Heavy metal tolerance of filamentous fungal strains isolated from soil irrigated with industrial wastewater

Abstract

In the present study the tolerance level of different fungi (Aspergil lus flavus, Aspergillus niger, Aspergillus versicolor, Scopulariop sis sp., Curvularia sp., Helminthosporium sp., Humicola grisea sp., Nannizzia sp., and Fusarium sp.) were investigated towards heavy metals which were isolated from contaminated peri-urban agricultural soils of Faisalabad.The concentration of heavy metals in soil is determined by using atomic absorption spectrophotometer. The degree of tolerance of fungi was measured by minimum inhibitory concentration in the presence of different concentrations of heavy metals (Cr and Pb) and compared to control sample. Tolerance analysis depicts that growth rate of fungal isolates decreased with increase in concentrations and few isolates are tolerant, some are moderately tolerant and some are sensitive towards metal concentrations of Cr and Pb. Most of the isolates were tolerant to metals. Among all tested fungal strains, few isolates of Aspergillus flavus and Aspergillus niger, Fusarium were tolerant to Cr and Pb. Thus these tolerant isolates can be used for the purpose of bioremediation in future.

Heavy metal concentration and the occurrence of selected microorganisms in soils of a steelworks area in Poland

“…In the discussed site very high concentrations of cadmium, lead and zinc were recorded and these elements are considered to have strong inhibitory effect on soil microorganisms (Kabata-Pendias and Pendias 1999, Wyszkowska et al 2013). The fact that of all examined microbial groups, fungi seemed to be the least affected by the high concentrations of heavy metals is however not unprecedented, as fungi together with yeasts, are considered to be the most tolerant and thus versatile group of soil microorganisms (Iram et al 2013). Fungal cell wall contains different materials which proved to be efficient metal biosorbents (Gavrilescu 2004).…”

Metallophilic fungi research: an alternative for its use in the bioremediation of hexavalent chromium

“…For the species with the Fusarium genus, the tolerance of Cr(VI) has been reported to be 1000, 1300, to 5000 lg/ mL (Iram et al 2012;Ezzouhri et al 2009;Zafar et al 2007), e.g., F. solani has a tolerance that is reported to be 1000 lg/mL (Sen and Dastidar 2011). On the other hand, Penicillium species has been reported to have a tolerance of approximately 1040-7000 mg/mL of total chromium (Zafar et al 2007).…”

“…Aspergillus has been reported to have a tolerance at 200 lg/mL (Ahmad et al 2005), 600 lg/mL (Bennett et al 2013), 650 lg/mL (Ezzouhri et al 2009), with 5000 lg/mL for total chromium (Ahmad et al 2006). Others species, such as A. flavus, have had a Cr(VI)-tolerance of 600 lg/mL (Bennett et al 2013), with 800 lg/ mL for total chromium (Iram et al 2012); A. niger had 600 lg/mL (Bennett el al. 2013) and 1000 lg/mL for total chromium (Iram et al 2012); and A. versicolor reported to have a tolerance of 1000 lg/mL for Cr(VI) and total chromium (Das et al 2008;Iram et al 2012).…”

“…(Ahmad et al 2005) were obtained from crop fields watered with wastewater and industrial effluents and contained 92.5 up to 116.5 mg/g of total chromium; Aspergillus flavus, Humicola grisea, Fusarium sp., Nannizzia sp., Helminthosporium sp., Curvularia sp., Aspergillus niger, Aspergillus versicolor, and Scopulariopsis sp. were isolated by Iram et al (2012) from soil watered by industrial effluents with a 76.9 mg/kg of total chromium concentration; Penicillium sp. was the main fungi isolated from water and sediment of industrial and tannery effluent, also municipal industrial wastewater, and contained (85.6, 369, 36.1) lg/kg in sediment and (1.06, 2.1, 0.14) mg/L in water, respectively.…”

Screening and Identification of Heavy Metal-Tolerant Endophytic Fungi Lasiodiplodia Theobromae From Boswellia Ovalifoliolata an Endemic Plant of Tirumala Hills

“…All ten isolates showed resistance Co and Zn up to 600 ppm but only HEF3 isolate showed resistance to all four heavy metals Co, Cd, Cu and Zn at 600 ppm. The difference in metal tolerance may be due to the presence of various strategies of resistance mechanism exhibited by the fungi [23,24]. Most studies have been undertaken on filamentous fungal strains and mostly members from the genera Aspergillus, Fusarium, Humicola, and Nannizzia have been reported to possess resistance against heavy metals [13,23,25].…”