Interaction of Acidithiobacillus ferrooxidans , Rhizobium phaseoli and Rhodotorula sp. in bioleaching process based on Lotka–Volterra model|
Zheng, Xuecheng & Li, Dongwei
Background: Nowadays, leaching-ore bacteria, especially Acidithiobacillus ferrooxidans is widely used to retrieve
heavy metals, many researches reflected that extra adding microorganism could promote bioleaching
efficiency by different mechanisms, but few of them discussed the interaction between microorganisms and
based on growth model. This study aimed to provide theoretical support for the collaborative bioleaching of
multiple microorganisms by using the Lotka–Volterra (L–V) model.
Results: This study investigated the interaction of Acidithiobacillus ferrooxidans, Rhizobium phaseoli, and
Rhodotorula sp. Results showed that the individual growth of the three microorganisms fit the logistic curves.
The environmental capacities of A. ferrooxidans, R. phaseoli, and Rhodotorula sp. were 1.88 × 109, 3.26 × 108,
and 2.66 × 108 cells/mL, respectively. Co-bioleaching showed mutualism between A. ferrooxidans and R. phaseoli with mutualism coefficients of α = 1.19 and β = 0.31, respectively. The relationship between A. ferrooxidans and Rhodotorula sp. could be considered as commensalism. The commensalism coefficient γ of the
effect of Rhodotorula sp. on A. ferrooxidans was 2.45. The concentrations of A. ferrooxidans and R. phaseoli were
3.59 × 109 and 1.44 × 109 cells/mL in group E, respectively, as predicted by the model. The concentrations of A. ferrooxidans and Rhodotorula sp. were 2.38 × 109 and 2.66 × 108 cells/mL, respectively. The experimental peak
values of the concentrations in microorganism groups E and F were detected on different days, but were quite
close to the predicted values.
Conclusion: The relationship among microorganisms during leaching could be described appropriately by Lotka–
Volterra model between the initial and peak values. The relationship of A. ferrooxidans and R. phaseoli could be
considered as mutualism, whereas, the relationship of A. ferrooxidans and R. phaseoli could be considered as
Cell concentration; Collaboration; Commensalism; Mutualism