Open AccessBiomachining: Preservation of Acidithiobacillus ferrooxidans and treatment of the liquid residue
Author(s) -
DíazTena Estíbaliz,
Rojo Naiara,
Gurtubay L.,
RodríguezEzquerro Adrián,
López de Lacalle Luis Norberto,
Oyanguren Iñigo,
Barbero Francisca,
Elías Ana
Publication year - 2017
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201600124
Subject(s) - chemistry , cryoprotectant , environmentally friendly , acidithiobacillus ferrooxidans , microorganism , residue (chemistry) , biodegradation , chemical engineering , hydroxide , bacteria , pulp and paper industry , copper , bioleaching , organic chemistry , cryopreservation , biology , embryo , ecology , genetics , engineering , microbiology and biotechnology
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.