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Laboratory‐scale continuous reactor for soluble selenium removal using selenate‐reducing bacterium, Bacillus sp. SF‐1
Author(s) -
Fujita Masanori,
Ike Michihiko,
Kashiwa Masami,
Hashimoto Ryoko,
Soda Satoshi
Publication year - 2002
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.10425
Subject(s) - selenate , selenium , chemostat , chemistry , anoxic waters , bioreactor , anaerobic exercise , nuclear chemistry , bacteria , chromatography , environmental chemistry , biology , organic chemistry , genetics , physiology
A model continuous flow bioreactor (volume 0.5 L) was constructed for removing toxic soluble selenium (selenate/selenite) of high concentrations using a selenate‐reducing bacterium, Bacillus sp. SF‐1, which transforms selenate into elemental selenium via selenite for anaerobic respiration. Model wastewater contained 41.8 mg‐Se/L selenate and excess lactate as the carbon and energy source; the bioreactor was operated as an anoxic, completely mixed chemostat with cell retention time between 2.2–95.2 h. At short cell retention times selenate was removed by the bioreactor, but accumulation of selenite was observed. At long cell retention times soluble selenium, both selenate and selenite, was successfully reduced into nontoxic elemental selenium. A simple mathematical model is proposed to evaluate Se reduction ability of strain SF‐1. First‐order kinetic constants for selenate and selenite reduction were estimated to be 2.9 × 10 −11 L/cells/h and 5.5 × 10 −13 L/cells/h, respectively. The yield of the bacterial cells by selenate reduction was estimated to be 2.2 × 10 9 cells/mg‐Se. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 755–761, 2002.