Researchers reveal the mechanism of interaction between heavy metal (metalloid) elements and fungi

The interaction between microorganisms and metals includes biosorption, bioprecipitation, oxidation-reduction of metal ions by microorganisms, and complexation of microbial extracellular polymers (EPS) with metal ions. Studies have shown that EPS of bacteria and algae have strong complexation with heavy metals (Hg) and metalloids (As), which can effectively reduce the toxicity of heavy metal ions. So, do fungi have strong resistance to (like) heavy metals? What effect does metal have on the production and biochemical composition of fungi EPS? And will it cause complexation?

Associate Professor Song Wenjuan from the Environmental Pollution and Ecological Remediation Laboratory of Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences and Professor Michael Geoffrey Gadd from the Geomicrobiology Group of the University of Dundee in the United Kingdom jointly studied the effects of heavy metals and metalloids (e.g., Hg, Pb, As and Se) on the growth status of Aureobasidium pullulans, the yield and composition of EPS, and the complexation between EPS and metal ions.

Studies have found that Hg and Se not only inhibited the growth of the strain, but also influenced the composition of EPS. Selenium has no obvious quenching effect on EPS fluorescence, that is, there is no complexation between the Se and EPS. Our results are of great significance for understanding the tolerance of fungi to metals (metalloids), the role of EPS from fungi in the remediation of heavy metal pollution.

The research results were published in Applied Microbiology and Biotechnology, entitled "Influence of metals and metalloids on the composition and fluorescence quenching of the extracellular polymeric substances produced by the polymorphic fungus Aureobasidium pullulans".

Article link: https://link.springer.com/article/10.1007/s00253-020-10732-7 

Changes in the biomass and EPS production from Aureobasidium pullulans under different metal(liod)s stress