PDF Publication Title:
Text from PDF Page: 187
Biologically Produced Sulfur 177 Apart from the nature of the sulfur in the globules, the surface of these globules has been studied as well. Studies on sulfur globules produced by Al. vinosum showed that the sulfur particle is bounded by a protein mem- brane, which appears to be sulfur-free [7, 18]. The proteins of the membrane were isolated by extraction and separated by reversed-phase HPLC, reveal- ing three major proteins [37]. Proteins associated with sulfur globules of Thiocapsa roseopersicina appeared to correspond to the proteins on the sulfur globules of Al. vinosum. Later research was able to locate the genes responsible for the production of these proteins and it was concluded that sulfur globules in Al. vinosum are extracytoplasmic due to the presence of this protein cell membrane [27]. Such a cell membrane was also found for sulfur globules in B. alba, where it was called sulfur inclusion envelope [17]. The exact function of the protein is still not clear. Because of the similarity to proteins such as keratin or plant cell wall it has been suggested that the proteins have a structural rather than an enzymatic function [29]. The pro- teins might also prevent the crystallization of the sulfur in the globule [38]. 3.2 Extracellularly Stored Sulfur Sulfur globules produced by bacteria excreting the globules outside the cell membrane have also been studied. Especially for biotechnological applica- tions these sulfur compound oxidizing bacteria are interesting since they al- low an easy separation of the sulfur from the bacteria. In Fig. 5 sulfur glob- ules can be seen which have been excreted by a Thiobacillus bacterium. Steudel proposed a number of models for the composition of bacterial sulfur globules in which he did not always distinguish between intracellular- ly and extracellularly stored sulfur. In a model proposed for sulfur globules excreted by Acidithiobacillus ferrooxidans [39] the globules consist of a sul- fur nucleus (mainly S8 rings and small amounts of other sulfur rings) and Fig. 5 Scanning electron micrograph of sulfur excreting Thiobacillus [40]PDF Image | Topics in Current Chemistry
PDF Search Title:
Topics in Current ChemistryOriginal File Name Searched:
Elemental-Sulfur-und-Sulfur-Rich-Compounds-I.pdfDIY PDF Search: Google It | Yahoo | Bing
Sulfur Deposition on Carbon Nanofibers using Supercritical CO2 Sulfur Deposition on Carbon Nanofibers using Supercritical CO2. Gamma sulfur also known as mother of pearl sulfur and nacreous sulfur... More Info
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |