Poly-P bacteria

One of the most interesting processes for phosphorus removal fi-om wastewaters is the enhanced biological phosphorus removal (EBPR). This process is based on the capacity of polyphosphate accumulating microorganisms (Poly-P bacteria) to store inside the cells large amounts of phosphorus, when submitted to alternation of anaerobiosis and aerobiosis periods. In these bacteria, phosphorus and carbon metabolisms are closely... 

Fig 2 and 3 show granules of PHA inside Poly-P bacteria stained with Nile blue by bright field microscopy and by epyfluorescence microscopy,... 

PHA production by Poly-P bacteria remains at relatively low levels (around 20% of the sludge dry weight). The reported values were obtained in processes where optimisation of phosphorus removal was the main concern, polymer production being a side stream goal If the objective of the process is the PHA production, cells should be harvested at the end of anaerobiosis, when they are full of PHA. 

Table I. Composition on HB and HV, average molecular weight (M ), polydispersity (Mw/M ) and PHA yield produced by Poly-P bacteria using acetate, propionate and butyrate...

Phillips RL, Kim I-B, Carson BE, Tidbeck B, Bai Y, Lowary TL, Tolbert LM, Bunz UHF (2008) Sugar-substituted poly(p-phenyleneethynylene)s sensitivity enhancement toward lectins and bacteria. Macromolecules 41 7316-7320... 

Another interesting example of lactones are the p-hydroxyalkanoates, whose ROP affords poly(p-hydroxyalkanoate)s (PHAs), a class of aliphatic polyesters naturally produced by bacteria (Fig. 3) [12, 13]. Poly(3-(R)-hydroxybutyrate) (PHB) is a typical example. PHB is a stiff thermoplastic material with relatively poor impact strength, but the incorporation of other monomers can improve the mechanical properties. 

Bacteria occasionally contain inclusion granules within their cytoplasm. These consist of storage material composed of carbon, nitrogen, sulphur or phosphorus and are formed when these materials are replete in the environment to act as repositories of these nutrients when limitations occur. Examples include poly-p-hydroxybutyrate, glycogen and polyphosphate. 

The first gene representing the NADKIN family was identified and cloned from M. tuberculosis and termed for the ability of the respective approximately 30-kDa recombinant protein to utilize polyphosphate (poly(P)) as an alternative phosphoryl donor in conversion of NAD into NADP. ° The same dual (ATP/poly(P)) specificity was later confirmed for a number of other NADKINs from Gram-positive bacteria and archaea. However, the enzymes from E. coli (gene nadK, formerly S. enterica ° and Sphingomonas sp. as well as... 

The enzymatic hydrolysis of poly-p-hydroxybutyrate, PHB, by several different bacteria, which are known to secrete active esterases, has been studied in some detail by several research groups [7, 8]. As with the polysaccharides, the final products of these degradation reactions are the monomers, dimers and trimers, which are removed by hydrolysis only from hydroxyl-end of the polymer chain, as follows ... 

Poly(p-hydroxybutyrate) occurs naturally as the optically active high-molecular-weight polyester in some bacteria (e.g. Bacterium megaterium) ... 

Some micro-organisms, especially bacteria, can synthesise aliphatic polyesters of the poly(p-hydroxy acid)-type, namely poly(P hydroxyalkanoates) (PHA). The natural compound is poly(p-hydroxy... 

Many bacteria are a potential source of naturally occurring polyesters, mainly poly(p-hydroxy alkanoate)s, with general structure... 

Boiandin AN, Kalacheva GS, Rodicheva EK, Volova TG (2008) Synthesis of reserve polyhydroxyalkanoates by luminescent bacteria. Mikrotnologiia 77 364-369 Borah B, Thakur PS, Nigam JN (2002) The influence of nutritional and environmental conditions on the accumulation of poly-P-hydroxybutyrate in Bacillus mycoides RLJ B-017. J Appl Microbiol 92 776-783... 

Zhu C, Yang Q, Liu L, Lv F, Li S, Yang G, et al. Multifunctional cationic poly(p-phenylene vinylene) polyelectrolytes for selective recognition, imaging, and killing of bacteria over mammalian cells. Adv Mater 2011 23(41) 4805-10. 

Poly(P D-hydroxy butyrate), with the monomeric unit, -(-OCH(CH3) CH2CO-)-, occurs as hydrophobic granules of 500 nm diameter in the cytoplasm of bacteria. The polymers have degrees of polymerization of about 23 000 and very narrow molar mass distributions. Poly()3-D-hydroxy butyrate) serves as a carbohydrate reserve for the bacteria in much the same way as starch is for plants. 

Unlike animal or plant cells, there is no endoplasmic reticulum to which ribosomes are bound. Bacteria contain storage deposits of certain building blocks. The volutin granules serve as a reserve source of phosphate and are themselves composed of polyphosphates. Poly-p-hydroxybutyrate (PHB) a Upid-Iike material, serves as a carbon and energy source. 

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