Iron respiration

In environments lacking a suitable external electron acceptor - such as dioxygen, sulfate, or ferric iron - respiration is not possible. Here, many organic compounds may be metabolized by fermenting microorganisms. Microbes of this class may create ATP by a direct coupling mechanism, using a process known as substrate level phosphorylation, SLP with an ion translocation mechanism like that employed by respirers, as already described or by a combination of SLP and ion translocation.1... 

Dubiel M, Hsu CH, Chien CC, Mansfeld F, Newman DK (2002) Microbial iron respiration can protect steel from corrosion. App Environ Microbio 68 1440-1445... 

Short KA, Blakemore RP. 1986. Iron respiration-driven proton translocation in aerobic bacteria. J Bacteriol 167 729-31. 

In sediments that lie in coastal waters, organic carbon levels are high enough to support denitrification, iron respiration, sulfate reduction and methanogenesis. As shown in the idealized profile presented in Figure 12.3b, the depth of O2 penetration in organic-rich sediments is typically so shallow as to make the zones of aerobic respiration. 

The particulate iron(ni) maximum is deeper than that of the particulate Mn maximum. This reflects the lower energy yield of iron respiration and its fester rate of... 

It looks reasonable to hypothesize that globally ubiquitous iron oxides were incorporated into life development from the early evolutionary stage, but subsequent to the synthesis of simple amines and organic acids. The diffusion of sulfide across primitive membranes is also meaningful for the maintenance of the thioester world . An intracellular iron redox cycle, driven possibly by light and sulfide, could have supported chemosynthesis. Iron respiration and photometabolism could have processed on the external surface of vesicles. This would have contributed to a vectorial transport of thioesters and protons into vesicles and accordingly to the development of the early protonmotive transport system. 

The formation of methane by the methanogens is called carbon dioxide respiration, as described previously (p. 112). In general, cytochromes occur as the electron carrier in the respiration. Thus, some methanogens have cytochromes b and c. However, not all methanogens have cytochromes, as already mentioned. This may mean that carbon dioxide respiration is an early evolving stage of the respiration from the noncytochrome-type to the cytochrome-type. The electron transfer systems of the sulfur respirers contain cytochrome b or cytochromes b and c (Hedderich et al., 1999). In the iron respiration system of Pyrobaculum islandicum, cytochrome b seems to participate in the Fe(III) reducing system (Childers and Lovley, 2001). These results will show that the fundamental features of the respiration may have already been established in the hyperthermophilic chemolithoautotrophic archaea (Fig. 7.2). 

Pronk JT, Liem K, Bos P, Kuenen JG (1991a) Energy transduction by anaerobic ferric iron respiration in Thiobacillus ferrooxidans. Appl Environ Microbiol 57 2063-2068 Pronk JT, Meijer WM, Hazeu W, van Dijken JP, Bos P, Kuenen JG (1991b) Growth of Thiobacillus ferrooxidans on formic acid. Appl Environ Microbiol 57 2057-2062 Puustinen A, Wikstrom M (1991) The heme groups of cytochrome o from E. coli. Proc Natl Acad Sci USA 88 6122-6126... 

Multiheme cytochromes c play an important role in bacterial iron respiration. In this process, soluble Fe chelates or insoluble Fe oxides serve as terminal electron acceptors of the anaerobic respiratory chain. In Shewanella and Geobacter spp., the two most studied Fe -reducing organisms, a great increase in cellular multiheme c-type cytochromes is observed upon growth by iron respiration. In the case of the genus Shewanella, electron transport to Fe involves CymA in the cytoplasmic membrane, and several... 

K. Lee, D.K. Newman. Microbial iron respiration Impacts on corrosion processes. Applied Microbiology Biotechnology, Vol. 62, pp. 134—139, 2003. 

Obuekwe CO, Westlake DWS, Cook FD (1981) Effect of nitrate on reduction of ferric iron by a bacterium isolated from crude oil. CANJMICROBIOL (27) 692-697 Lee AK, Newman DK (2003) Microbial iron respiration impacts on corrosion processes, online, Appl Enviromnental Microbiol, No. 7... 

The unique periplasmic respiration for the oxidative fermentation of AAB is reminiscent of the hydrogen or iron respiration of some chemolithotrophs, and also some specific oxidative fermentation such as glucose oxidation, alcohol oxidation, or gluconate oxidation could be fotmd in some related oxidative bacteria of pseudomonads or enteric bacteria. Thus, in this chapter, it is described, including some speculation, how this unique oxidative fermentation is distributed within the microbial world, and how this system (specific periplasmic dehydrogenase or terminal ubiquinol oxidases) is evolved or acquired in AAB. 

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