ScienceAsia 27 (2001) : 083-092 |doi: 10.2306/scienceasia1513-1874.2001.27.083

Selection of Fungi Capable of Removing Toxic Arsenic Compounds from Liquid Medium

Pornsawan Visoottiviseth^* and Nootra Panviroj

ABSTRACT: Thirty eight fungal isolates that grew in 700 mg l^-1 of either arsenite or arsenate medium were isolated from soil samples collected from arsenic-polluted areas in Ron Phibun District, Nakhon Si Thammarat Province, Thailand. Out of these, the fungal isolate (RRMT2-40I) was the most efficient at removing arsenite/arsenate from potato dextrose broth. This fungus, identified as Penicillium sp., grew best in growth medium with a pH of 5.0 or 7.0 at 27 ^oC, reaching the stationary growth phase within 4 days. Its growth was slightly affected by arsenite/arsenate concentrations of 1000 mg l^-1 in the medium, but lower concentrations (10 and 100 mg l^-1 ) had no effect. Arsenic uptake exhibited a peak and turning point at the stationary growth phase. During this phase, arsenic was excreted from the fungal cells. Arsenic removal depended on culture age and cell viability since there was no arsenite/arsenate removal when the cells were killed by autoclaving.

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Biology Department, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400,
Thailand.

* Corresponding author, E-mail: scpvi@mahidol.ac.th

Received 15 Nov 2000, Accepted 30 Mar 2001