Bacteria Alcaligenes

The poly(HA) depolymerases of the bacteria Alcaligenes faecalis (strains AE122 and Tl), Comamonas acidovorans, Comamonas testosteroni, Comamonas sp., Pseudomonas fluorescens, Pseudomonas lemoignei, Pseudomonas stutzeri, Ralstonia pickettii, Streptomyces exfoliatus, and of the fungi Paecilomyces lilaci-nus, Penicillium funiculosum, and Penicillium pinophilum have been purified and characterized (for details see Table 1). Poly(HA) depolymerases share several characteristics ... 

The twelve l- N-carbamoylases derive from seven genera of bacteria Alcaligenes (1), Arthrobacter (1), Bacillus (4), Blastobacter (1), Clostridium (1), Flavobacterium (1), and Pseudomonas (3). Only four of the twelve enzymes have been purified to homogeneity, making a comparison of enzymatic properties difficult. Two of the Bacillus strains have been reported to be thermophilic and the enzymes enriched from these strains have been found to possess optimal temperatures approximately 10 to 20 °C higher than most of the other enzymes (Table 12.4-5). The pH-optima of all l-N-carbamoylases are between pH 7.5 and 8.5. Whereas hydantoinases are not always strictly L-specific[1271, a strictly L-specific carbamoylase, responsible for the optical purity of the amino acid produced with resting cells, has been identified in each strain. 

Until now, pseudoazurin has only been found in bacteria, e.g., in the denitrifying bacteria Alcaligenes faecalis and Achromobacter cycloclastes. It is the electron donor of the green copper-protein nitrite reductase which catalyses the reduction of nitrite (NO2) to nitrogen monoxide (NO) [86-89]. The physiological electron donor of pseudoazurin is as yet unknown [70]. Pseudoazurin has a molecular mass of approximately 13.5 kD and a chain length of about 123 amino acid residues [88]. The additional amino acids, as compared with plastocyanin, form the C-terminal end of the protein (Fig. 14). The pseudoazurins have redox potentials of about 230 mV [90,91]. 

Welan bacteria (alcaligenes spp.) single sugar side groups L-rhamnose or L-mannose are regularly linked in j6(l-3) linkage to a gellan backbone... 

A more recent biodegradable polymer is polyhydroxybutyrate-valerate copolymer (PHBV). These copolymers differ from many of the typical plastic materials in that they are produced through biochemical means. It is produced commercially by ICI using the bacteria Alcaligenes eutrophus, which is fed a carbohydrate. The bacteria produce polyesters, which are harvested at the end of the process. When the bacteria are fed glucose, the pure polyhydroxybutyrate polymer is formed, while a mixed feed of glucose and propionic acid will produce the copolymers. Different grades are commercially available that vary in the amount of hydroxyvalerate units and the presence of plasticizers. The pure hy-... 

Polyhydroxyalkanoate is a polyester identified in 1925 by the microbiologist Maurice Lemoigne. It can be synthesised by various bacteria (Alcaligenes Eutrophus, cyanobacteria). Lower concentrations of carbon, nitrogen and phosphorus sources increase the yield and the quality of the polymers produced (Steinbiichel, 2002). There are numerous potential applications for PHA (cosmetics containers, disposable articles, medical implants, paper coatings). Moreover, PHA can be formulated in many grades, from elastic products to crystalline ones, it is a good candidate for blends and easy to process with traditional equipment (Whitehouse, 2000). 

Carbamate hydrolysis is frequendy observed as the initial reaction for pesticides having carbamate bonds, such as aldicarb, carbofuran, carbaryl, and benomyl (eq. 12) (19). Numerous genera of carbamate-hydroly2ing bacteria have been identified, including Pseudomonas, Jhihrobacter, Bacillus, Nocardia, Achromobacter, Flavobacterium, Streptomyces, Alcaligenes, A spirillum, Micrococcus, and Bhodococcus. 

Arsenite is also an intermediate in the fungal biomethylation of arsenic (Bentley and Chasteen 2002) and oxidation to the less toxic arsenate can be accomplished by heterotrophic bacteria including Alcaligenes faecalis. Exceptionally, arsenite can serve as electron donor for chemolithotrophic growth of an organism designated NT-26 (Santini et al. 2000), and both selenate and arsenate can be involved in dissimilation reactions as alternative electron acceptors. 

Immobilization of neutral xenobiotics in soils by qnatemary ammoninm cations has been established, and its significance on the bioavailability of naphthalene to bacteria has been examined. Bioavailability was determined by the rates of desorption, and these differed between a strain of Pseudomonas putida and one of Alcaligenes sp. (Crocker et al. 1995). 

Reiner AM, GD Hegeman (1971) Metabolism of benzoic acid by bacteria. Accumulation of (-)-3,5-cyclo-hexadiene-l,2-diol-l-carboxylic acid by a mutant strain of Alcaligenes eutrophus. Biochemistry 10 2530-2536. 

A mutant strain of Alcaligenes eutrophus was used (Reiner and Hegeman 1971) to demonstrate that the initial step in the metabolism of 4-fluorobenzoate involves 1 2 dioxygenation to 4-fluoro-1,2-dihydrodihydroxybenzene-l-carboxylate. 4-Fluorobenzoate may be used for growth by several bacteria, and metabolites produced by a strain of Pseudomonas sp., which was also able to degrade... 

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