The kinetics of ferrous-iron oxidation by Leptospirillum ferriphilum in continuous culture: the effect of pH

 

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dc.contributor.author Ojumu, T V
dc.contributor.author Petersen, J
dc.date.accessioned 2016-08-17T09:36:01Z
dc.date.available 2016-08-17T09:36:01Z
dc.date.issued 2011
dc.identifier http://dx.doi.org/10.1016/j.hydromet.2010.11.007
dc.identifier.citation Ojumu, T. V., & Petersen, J. (2011). The kinetics of ferrous ion oxidation by Leptospirillum ferriphilum in continuous culture: the effect of pH. Hydrometallurgy, 106(1), 5-11. en_ZA
dc.identifier.issn 0304-386X en_ZA
dc.identifier.uri http://hdl.handle.net/11427/21287
dc.identifier.uri http://www.sciencedirect.com/science/article/pii/S0304386X10003014
dc.description.abstract The kinetics of ferrous ion oxidation by Leptospirillum ferriphilum were studied in continuous culture with a focus on the effect of solution pH (pH 0.8–2.0), assuming that the effect of pH on cell metabolism can be independently studied of reactor context and other reactions common in bioleach heaps. A simplified competitive ferric ion inhibition model and the Pirt Equation were used to analyze the experimental data. The results showed that the maximum specific activity of L. ferriphilum has a symmetrical bell-shaped curve relationship with pH. The maximum specific ferrous-iron oxidation rate,qFe2 +maxgave a highest value of 14.54 mmol Fe2+(mmol C h)− 1 at pH 1.3, and was described by a quadratic function. The steady state carbon biomass in the reactor and the apparent affinity constant, K′Fe2 +, also increased with increase in pH; however, a slight increase in the carbon biomass was observed beyond pH 1.6. The results also showed that ferric ion precipitation is significant beyond pH 1.3 and about 13% total iron from the feed was lost at pH 2.0. The maximum biomass yield increased linearly with pH, while the culture maintenance coefficient was significantly small in all experiments and was minimum at pH 1.3. The values are indicative of actively growing chemostat cultures. This study shows that microbial ferrous ion oxidation by L. ferriphilum may be sustained at pH lower than pH 0.8 as the microbial activity is much higher than reported values for common mesophilic acidophiles. This may have implications on how bioleach heap operations can be started-up to improve metal recovery. en_ZA
dc.language eng en_ZA
dc.publisher Elsevier en_ZA
dc.source  Hydrometallurgy en_ZA
dc.source.uri http://www.sciencedirect.com/science/journal/0304386X
dc.subject.other Microbial ferrous ion oxidation
dc.subject.other Kinetics
dc.subject.other pH effect
dc.subject.other Bioleaching
dc.subject.other Leptospirillum ferriphilum
dc.title The kinetics of ferrous-iron oxidation by Leptospirillum ferriphilum in continuous culture: the effect of pH en_ZA
dc.type Journal Article en_ZA
dc.date.updated 2016-08-17T09:32:32Z
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Ojumu, T. V., & Petersen, J. (2011). The kinetics of ferrous-iron oxidation by Leptospirillum ferriphilum in continuous culture: the effect of pH. <i> Hydrometallurgy</i>, http://hdl.handle.net/11427/21287 en_ZA
dc.identifier.chicagocitation Ojumu, T V, and J Petersen "The kinetics of ferrous-iron oxidation by Leptospirillum ferriphilum in continuous culture: the effect of pH." <i> Hydrometallurgy</i> (2011) http://hdl.handle.net/11427/21287 en_ZA
dc.identifier.vancouvercitation Ojumu TV, Petersen J. The kinetics of ferrous-iron oxidation by Leptospirillum ferriphilum in continuous culture: the effect of pH.  Hydrometallurgy. 2011; http://hdl.handle.net/11427/21287. en_ZA
dc.identifier.ris TY - Journal Article AU - Ojumu, T V AU - Petersen, J AB - The kinetics of ferrous ion oxidation by Leptospirillum ferriphilum were studied in continuous culture with a focus on the effect of solution pH (pH 0.8–2.0), assuming that the effect of pH on cell metabolism can be independently studied of reactor context and other reactions common in bioleach heaps. A simplified competitive ferric ion inhibition model and the Pirt Equation were used to analyze the experimental data. The results showed that the maximum specific activity of L. ferriphilum has a symmetrical bell-shaped curve relationship with pH. The maximum specific ferrous-iron oxidation rate,qFe2 +maxgave a highest value of 14.54 mmol Fe2+(mmol C h)− 1 at pH 1.3, and was described by a quadratic function. The steady state carbon biomass in the reactor and the apparent affinity constant, K′Fe2 +, also increased with increase in pH; however, a slight increase in the carbon biomass was observed beyond pH 1.6. The results also showed that ferric ion precipitation is significant beyond pH 1.3 and about 13% total iron from the feed was lost at pH 2.0. The maximum biomass yield increased linearly with pH, while the culture maintenance coefficient was significantly small in all experiments and was minimum at pH 1.3. The values are indicative of actively growing chemostat cultures. This study shows that microbial ferrous ion oxidation by L. ferriphilum may be sustained at pH lower than pH 0.8 as the microbial activity is much higher than reported values for common mesophilic acidophiles. This may have implications on how bioleach heap operations can be started-up to improve metal recovery. DA - 2011 DB - OpenUCT DP - University of Cape Town J1 -  Hydrometallurgy LK - https://open.uct.ac.za PB - University of Cape Town PY - 2011 SM - 0304-386X T1 - The kinetics of ferrous-iron oxidation by Leptospirillum ferriphilum in continuous culture: the effect of pH TI - The kinetics of ferrous-iron oxidation by Leptospirillum ferriphilum in continuous culture: the effect of pH UR - http://hdl.handle.net/11427/21287 ER - en_ZA


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