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Capillary Electrophoresis as a Promising Technique to Evaluate Metabolites Secreted by Fungal Biocontrol Agents

Carpio, Azahara, Ríos-Moreno, Alex, Garrido-Jurado, Inmaculada, Quesada-Moraga, Enrique, Arce, Lourdes
Chromatographia 2016 v.79 no.7-8 pp. 481-489
Metarhizium brunneum, biological control agents, capillary electrophoresis, culture media, entomopathogenic fungi, high performance liquid chromatography, human health, insecticides, metabolites, risk, risk assessment, secretion, solvents
Capillary electrophoresis (CE) with ultraviolet (UV) detection has been evaluated in this work as a valuable tool to use in the risk assessment of fungal biocontrol agents, that are entomopathogenic fungus used nowadays as an alternative to chemical insecticides. Compared to HPLC–UV methods, which are frequently used in this scientific field, the method proposed using CE-UV provided faster analyses, with low cost reagents, reduced solvent consumption and generated low levels of residues. Specifically, the secretion of destruxin (dtx) A by BIPESCO5, EAMa 01/58-Su and ART2825 strains from fungus Metarhizium brunneum, over 18 days in different conditions, was monitored. The recent interest in this metabolite resides in the fact that it could be a risk to human health and the environment. Results showed that BIPESCO5 and EAMa 01/58-Su strains cultivated in a complete culture medium produced dtx A at levels that could be directly analyzed by CE (BIPESCO5, which produced the highest dtx A concentration at day 9). However, for a minimal culture medium, a preconcentration step was necessary prior to the determination of this metabolite by CE-UV. C18 and HLB cartridges were successfully used to improve the sensitivity of the CE method when necessary. In addition, dtx A was not detected in ART2825 strain in any culture medium. All these results were in agreement with the values found in the literature using HPLC.