[Study on oil-soluble components obtained from the fruit of Evoldia rutaecarpa].

OBJECTIVE: To extract and isolate the biologic-active components of the oil-soluble components obtained from the fruit of Evodia rutaecarpa. METHODS: Various chromatographic techniques were used to isolate and purifie the biologic-active components, the IR and NMR spectra were used to identify the structure of this compound from Evodia rutaecarpa, and the content and the chemical structure was calibrated with a standard mixture was by TLC. RESULTS: A crystal compound was isolated from the Evodia rutaecarpa of Rutaceae, and was elucidated as oleanolic acid. CONCLUSION: The main chemical constituents of oil-soluble components obtained from the fruit of Evodia rutaecarpa are terpenoid compounds, the content of oleanolic acid is 1.8%.

Prediction of methane yield at optimum pH for anaerobic digestion of organic fraction of municipal solid waste.

A concept of methane yield at optimum pH was advanced and subsequently a mathematical model that simulates the optimal pH of a batch process for anaerobic digestion of organic fraction of municipal solid waste (MSW) was developed and validated. The model was developed on the basis of the microbial growth kinetics and was divided into three processes: hydrolysis of substrates by hydrolytic bacteria, consumption of soluble substrate by acidogenic bacteria, and finally consumption of acetate and methane generated by methanogenic bacteria. Material balance and liquid phase equilibrium chemistry were used in this study. A series of experiments were conducted to validate the model. The model simulation results agreed reasonably with experimental data in different temperatures and total solid (TS) concentrations under uncontrolled pH. A computer circulation program was used to predict the optimal pH in different conditions. Experiments in different temperatures and TS were run under optimal pH which predicted by the model. The model was succeeded in increasing the methane production and the cumulative methane production had an average increment about 35% in optimal pH of different temperatures and TS.

[Kinetic of pH control in anaerobic digestion of organic fraction of municipal solid waste in a batch reactor].

Using a material and ionization balance analysis of anaerobic digestion process, a kinetic model of pH control in a batch anaerobic digestion of organic fraction of municipal solid waste was established on the basis of substrate decay and microbial growth kinetics, and a corresponding computer soft ware was created. The optimal pH in different anaerobic digestion can be predicted by this model. Consequently the maximal methane production can be obtained in anaerobic system by controlling the pH in optimal value. Comparative experiments were conducted to validate the model. The experiments demonstrated that the methane production of anaerobic system under optimal pH was steadier than the same condition under uncontrolled pH, and the cumulative methane production had an average increment about 20%.