Characterisation of the simultaneous molybdenum reduction and glyphosate degradation by Burkholderia vietnamiensis AQ5-12 and Burkholderia sp. AQ5-13

Abstract

In this novel study, we report on the use of two molybdenum-reducing bacteria with the ability to utilise the herbicide glyphosate as the phosphorus source. The bacteria reduced sodium molybdate to molybdenum blue (Mo-blue), a colloidal and insoluble product, which is less toxic. The characterisation of the molybdenum-reducing bacteria was carried out using resting cells immersed in low-phosphate molybdenum media. Two glyphosate-degrading bacteria, namely AQ5-12 and sp. AQ5-13, were able to use glyphosate as a phosphorous source to support molybdenum reduction to Mo-blue. The bacteria optimally reduced molybdenum between the pHs of 6.25 and 8. The optimum concentrations of molybdate for strain AQ5-12 was observed to be between 40 and 60 mM, while for sp. AQ5-13, the optimum molybdate concentration occurred between 40 and 50 mM. Furthermore, 5 mM of phosphate was seen as the optimum concentration supporting molybdenum reduction for both bacteria. The optimum temperature aiding Mo-blue formation ranged from 30 to 40 °C for AQ5-12, whereas for sp. AQ5-13, the range was from 35 to 40 °C. Glucose was the best electron donor for supporting molybdate reduction, followed by sucrose, fructose and galactose for both strains. Ammonium sulphate was the best nitrogen source in supporting molybdenum reduction. Interestingly, increasing the glyphosate concentrations beyond 100 and 300 ppm for AQ5-12 and sp. AQ5-13, respectively, significantly inhibited molybdenum reduction. The ability of these bacteria to reduce molybdenum while degrading glyphosate is a useful process for the bioremediation of both toxicants.

Soil properties and sulfur-oxidizing bacterial diversity in response to different planting patterns of shallot (Allium ascalonicum)

“…Belonging to the genus Burkholderia, B. cepacia is very useful for bioremediation of endosulfan-contaminated soil (Kumar et al 2008) and usually used as a bioinoculant in agriculture (Khambalkar and Sridar 2015). Klebsiella and Burkholderia can grow well at soil pH of 7 (Lin et al 2015;Manogaran et al 2018;Satapute and Kaliwal 2016), while maximum oxidation of sulfur to sulfate by Klebsiella sp. reaches on a medium with a pH of 7 (Behera et al 2016).…”

Production of molybdenum blue by two novel molybdate‐reducing bacteria belonging to the genusRaoultellaisolated from Egypt and Iraq

“…Mo is essential for the growth of leguminous plants through its role in nitrogen fixation (Manogaran et al . ). Mo pollution has not often been reported due to its moderate toxicity to humans in spite of its significant toxicity towards ruminants (Shukor et al .…”

“…Bacterial‐based remediation of Mo involves reduction of Mo to a colloidal and insoluble less toxic Mo blue (Mo‐blue) (Manogaran et al . ).…”

“…Other cases of pollution by Mo and heavy metals come from scrap metal yards, scheduled heavy metal sludges and aquatic bodies near industrial complexes (Shukor et al 2006;Yin et al 2007;Shukor et al 2008). Mo is essential for the growth of leguminous plants through its role in nitrogen fixation (Manogaran et al 2018). Mo pollution has not often been reported due to its moderate toxicity to humans in spite of its significant toxicity towards ruminants (Shukor et al 2010).…”

“…Some microbes are able to degrade a variety of xenobiotics and detoxify heavy metals at the same time (Anu et al 2010;Chaudhari et al 2013;Bhattacharya et al 2014). Bacterial-based remediation of Mo involves reduction of Mo to a colloidal and insoluble less toxic Mo blue (Mo-blue) (Manogaran et al 2018).…”