本文旨在針對微生物氧化亞鐵硫桿菌及氧化硫硫桿菌分泌之胞外聚合物對銅金屬進行蝕刻之研究。此二菌種對金屬有其特定的蝕刻能力，可對金屬進行加工。而其加工機制為菌體生長時會產生代謝物（胞外聚合物，EPS），此代謝物可將金屬氧化得到電子，菌體可於此過程中獲得所需能量。藉由此代謝過程，可對所需的工件進行加工。蝕刻過程中影響結果的因素有：微生物預培養時間、氧化亞鐵硫桿菌之EPS溶液中的三價鐵離子濃度、EPS溶液體積及銅試片面積等等，本研究探討不同參數與蝕刻行為對應之關係。
　　研究中顯示，氧化亞鐵硫桿菌經過三天的預培養時間產生的EPS已足夠對銅造成蝕刻，蝕刻過程中初始速率極快，蝕刻效果比純粹使用微生物進行蝕刻更好，但受溶液中銅離子濃度限制，當銅離子濃度隨著時間提高，蝕刻量會達到飽和，適合用於微量加工之工件。蝕刻過程中可採用二價鐵離子及三價鐵離子的濃度變化作為蝕刻效率的指標。
　　而氧化硫硫桿菌需八天的預培養時間，其EPS溶液對銅試片初始蝕刻速率較慢，但隨著時間逐漸加快，蝕刻速率隨之增加。可得到較高的總蝕刻量，適合需較大蝕刻量試片之加工。加工時氧化硫硫桿菌之EPS溶液中含有元素硫的成份，其功能為促進蝕刻作用的進行並能防止產生沉澱附著於試片上。

　　This study uses extracellular polymeric substance (EPS) secreted by bacteria Thiobacillus ferrooxidans and Thiobacillus thiooxidans to etch the copper. These two bacteria have the ability of etching metal. The etching mechanism is based on the metabolite (EPS) from growing bacteria. The EPS can oxidize metal by acquiring electron, and bacteria obtain the necessary energy in the course. Through the metabolism, one can machine the work piece. The factors influencing etching results include the pre-cultivation time, the concentration of ferric ion in the EPS solution of Thiobacillus ferrooxidans, the area of copper, and volume of solution. This study explores the correlation between these parameters and etching behavior.
　　In this study, the EPS of Thiobacillus ferrooxidans reaches maximum material removal rate after culture of 3 days. At the beginning of etching, the rate of etching is very fast, but the copper removal amount is limited by the concentration of copper ion in the solution. It is suitable for the work piece with small amount of machining. The indicator of material removal rate is the concentration of ferrous ion during the etching process.
　　The initial material removal rate of the EPS of thiobacillus thiooxidans is slow, but it is faster and faster. The total copper removal amount is more than thiobacillus ferrooxidans. It is suitable for large amount of machining. There is sulfur powder in the solution when etching copper, which increases the rate of machining and prevent the residue on copper sample.

[1] Y. Uno, T. Kaneeda, and S. Yokomizo, (1993) “Fundamental study on biomachining (machining of metals by Thiobacillus ferrooxidans).” Transactions of the Japan Society of Mechanical Engineers, Part C, Vol. 59, pp. 3199-3204.
[2] Y. Uno, T. Kaneeda, and S. Yokomizo, (1996a) “Fundamental study on biomachining (machining of metals by Thiobacillus ferrooxidans).” JSME International Journal, Series C, Vol. 39, pp. 837-842.
[3] Y. Uno, T. Kaneeda, S. Yokomizo, and T. Yoshimura, (1996b) “Fundamental study on electric field assisted biomachining,” Journal of the Japan Society for Precision Engineering, Vol. 62, pp. 540-543.
[4] D. Zhang, and Y. Li, (1998), “Studies on kinetics and thermodynamics of biomachining pure copper.” Science in China Series C Life Sciences, Vol. 42, pp. 57-62.
[5] M. Kumada, T. Kawakado, S. Kobuchi, Y. Uno, S. Maeda, H. and Miyuki, (2001) “Investigations of fine biomachining of metals by using microbially influenced corrosion - Differences between steel and copper in metal biomachining by using Thiobacillus Ferrooxidans.” Zairyo to Kankyo/ Corrosion Engineering, Vol. 50, pp. 411-417.
[6] S. Viamajala, B. Peyton, and J. Petersen, (2003) “Modeling chromate reduction in Shewanella oneidensis MR-1: development of a novel dual-enzyme kinetic model,” Biotechnology and Bioengineering, Vol. 83, No. 7, pp. 790-797.
