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. 2016 Nov 9;17(4):382-391.
doi: 10.1002/elsc.201600124. eCollection 2017 Apr.

Biomachining: Preservation of Acidithiobacillus ferrooxidans and treatment of the liquid residue

Estíbaliz Díaz-Tena  1 , Naiara Rojo  2 , L Gurtubay  1 , Adrián Rodríguez-Ezquerro  3 , Luis Norberto López de Lacalle  3 , Iñigo Oyanguren  4 , Francisca Barbero  4 , Ana Elías  1
Affiliations

Biomachining: Preservation of Acidithiobacillus ferrooxidans and treatment of the liquid residue

Estíbaliz Díaz-Tena et al. Eng Life Sci. .

Abstract

Biomachining has become a promising alternative to micromachining metal pieces, as it is considered more environmentally friendly than their physical and chemical machining counterparts. In this research work, two strategies that contribute to the development of this innovative technology and could promote its industrial implementation were investigated: preservation of biomachining microorganisms (Acidithiobacillus ferrooxidans) for their further use, and making valuable use of the liquid residue obtained following the biomachining process. Regarding the preservation method, freeze-drying, freezing, and drying were tested to preserve biomachining bacteria, and the effect of different cryoprotectants, storage times, and temperatures was studied. Freezing at -80°C in Eppendorf cryovials using betaine as a cryoprotective agent reported the highest bacteria survival rate (40% of cell recovery) among the studied processes. The treatment of the liquid residue in two successive stages led to the precipitation of most of the total dissolved iron and divalent copper (99.9%). The by-products obtained (iron and copper hydroxide) could be reused in several industrial applications, thereby enhancing the environmentally friendly nature of the biomachining process.

Keywords: Acidithiobacillus ferrooxidans; Biomachining; Liquid residue treatment; Preservation of microorganisms.

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Figures

Figure 1
Figure 1
Growth of A. ferrooxidans on the three media tested: (A) Medium A, (B) Medium B, and (C) Medium C.
Figure 2
Figure 2
Concentration of A. ferrooxidans cells after freezing at –80°C in Eppendorff vials for 14 and 28 days and using different cryoprotectants.
Figure 3
Figure 3
Cell viability in the samples stored at –20ºC (A–C) and –80ºC (D–F) in commercial cryovials: (A) T = –20ºC, after 7 days; (B) T = –20ºC, after 14 days; (C) T = –20ºC, after 28 days; (D) T = –80ºC, after 7 days; (E) T = –80ºC, after 14 days and (F) T = –80ºC, after 28 days.
Figure 4
Figure 4
(A) Initial BLR, (B) BLR after Fe2+ oxidation (Stage I.i), (C) BLR after Fe(OH)3 precipitation and filtration (Stage I.iii), (D) BLR solution after precipitation of Cu2+ and (E) BLR solution after removal of Cu(OH)2 by filtration.
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References

    1. Ting, Y. P. , Senthil, Kumar A. , Rahman, M. , Chia, B. K. , Innovative use of Thiobacillus ferrooxidans for the biological machining of metals. Acta Biotechnol. 2000, 20, 87–96.
    1. Hocheng, H. , Jadhav, U. , Process of biological machining, in: Nee A. Y. C. (Ed.), Handbook of Manufacturing Engineering and Ttehcnology, Springer‐Verlag, London: 2015, pp. 1687–1713.
    1. Johnson, D. , Warner, R. , Shih, A. J. , Surface roughness and material removal rate in machining using microorganisms. J. Manuf. Sci. Eng. 2007, 129, 223–227.
    1. Hocheng, H. , Chang, J. H. , Jadhav, U. U. , Micromachining of various metals by using Acidithiobacillus ferrooxidans 13820 culture supernatant experiments. J. Cleaner Prod. 2012, 20, 180–185.
    1. Istiyanto, J. , Saragih, A. S. , Jo‐Ko, T. , Metal based micro‐feature fabrication using biomachining process. Microelectron. Eng. 2012, 98, 561–565

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