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Hydrogen-Oxidizing Producers of Polyhydroxyalkanoates
Published in Martin Koller, The Handbook of Polyhydroxyalkanoates, 2020
Tatiana G. Volova, Ekaterina I. Shishatskaya, Natalia O. Zhila, Evgeniy G. Kiselev
Hydrogen-oxidizing bacteria began to attract practical interest in the early 1970s as a potential regenerative component in closed biotechnological life support systems. Biosynthesis of hydrogen-oxidizing bacteria in combination with electrolysis was proposed as a solution to the main issues of human life support during space flights: oxygen generation and carbon dioxide consumption, water treatment, and production of the protein part of the human diet. As hydrogen-oxidizing bacteria grow much faster than other chemotrophs, they have attracted the attention of researchers as a potential source of protein. Their metabolism and growth were extensively studied in the US, the Federal Republic of Germany, Japan, and the USSR (Russian Federation since 1991). The late 1980s and the early 1990s saw an upsurge of interest in hydrogen-oxidizing bacteria as very promising producers of polyhydroxyalkanoates (polyesters of alkanoic acids) – polymers similar to polypropylene, but degradable in the natural environment.
Investigation on Characteristic of Tritium Oxidation by Natural Soils
Published in Fusion Science and Technology, 2020
We have investigated the characteristic of tritium oxidation by hydrogen-oxidizing bacteria in a natural soil at room temperature from the viewpoint of engineering to realize a passive reactor as a complementary method of tritium oxidation using a precious metal catalyst. In our experiment, an efficiency of tritium oxidation by a natural soil was obtained under a moisture condition at room temperature in a wide range of hydrogen concentration from 0.5 to 10 000 ppm. The efficiency of tritium oxidation tended to decrease with increasing hydrogen concentration. The efficiency was the highest at a hydrogen concentration of 0.5 ppm, which equals the value of hydrogen concentration in air. Our results indicate that hydrogen-oxidizing bacteria could oxidize tritium efficiently under a condition of low concentration of hydrogen, room temperature, and high moisture. This shows an opposite tendency to a metal catalyst. Hence, it is found that a bioreactor using hydrogen-oxidizing bacteria could complement a conventional catalytic reactor using a precious metal catalyst.