Microbial reductions

Despite the progress made in the stereoselective synthesis of (R)-pantothenic acid since the mid-1980s, the commercial chemical synthesis still involves resolution of racemic pantolactone. Recent (ca 1997) synthetic efforts have been directed toward developing a method for enantioselective synthesis of (R)-pantolactone by either chemical or microbial reduction of ketopantolactone. Microbial reduction of ketopantolactone is a promising area for future research. 

Disinfection tests can be classified according to the test organism, ie, whether the test employs certain species of bacteria, fungi, or vimses classified as to whether it is a static test or a cidal test, as in a bactericidal vs bacteriostatic test or sporicidal vs sporistatic test or classified as to whether it is a microbial reduction test or an end-point test where all the organisms in the test are apparently killed. Procedures may be distinguished by in vitro or in vivo testing. Another way to consider tests is whether they are screening tests, practical type laboratory tests, or field tests. 

A relatively high degree of corrosion arises from microbial reduction of sulfates in anaerobic soils [20]. Here an anodic partial reaction is stimulated and the formation of electrically conductive iron sulfide deposits also favors the cathodic partial reaction. 

The chiral intermediate (S)-l-(2 -bromo-4 -fluorophenyl) ethanol was prepared by the enantioselective microbial reduction of 2-bromo-4-fiuoroacetophenone [lObj. Organisms from genus Candida, Hansmula, Pichia, Rhodotcnda, Saccharomyces, Sphingomonas, and baker s yeast reduced the ketone to the corresponding alcohol in... 

Recently, XAD was used as material to control the stereochemical course of microbial reductions [19], In the presence of XAD, simple aliphatic and aromatic ketones were reduced to the corresponding (S)-alcohols in excellent enantioselec-tivity while low enantioselectivities were observed in the absence of the polymer (Figure 8.23). 

Workman SL Woods, YA Gorby, JK Fredrickson, and MJ Trnex (1997) Microbial reduction of vitamin B,2 by Shewanella alga strain BrY with snbseqnent transformation of carbon tetrachloride. Environ Sci Technol 31 2292-2297. 

Carpentier W, K Sandra, I De Smet, A Brige J Van Beeuman (2003) Microbial reduction and precipitation of vanadium by Shewanella oneidensis. Appl Environ Microbiol 69 3636-3639. 

Lovley DR, EJP Phillips, YA Gorby, ER Landa (1991) Microbial reduction of uranium. Nature 350 413-416. 

Nealson KH, CR Myers (1992) Microbial reduction of manganese and iron new approaches to carbon cycling. Appl Environ Microbiol 58 439-443. 

Ortiz-Bernad I, RT Anderson, HA Vrionis, DR Lovley (2004a) Resistance of solid-phase U(VI) to microbial reduction during in situ bioremediation of uranium-contaminated groundwater. Appl Environ Microbiol 70 7558-7560. 

Bedard DL, H van Dort, KA Deweerd (1998) Brominated biphenyls prime extensive microbial reductive deha-logenation of Arochlor 1260 in Housatonic River sediment. Appl Environ Microbiol 64 1786-1795. 

Wu Q, DL Bedard, J Wiegel (1997a) Effect of incubation temperature on the route of microbial reductive dechlorination of 2,3,4,6-tetrachlorobiphenyl in polychlorinated biphenyl (PCB)-contaminated and PCB-free freshwater sediments. Appl Environ Microbiol 63 2836-2843. 

Griffin BM, JM Tiedje, FE Loftier (2004) Anaerobic microbial reductive dechlorination of tetrachloroethene to predominantly fra 5-l,2-dichloroethene. Environ Sci Technol 38 4300-4303. 

Bedard DL, JE Quensen III (1995) Microbial reductive dechlorination of polychlorinated biphenyls. In Microbial transformation and Degradation of Toxic Organic Chemicals (Eds LY Yonng, CE Cemiglia), pp. 127-216. Wiley-Liss, New York. 

Tas DO, IN Thomson, FE Loffler, SG Pavlostathis (2006) Kinetics of the microbial reductive dechlorination of pentachloroaniline. Environ Sci Technol 40 4467-4472. 

Mohn WW, JM Tiedje (1992) Microbial reductive dehalogenation. Microbiol Rev 56 482-507. 

He J, KR Robrock, L Alvarez-Cohen (2006) Microbial reductive debromination of polybrominated diphenyl ethers (PBDEs). Environ Sci Technol 40 4429-4434. 

Tas DO, SG Pavlostathis (2005) Microbial reductive transformation of pentachloronitrobenzene under metha-nogenic conditions. Environ Sci Technol 39 8264-8272. 

Lovley D, Philhps EJP, Gorby YA, Landa ER (1991) Microbial reduction of itraniitm. Nature 350 413-416 Lowson RT, Short SA, Davey BG, Gray DJ (1986) " U/ U and °Th/ " U activity ratios in mineral phases of a lateritic weathered zone. Geochim Cosmochim Acta 50 1697-1702 Ludwig KR (2003) Mathematical-statistical treatment of data and errors for h/U geochronology. Rev Mineral Geochem 52 631-636... 

In a very interesting and innovative study recently, the ultrasound-assisted microbial reduction of chromium [22], Mathur et al. reported the reduction of hexavalent chromium using Bacillus sp, isolated from tannery effluent contaminated site. The optimum reduction was found at pH 7 and 37°C. The percent reduction increased with an increase in biomass concentration and decreased with an increase in the initial concentration of hexavalent chromium. 

Kathiravan MN, Karthick R, Muthu N, Muthukumar K, Velan M (2010) Sonoassisted microbial reduction of chromium. Biochem Biotechnol 160(7) 2000-2013... 

Patel and coworkers reported that microbial reduction of ethyl l-benzyl-3-oxopiperidine-4-carboxylate by Candida parapsilosis SC16 347 gave ethyl cis-(3R,4R)-1 -benzyl-3AMiydro-xypiperidine-4/ -carboxylate as the major product in 97.4% diastereomeric excess (de) and 99.8% ee (Figure 7.2), while 99.5% de and 98.2% ee were achieved in the reduction catalyzed by Pichia methanolica SC16 415 [14]. 

Figure 7.2 Synthesis of ethyl cis-(3R,4R) I -henzyl-3I -hydroxypiperidine-4R-carboxylate via microbial reduction...

Bertau, M. and Burli, M. (2000) Enantioselective microbial reduction with baker s yeast on an industrial scale. Chimia, 54 (9), 503-507. 

Guo, Z., Patel, B.P., Corbett, R.M. et al. (2006) Stereospecific microbial reduction of ethyl l-benzyl-3-oxo-piperidine-4-carboxylate. Tetrahedron Asymmetry, 17 (13), 2015-2020. 

Oliver D.D., Brockman F.J., Bowman R.S., Kieft T.L. Microbial reduction of hexavalent chromium under vadose zone conditions. J Environ Qual 2003 32 317-324. 

---