[7] H. Dinh, J. Kuever, M. Mussmann, A. Hassel, M. Stratmann and F. Widdel, (2004) “Iron corrosion by novel anaerobic microorganisms.” Nature, Vol. 427(6977), pp. 829-832.
[8] Y. Kurosaki, M. Matsui, Y. Nakamura, K. Murai, and T. Kimura, (2003) “Material processing using microorganisms (An investigation of microbial action on metals).” JSME International Journal, Series C: Mechanical Systems, Machine Elements and Manufacturing, Vol. 46, pp. 322-330.
[9] G. Olson, (1991) “Rate of pyrite bioleaching by Thiobacillus ferrooxidans: Results of an interlaboratory comparison.” Applied Environmental Microbiology, Vol. 57 (3), pp. 642–644.
[10] Y.Konishi, H. Kubo, and S. Asai, (1992) “Bioleaching of zinc sulfide concentrate by Thiobacillus ferrooxidans,” Biotechnology and Bioengineering, Vol. 39, pp.66-74.
[11] C. Gomez, M. Blazquez, and A. Ballester, (1999) “Bioleaching of a Spanish complex sulphide ore bulk concentrate.” Minerals Engineering, Vol. 12, pp. 93-106.
[12] D. Bond, D. Holmes L. Tender and D. R. Lovley (2002) “Electrode-reducing microorganisms that harvest energy from marine sediments,” Science. 295:483-5.
[13] D. R. Lovley, E. Phillips, Y. Gorby, and E. Landa, (1991) “Microbial reduction of uranium,” Nature, Vol. 350, pp. 413-416.
[14] D. R. Lovley, (2003) “Cleaning up with genomics: applying molecular biology to bioremediation.” Nature Reviews, Vol. 1, pp. 35-44.
[15] S. Chaudhuri, and D.R. Lovley, (2003) “Electricity generation by direct oxidation of glucose in mediatorless microbial fuel cells.” Nature Biotechnology, Vol. 21, No. 10, pp. 1229-1232.
[16] H.L. Ehrlich, (1990) Geomicrobiology, 2nd edition. Marcel Dekker, Inc.New York, NY
[17] Courtesy of Water Services Ltd http://www.arvanitakis.com
[18] S. Childers, S. Ciufo, and D. R. Lovley., (2002) “Geobacter metallireducens accesses insoluble Fe(III) oxide by chemotaxis, ” Nature, 2002 Apr 18;416(6882):767-9
[19] T. Daulton, B. Little, K. Lowe, and J. Jones-Meehan, (2002) “Electron energy loss spectroscopy techniques for the study of microbial chromium(VI) reduction,” J Microbiol Methods, 2002 Jun;50(1):39-54.
[20] R. McDougall, J. Robson, D. Paterson, and W. Tee, (1997) “Bacteremia caused by a recently described novel Desulfovibrio species,” J Clin Microbiol, 1997 Jul;35(7):1805-8.
[21] Liu HL, Chiu CW, and Cheng YC., (2003) “The effects of metabolites from the indigenous Acidithiobacillus thiooxidans and temperature on the bioleaching of cadmium from soil.” Biotechnol Bioeng, 2003 Sep 20;83(6):638-45.
[22] I. Ortiz-Bernad, R. T. Anderson, H. A. Vrionis, and D.R. Lovley, (2004) “Vanadium respiration by Geobacter metallireducens: novel strategy for in situ removal of vanadium from groundwater.” Appl Environ Microbiol, 2004 May;70(5):3091-5.
[23] J. M. Senko, and J. F. Stolz, (2001) “Evidence for iron-dependent nitrate respiration in the dissimilatory iron-reducing bacterium Geobacter metallireducens.” Appl Environ Microbiol. 2001 Aug;67(8):3750-2.
[24] S. S. Middleton, R. B. Latmani, M. R. Mackey, M. H. Ellisman, B. M. Tebo, and C. S. Criddle, (2003) “Cometabolism of Cr(VI) by Shewanella oneidensis MR-1 produces cell-associated reduced chromium and inhibits growth.” Biotechnol Bioeng, 2003, 83(6):627-37.
[25] S. Viamajala, B. M. Peyton, R. K. Sani, W. A. Apel, and J. N. Petersen, (2004) “Toxic effects of chromium(VI) on anaerobic and aerobic growth of Shewanella oneidensis MR-1.” Biotechnol Prog, 2004, 20(1):87-95.
