Immobilization of P. Digitatum and Bioconversion of Limonene to Alpha-Terpineol.

The parameters of bioconversion of limonene to $\alpha$-terpineol by Penicillium digitatum were determined. This bioconversion was carried out stereo-specifically and selectively by this fungus. (R)-(+)-limonene was selectively converted to (R)-(+)-$\alpha$-terpineol by mycelia of this fungus during early growth phase. Immobilization of the fungal mycelia for use in continuous production of this product was possible. Aeration was critical to this bioconversion. The optimum aeration was about 1.6 mg/L for growing cells and immobilized cells. Substrate inhibition of the bioconversion was not observed when the substrate concentration was below 4% (v/v). End product inhibition was observed. The \rm Ki\sb{app} was 12.08 mM. The optimum temperature was 28\sp\circC. Optimum pH was 4.5 for resting cells and 7.0 for immobilized cells. The optimum substrate contact time for this bioconversion was 1 to 2 days and 3 to 4 days for free cells and immobilized cells respectively. Several organic solvents and detergents were found to increase bioconversion yield for free and immobilized fungal cells. The half-life of immobilized mycelia was dependent on the amount of aeration. At the 0.3 SLPM aeration, the half-life of immobilized fungal mycelia was about 7 days

Online-offline activities and game-playing behaviors of avatars in a massive multiplayer online role-playing game

Massive multiplayer online role-playing games (MMORPGs) are very popular in China, which provides a potential platform for scientific research. We study the online-offline activities of avatars in an MMORPG to understand their game-playing behavior. The statistical analysis unveils that the active avatars can be classified into three types. The avatars of the first type are owned by game cheaters who go online and offline in preset time intervals with the online duration distributions dominated by pulses. The second type of avatars is characterized by a Weibull distribution in the online durations, which is confirmed by statistical tests. The distributions of online durations of the remaining individual avatars differ from the above two types and cannot be described by a simple form. These findings have potential applications in the game industry.Comment: 6 EPL pages including 10 eps figure