Bulgarian Academy of Sciences

About: Bulgarian Academy of Sciences is a government organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Catalysis & Coupling constant. The organization has 17989 authors who have published 36276 publications receiving 642820 citations. The organization is also known as: Bulgarian Academy of Sciences，簡稱：BAS & Balgarska Akademiya na Naukite.

The effect of CeO2 on the surface and catalytic properties of Pt/CeO2–ZrO2 catalysts for methane dry reforming

Abstract: The CO2 reforming of CH4 over Pt catalysts supported on nanocrystalline mesoporous ZrO2 and CeO2–ZrO2 carriers was investigated at atmospheric pressure. The effect of CeO2 content (1–12 wt%) on the surface and catalytic properties of the catalysts was studied. It was found that the pre-treatment temperature and the concentration of CeO2 influence on the morphology of Pt particles. The calcination temperature as high as 1073 K leads to sintering of Pt particles deposited over zirconia- and CeO2-loaded zirconia substrates. Temperature-programmed reduction (TPR) results showed good reductive properties for Pt/CeO2–ZrO2 catalysts due to both, the high surface shell reduction of zirconia and the synergetic effect between Pt and CeO2. X-ray photoelectron spectroscopy (XPS) of reduced catalysts revealed the presence of different Pt oxidation state depending on the catalyst composition. Stabilization of partially oxidized platinum species by ceria was detected for the reduced Pt/CeO2–ZrO2 samples. An activation period was required for the stabilization of the activity of Pt/CeO2–ZrO2 catalysts. The high stability of Pt/CeO2–ZrO2 catalysts was related to the close contact between Pt and CeO2.

Bioprocessing of plant cell cultures for mass production of targeted compounds.

Abstract: More than a century has passed since the first attempt to cultivate plant cells in vitro. During this time, plant cell cultures have become increasingly attractive and cost-effective alternatives to classical approaches for the mass production of plant-derived metabolites. Furthermore, plant cell culture is the only economically feasible way of producing some high-value metabolites (e.g., paclitaxel) from rare and/or threatened plants. This review summarizes recent advances in bioprocessing aspects of plant cell cultures, from callus culture to product formation, with particular emphasis on the development of suitable bioreactor configurations (e.g., disposable reactors) for plant cell culture-based processes; the optimization of bioreactor culture environments as a powerful means to improve yields; bioreactor operational modes (fed-batch, continuous, and perfusion); and biomonitoring approaches. Recent trends in downstream processing are also considered.