Ricerc@Sapienza

Arsenic, a common metalloid, is worldwide recognised as important toxic element for human beings and
living organisms (1,2). Natural processes as well as anthropogenic activities contribute to its diffusion and
occurrence in the environment (1,2). Fungi, as geoactive agents, can play very important geological roles in
several processes, including decomposition, biogeochemical cycling, element biotransformations, metal and
mineral transformations, bioweathering and soil formation (3,4). Fungi can tolerate and accumulate high
concentration of arsenic and for some species, biovolatilization via methylation was reported (5).
In this research, relationships between some soil saprotrophic microfungi and arsenic in relation to growth
responses and bioaccumulation were investigated. In particular, Absidia spinosa Lendn., Purpureocillium
lilacinum (Thom) Luangsa-ard, Houbraken, Hywel-Jones & Samson (formerly Paecilomyces lilacinus),
Metarhizium marquandii (Massee) Kepler, S.A. Rehner & Humber (formerly Paecilomyces marquandii) and
Cephalotrichum nanum (Ehrenb.) S. Hughes (formerly Doratomyces nanus), previously isolated from areas
with high natural As concentrations, were studied in two different cultural media, namely Malt Extract Agar
and Czapek-Dox Agar, and three different concentrations (10, 20 and 50 mg/L) of sodium arsenite (NaAsO2)
were tested. Metabolic responses and fungal tolerance to As have been investigated by tolerance indices,
namely Rt:Rc (%) and T.I. (%), based on growth data, diametric extension and dry weights, respectively.
Most of fungi resulted tolerant to all tested As concentrations, and values of tolerance indices varied
according to cultural media and As concentrations. pH medium after fungal growth was measured to study
pH variation and metabolic responses. As bioaccumulation in all fungi was observed with chemical analyses
by hydride generation atomic fluorescence spectrometry. As tolerance and bioaccumulation by fungi and
their metabolic responses shed further light in fungal geoactive roles in the environmental fate of As and
provide potential applications in bioremediation.
1) R. Singh, S. Singh, P. Parihar, V. P. Singh, S. M. Prasad (2015) Ecotox. Environ. Safe., 112, 247-270
2) A. Sarkar, B. Paul (2016) Chemosphere, 158, 37-49
3) A. Ceci, M. Kierans, S. Hillier, A. M. Persiani, G. M. Gadd (2015) Appl. Environ. Microbiol., 81, 4955-4964
4) A. Ceci, F. Pinzari, F. Russo, A. M. Persiani, G. M. Gadd (2019) Appl. Microb. Biotechnol., 103, 53-68
5) M. Singh, P.K. Srivastava, P.C. Verma, R.N. Kharwar, N. Singh, R.D. Tripathi (2015) J. Appl. Microb., 119, 1278-
1290