Optimization of Ultrasonic-Assisted Extraction of Active Compounds from the Fruit of Star Anise by Using Response Surface Methodology

Studies on cellulase-ultrasonic assisted extraction technology for flavonoids from Illicium verum residues

Background

Illicium verum is widely cultivated in southern China especially in Guangxi province. Its fruits has been traditionally used in Chinese medicine. In recent years, it has been the industrial source of shikimic acid. Usually the residues after extracting shikimic acid are treated as waste. Thus, the aim of this study was to optimize the extraction conditions of cellulase-ultrasonic assisted extraction technology for flavonoids from I. verum residues.

Results

The optimum extraction conditions with a maximum flavonoids yield of 14.76 % are as follows: the concentration of ethanol is 51.14 %, the liquid–solid ratio is 20.52 mL/g, the enzymatic hydrolysis pH is 5.303, the sonication time is 60 min, the enzyme solution temperature is kept at 45 °C, the amount of added enzyme is 70 mg/g, the enzymatic hydrolysis time is 2 h and the crushed mesh size is 0.355–0.85 mm.

Conclusions

The data indicate that the cellulase-ultrasonic assisted extraction technology has the potential be used for the industrial production of flavonoids from I. verum.

Optimization of magnetosome production by Acidithiobacillus ferrooxidans using desirability function approach

Present study aimed to resolve the conflict between cell growth and magnetosome formation of Acidithiobacillus ferrooxidans (A. ferrooxidans) in batch experiments by applying response surface methodology (RSM) integrated a desirability function approach. The effects of several operating parameters on cell growth (OD600) and magnetosome production (Cmag) were evaluated. The maximum overall desirability (D) of 0.923 was achieved at iron concentration of 125.07mM, shake speed of 122.37rpm and nitrogen concentration of 2.40g/L. Correspondingly, the OD600 and Cmag were 0.522 and 1.196, respectively. The confirmation experiment confirmed that the optimum OD600 and Cmag obtained were in good agreement with the predicted values. The inductively coupled plasma atomic emission spectrometer (ICP-AES) and transmission electron microscopy (TEM) analyses revealed that the production of magnetosomes could be improved via optimization. X-ray diffraction (XRD) showed the magnetosomes are magnetite. Results indicated that RSM with a desirability function was a useful technique to get the maximum OD600 and Cmag simultaneously.