Cultivation of hyperthermophilic archaea in capillary tubes resulting in improved preservation of fine structures

A method for cultivating hyperthermophilic archaea that results in very high cell densities and in improved structural preservation of the cells is described. Cellulose capillary tubes, originally introduced as containers for embedding for electron microscopy, were filled with cells, closed at both ends, and put into sterile culture medium. Within these capillaries, which serve as ultrafiltration chambers, cells could be cultivated to much higher cell densities than in regular cultures. The capillaries containing cells were processed for ultrathin-sectioning by fixation, freeze-substitution, and embedding. Using this cultivation procedure, centrifugation, which may destroy sensitive structural components, could be avoided, and the cells of hyperthermophilic archaea were well-preserved. These undisturbed cells revealed the following new structural features: (1) a high number of tubules in ultrathin-sections, indicating a well-preserved network of Pyrodictium cells and tubules; (2) “ultraflat areas” of Pyrodictium cells, with the two membranes being in direct contact and, at some places, bulging out, forming evaginations; (3) novel cell-to-cell connections between Thermoproteus cells and, similarly, between Pyrobaculum cells; and (4) a surface coat on Pyrobaculum aerophilum cells. The cultivation procedure offers distinct advantages over conventional techniques and might be applicable for improved electron microscopy of other sensitive microorganisms. Received: 21 November 1996 / Accepted: 16 June 1997     

Waste treatment in product specific life cycle inventories

In product specific Life Cycle Assessment the environmental impacts resulting from the disposal of the product under study frequently have a strong influence on the overall result. Since the major disposal system - the Municipal Solid Waste Incineration (MSWI) and the Sanitary Landfill (SL) - are complex processes specially adapted for the treatment of a large variety of different types of waste with varying input composition, the direct determination of the environmental impacts coming from a single input component for example by measurements is not practicable. Two methods (Part I: MSWI, Part II: SL) of allocating the inventory positions caused by the processes MSWI and SL to individual input fractions are presented. The approaches described are based on process modelling for the calculation of the material and energy inputs and outputs of the disposal systems. For the MSWI process the material related allocation is carried out by means of a study of difference: The input/output balance is calculated with the process model for two variants with different input compositions. The input for the first variant consists of waste of average composition enlarged by a small amount of special waste fraction under study. In the second variant the calculation is done with an input consisting only of waste with average composition. The difference formed between the results of process calculation for both variants gives the effects of the treatment of the waste fraction under study in the disposal process.