26.9, NaNO3 0.18, (NH4)2SO4 0.36, KH2PO4 2.0, MgSO4 7 H2O 0.5, and vitamin B1 0.15. The best production of mycelium was 22.66 g/L, which was 59% higher than that of the original culture. The suitable culture conditions were: initial pH 4.25, temperature 26° C, culture time 6 days, seed age 3 days, rotating speed 225 rpm, inoculation amount 5%, and 75 mL liquid volume in a 250 mL flask. The best production of mycelium was 24.2 g/L, which was 7.0% higher than that of the original culture. Conclusions In this study, we used chemometrics methods to optimize the fermentation medium and conditions for T. matsutake. Our finding provides experimental evidence that PBD, BBD and RSM are effective tools for mathematical modeling and factor analysis of a medium optimization process.