In-situ fermentation with gellan gum adding to produce bacterial cellulose from traditional Chinese medicinal herb residues hydrolysate.

In this study, bacterial cellulose was synthesized by Taonella mepensis from traditional Chinese medicinal herb residues hydrolysate. To overcome the inhibitory effect of fermentation environment, in-situ fermentation with gellan gum adding was carried out for the first time. After 10 days' static fermentation, both high-acyl gellan gum and low-acyl gellan gum adding showed certain beneficial effects for bacterial cellulose production that the highest bacterial cellulose yield (0.866 and 0.798 g/L, respectively) was 59% and 47% higher than that (0.543 g/L) without gellan gum adding. Besides, gellan gum based bacterial cellulose showed some better texture characteristics. Gellan gum was loaded in the nano network of bacterial cellulose, and gellan gum adding had some influence on the crystal structure and thermal degradation behaviors of bacterial cellulose but affected little on its functional groups. Overall, this in-situ fermentation technology is attractive for bacterial cellulose production from low-cost but inhibitory substrates.

[Removal of cadmium from extracts of Gentianae Radix et Rhizoma by gamma-mercaptopropyl-modified silica gel].

OBJECTIVE: To study the optimum process of removing cadmium irons from extracts of Gentianae Radix et Rhizoma with gamma-mercaptopropyl-modified silica gel (MPS) and assess its cadmium ion-removing property. METHOD: Static and dynamic adsorptions were adopted to detect the cadmium-removing rate. MPS' cadmium ion-removing property was assessed with such indicators as the cadmium-removing rate, the solid content and the HPLC fingerprint. RESULT: The process parameters of the static adsorption were as follows: 0.20 g x mL(-1) of concentration of extracts, 120 minutes of adsorption time and 15:1 between raw materials and MPS. The process parameters of the dynamic adsorption were as follows: 1:3.5 times between diameter and height, 0.20 g x mL(-1) of concentration of extracts, 0.9 mL x min(-1) of flow rate of the extracts and 50:1 between raw materials and MPS. Before and after the cadmium ion-removing process, the extracts showed no notable difference in solid content and HPLC fingerprint. CONCLUSION: gamma-mercaptopropyl-modified silica gel (MPS) can effectively remove cadmium ion from the extracts of Gentianae Radix et Rhizoma with an excellent cadmium ion-removing property.