Bacteria

Extremophile converts fatty-acids into energy: bacteria
 

Metabolic process of extremophile bacteria converts fatty acids into a variety of secondary compounds, including hydrogen, by running normal metabolism backwards.

 
  "It survives on a food so unrewarding it needs help disposing of its waste. Eking out an existence only by turning the normal chemistry of life back to front, the bacterium Syntrophus aciditrophicus is one of the most extreme-living organisms known. Now its genome has been sequenced and is yielding clues as to how it survives. It might even help us make hydrogen from waste. Robert Gunsalus of the University of California, Los Angeles, and colleagues identified 3169 genes in Syntrophus. The bacterium performs a key part of the carbon cycle by breaking down fatty acids--used by almost no other organisms as an energy source. To do this, its genes stand normal energy-generation reactions on their head (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0610456104). In normal respiration, organic compounds are oxidised, and the electrons this liberates are used to drive the production of the energy-storage molecule ATP. In Syntrophus the electrons go the opposite way as the bacterium turns fatty acids into a variety of breakdown products that it feeds on, plus hydrogen and the chemical formate. It survives only with the 'help' of other bacteria that hoover up the hydrogen and formate--otherwise it could not feed. Understanding the bacterium's metabolism will 'hopefully make biohydrogen production a reality', says Gunsalus." (Hooper 2007: 12) from issue 2600 of New Scientist magazine, 21 April 2007, page 12)
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Shape-shifting aids swimming: bacteria
 

Body of bacteria moves through water by shape-shifting.

 
  "On the scale of a bacterium, water is as viscous as treacle. This makes swimming difficult because a simple symmetrical stroke gets you nowhere: the recovery stroke pushes you as far back as the first part of the stroke pulled you forward. So these bacteria adopt different geometrical shapes during the first and second parts of the stroke to maximise the forward movement. Swimming robots and moving parts in nanomachines are already engineered in this way." (Hogan 2003:24)
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Membranes avoid freezing: bacteria
 

Membranes of some microbes continue to allow diffusion at cold temperatures by having a special fatty composition that keep them relatively fluid.

 
  "Bacteria have two skins, an outer one which is a stiff molecular mesh, through which molecules of food and water can diffuse fairly easily, and an inner one, elastic and membranous, which has to be very selectively permeable, so that nutrients can get in but the internal substances of the cell do not leak out. (This, by the way, is the skin which ice damages lethally; the outer layer is tougher and serves to keep out big molecules and to sustain the cell's shape). The cell membrane, as it is called, includes a lot of fat in its structure, and its permeability is very much influenced by fluidity of that fat…Psychrophiles have cell membranes of a special fatty composition, such that they are relatively fluid at temperatures near freezing point--and again they pay a price: their membranes become too fluid, and begin to melt, when the environment warms to the temperatures that most bacteria prefer." (Postgate 1994:28)
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By-products inhibit yeast and fungi: Pseudomonas aeruginosa
 

The metabolism of Pseudomonas aeruginosa produces products that inhibit yeast and fungal growth via the conversion of unsaturated fatty acids.

 
  "Bioconversion is a “green” technology that converts fatty acids into entirely new chemical compounds with antimicrobial, industrial or biomedical properties. The bioconversion reactions by Pseudomonas aeruginosa PR3 have been cited extensively among microbial systems that produce mono-, di- and tri-hydroxy fatty acid derivatives from unsaturated fatty acids (Kuo et al., 1998). Strain PR3, isolated from a waste water stream on a pig farm in Morton, IL, USA was found to convert oleic acid to a novel compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), which inhibits the laboratory growth of Candida albicans, a yeast that sometimes causes thrush and other infections in humans (Hou and Bagby, 1991). This strain was also found to convert ricinoleic acid to another novel compound 7,10,12-trihydroxy-8(E)-octadecenoic acid (TOD), which inhibits the rice blast fungus, raising the prospect for a biological fungicide against this pathogen (Kuo et al., 2001). These recently described compounds, from the microbial conversion of unsaturated fatty acids, are potential value-added products that will inhibit such pathogens." (Bajpai et al. 2008:136)
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