[26] S. Viamajala, B. M. Peyton, W. A. Apel, and J. N. Petersen, (2002)“Chromate/nitrite interactions in Shewanella oneidensis MR-1: evidence for multiple hexavalent chromium [Cr(VI)] reduction mechanisms dependent on physiological growth conditions.” Biotechnol Bioeng, 2003, 83(7):790-7.
[27] C. Schwalb, S. K. Chapman, and G. A. Reid, (2003) “The tetraheme cytochrome CymA is required for anaerobic respiration with dimethyl sulfoxide and nitrite in Shewanella oneidensis.” Biochemistry, 2003, 42(31):9491-7.
[28] W. Carpentier, K. Sandra, I. D. Smet, A. Brige, L. D. Smet, and J. V. Beeumen, (2003) “Microbial reduction and precipitation of vanadium by Shewanella oneidensis.” Appl Environ Microbiol, 2003, 69(6):3636-9.
[29] C. Liu, Y. A. Gorby, J. M. Zachara, J. K. Fredrickson, and C. F. Brown, (2002) “Reduction kinetics of Fe(III), Co(III), U(VI), Cr(VI), and Tc(VII) in cultures of dissimilatory metal-reducing bacteria.” Biotechnol Bioeng, 2002, 80(6):637-49.
[30] T. Rohwerder, T. Gehrke, K. Kinzler, and W. Sand, (2003) “Bioleaching review part A: Progress in bioleaching: fundamentals and mechanisms of bacterial metal sulfide oxidation.” Applied Microbiology Biotechnol, 63, 239-248.
[31] A. Schippers, P.G. Jozsa, and W. Sand, (1996) “Sulfur chemistry in bacterial leaching of pyrite.” Appl. Environ. Microbiol, 52, 3424-3431.
[32] W. Sand, T. Gehrake, P.G. Jozsa, and A. Schippers, (1999) “Direct versus indirect bioleaching.” In: Amils, R., Ballester, A. (Eds.) Biohyrodrometallurgy and the Environment Toward the Mining of the 21st Century, Part A. Elservier, Amsterdam, 27-49.
[33] W. Sand, T. Gehrake, P.G. Jozsa, and A. Schippers, (2001) “(Bio)chemistry of bacterial leaching-direct vs indirect bioleaching.” Hydrometallurgy, 51, 115-129.
[34] D. E. Rawlings, (2002) “Heavy metal mining using microbes.” Annu. Rev. Microbiology, 56, 65-91.
[35] T. Gehrke, R. Hallmann, and W. Sand, (1995) “Importance of exopolymers from Thiobacillus ferroxidans and Leptospirillum ferrooxidans for bioleaching.” In: Jerez C. A., Vargas T., Toledo H., Wiertz J. V. (Eds.), Biohydrometallurgical Processing, University of Chile, Stantiago 1, 1-11
[36] B. Escobar, G. Huerta, and J. Rubio, (1997) “Short communication: influence of LPS on the attachment of Thiobacillus ferrooxidans to minerals.” W. J. Microbiol. Biochem, 13, 593-594.
[37] C. Poglian, and E. Donati, (1999) “The role of exopolymers in the bioleaching of a non-ferrous metal sulphide.” J. Ind. Microbiol. Biotech, 22, 88-92.
[38] P. T. Hoa, L. Nair, and C. Visvanathan, (2003) “The effect of nutrients on extracellular polymeric substance production and its in fluence on sludge properties.” Water SA, 29 (4), 437-442
[39] N. Yoshida, and Y. Murooka, (1994) “Adsorption of bacterial cells to crystal particles of heavy metals: role electrostatic interaction.” J. Ferment. Bioeng, 77, 636-641.
[40] R. C. Blake II, M. M. Lyles, and R. C. Simmons, (1995) “Morphological and physical aspects of attachment of Thiobacillus ferrooxidans.” In: Jerez, C.A., Vargas, T., Toledo, H., Wiertz, J.V. (Eds.), Biohydrometallurgical Processing, vol. 1. University of Chile, Santiago, 13-22.
[41] http://www.arvanitakis.com/gr/c/bac_gal/thiobacillus_thiooxidans.htm
[42] W. Sand , T. Gehrke, (2006) “Extracellular polymeric substances mediate bioleaching/biocorrosion via interfacial processes involving iron(III) ions and acidophilic bacteria” Research in Microbiology, Vol. 157, pp. 49–56.