Two new species ofTalaromyces from Taiwan and Japan

Two new species ofTalaromyces, isolated from soils in Taiwan and Japan, are described and illustrated.Talaromyces eburneus, associated with aGeosmithia anamorph, is characterized by off-white colony on oatmeal agar, small pale yellow ascomata, and subglobose to ovoid ascospores with a smooth wall.Talaromyces muroii is characterized by restricted growth on Czapek agar, luteous ascomata, which are initiated by paired gametangia like those seen in members of the seriesFlavi, ellipsoidal and nearly smooth ascospores, and the absence of an anamorph.     

Thermophilic Carbon-Sulfur-Bond-Targeted Biodesulfurization

Petroleum contains many heterocyclic organosulfur compounds refractory to conventional hydrodesulfurization carried out with chemical catalysts. Among these, dibenzothiophene (DBT) and DBTs bearing alkyl substitutions are representative compounds. Two bacterial strains, which have been identified as Paenibacillus strains and which are capable of efficiently cleaving carbon-sulfur (C--S) bonds in DBT at high temperatures, have been isolated for the first time. Upon attacking DBT and its various methylated derivatives at temperatures up to 60(deg)C, both growing and resting cells of these bacteria can release sulfur atoms as sulfate ions and leave the monohydroxylated hydrocarbon moieties intact. Moreover, when either of these paenibacilli was incubated at 50(deg)C with light gas oil previously processed through hydrodesulfurization, the total sulfur content in the oil phase clearly decreased.     

Continuous Thermophilic Composting

Under complete mixing conditions, aerobic decomposition of mixed organic waste materials has been maintained continuously in the thermophilic phase in a 55-gal rotating drum. Temperatures ranged between 53 and 70 C. Raw material was added daily or every second day in amounts up to 18 lb per 100 lb of decomposing material. The weight of material removed ranged between 42 and 60% of the raw material added.

Factors influencing the operation of the composting unit were studied in detail.

     

Thermophilic adaptation of proteins

Hyperthermophilic organisms optimally grow close to the boiling point of water. As a consequence, their macromolecules must be much more thermostable than those from mesophilic species. Here, proteins from hyperthermophiles and mesophiles are compared with respect to their thermodynamic and kinetic stabilities. The known differences in amino acid sequences and three-dimensional structures between intrinsically thermostable and thermolabile proteins will be summarized, and the crucial role of electrostatic interactions for protein stability at high temperatures will be highlighted. Successful attempts to increase the thermostability of proteins, which were either based on rational design or on directed evolution, are presented. The relationship between high thermo-stability of enzymes from hyperthermophiles and their low catalytic activity at room temperature is discussed. Not all proteins from hyperthermophiles are thermostable enough to retain their structures and functions at the high physiological temperatures. It will be shown how this shortcoming can be surpassed by extrinsic factors such as large molecular chaperones and small compatible solutes. Finally, the potential of thermostable enzymes for biotechnology is discussed.     

嗜高温酶研究进展

生存于极端环境中的微生物称为极端微生物,其体内的酶称为极端酶。极端环境包括：（１）温度高于８０℃,如陆上地热喷泉和深海底热喷口;年均气温低于零度,如南北极地区。（２）压力巨大,如几千米深的海底。（３）ｐＨ＜２,如煤沉积层和富含硫的地热喷泉;ｐＨ＞１１...     

Thermophilic Microbial Metal Reduction

Thermophilic microorganisms can reduce Fe(III), Mn(IV), Cr(VI), U(VI), Tc(VII), Co(III), Mo(VI), Au(I, III), and Hg(II). Ferric iron and Mn(IV) can be used as electron acceptors during growth; the physiological role of the reduction of the other metals is unclear. The process of microbial dissimilatory reduction of Fe(III) is the most thoroughly studied. Iron-reducing prokaryotes have been found in virtually all of the recognized types of terrestrial ecosystems, from hot continental springs to geothermally heated subsurface sediments. Thermophilic iron reducers do not belong to a phylogenetically homogenous group and include representatives of many bacterial and archaeal taxa. Iron reducing thermophiles can couple Fe(III) reduction with oxidation of a wide spectrum of organic and inorganic compounds. In the thermophilic microbial community, they can fulfil both degradative and productive functions. Thermophilic prokaryotes probably carried out global reduction of metals on Earth in ancient times, and, at the same time, they are promising candidates for use in modern biotechnological processes.