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The preparation of BaTiO 3 preceramic powders by calcination of barium titanium coordination complexes as opposed to BaCO 3 /TiO 2 mixtures offers advantages in terms of processibility and phase purity that are welldocumented. 2 The chemistry of the complexes employed is far from simple, however. Preparation of barium titanyl oxalate, 3 BaTiO(C 2 O 4 ) 2 ‚5H 2 O, requires strict control of reaction temperature, reaction time, and solution composition if material with the proper stoichiometry is to be obtained. 4 Barium titanium citrate, 5 BaTi(C 6 H 6 O 7 ) 3 ‚6H 2 O, can easily be prepared in pure form but utilizes a complex organic ligand. Finally, barium titanium catecholate, 6 BaTi(C 6 H 4 O 2 ) 3 ‚3H 2 O, requires a multistep preparation involving either concentrated sulfuric acid or equally corrosive TiCl 4 , while barium titanium alkoxides 7 and phenoxides 8 require inert-atmosphere techniques for their preparation. 9 We recently reported a new barium titanium glycolate complex, BaTi(C 2 H 4 O 2 ) 3 ‚4C 2 H 6 O 2 ‚H 2 O, 8 which is easily prepared from simple starting materials using benchtop procedures developed by others for the synthesis of analogous complexes BaSi(C 2 H 4 O 2 ) 3 ‚3.

This study investigates the diversity and the potential phosphorus-accumulating ability among the purple nonsulfur (PNS) bacteria. Traditional methods and molecular biotechniques were applied. Microscopic visualization using 4',6-diamidino-2-phenylindole staining as well as chemical analysis demonstrated that most of the isolated PNS bacteria presented different levels of phosphorus accumulation. Four of the pure cultures, denoted as Rhodopseudomonas palustris CC1, CC7, G11, and GE1, based on their differences in the PNS's pufM gene, exhibited higher internal phosphorus content compared to other isolated strains in this study. In addition, substantial polyphosphate accumulation was observed after the bacteria entered their stationary growth phase. Among them, the isolated R. palustris G11 could accumulate internal phosphorus up to 13%-15% of its cell dry weight under anaerobic illuminated incubation conditions. When the incubation status was switched from anaerobic to aerobic, the bacterial phosphorus content had a tendency to decrease slightly or remain about the same throughout the whole aerobic stage. The growth rate and biomass were higher when the PNS bacteria grew under photoheterotrophic conditions rather than the chemoheterotrophic ones. Furthermore, the environmental pH value could affect the contents of internal bacterial phosphate. Results of this study demonstrated that PNS bacteria are a group of the polyphosphate-accumulating organisms, of which this ability had never been properly studied. The conditions that PNS bacteria accumulating polyphosphate presented from this study were unique and showed characteristics that were different from the well-known enhanced biological phosphorus removal model.

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