Factors affecting toxic lead(Ii) ion bioremediation by Fusarium equiseti isolated from the mangrove soil environment of southeast Borneo

Aims: Electronic waste (e-waste) is an inorganic pollutant which causes a serious environmental problem since it contains toxic heavy metals, which cannot be removed from contaminated sites easily. The use of biomaterials for removing heavy metals from contaminated soil and wastewater has emerged as a potential alternative method to the conventional techniques. The present study were aimed to isolate efficient lead tolerant fungi from mangrove soil environment and measure its capability for lead removal from aqueous solution. Methodology and results: Lead tolerant fungal strains were isolated from soil samples using PDA (Potato Dextrose Agar) supplemented with varied concentrations of lead ions (100-500 mg/L). The most tolerant fungal strain was successfully isolated and identified molecularly as Fusarium equiseti KR706303. The isolated fungus was used for biosorption studies using Potato dextrose broth (PDB) supplemented with lead ions. The effects of pH, temperature, initial metal concentration, biomass dose and age, agitation and contact time to the Pb(II) removal efficiency were monitored in the study. The results showed that the optimal parameters for the removal of lead ions such as heavy metal concentration and pH were 300 mg/L, with a maximum Pb(II) adsorption of 97.9% observed at pH 4 and temperature of 30 °C during the batch biosorption experiments. The optimal parameters for biomass dose, agitation speed, contact time and biomass age were observed at 0.04 g, 150 rpm, 60 min and fifth day; respectively. Conclusion, significance and impact of study: The observation in this study revealed that the biomass of the isolated Fusarium equiseti KR706303 has the potential to be used as a biosorbent for heavy metal particularly Pb(II) removal from the contaminated sites. The technology is simple, efficient, cost effective and environmental friendly.

Isolation and identification of pathogen causing stem blight disease on Abelmoschus manihot (L.) Medic / 中国生化药物杂志

Objective To isolation and identify the pathogen of stem blight of Malvaceae.Methods The stems were collected from stem blight-diseased plants (J) and healthy ones (W) of Abelmoschus manihot (L.) Medic.in Yixing City of Jiangsu Province then cultured to isolate newborn mycelium.The pathogen isolated but unidentified were inoculated in stems of healthy plants of Abelmoschus manihot ( L.) Medic.and pathogenicity was verified.Finally, the pathogenic specie( s) was or were identified by morphological characteristic, rDNA-ITS analysis and polymerase chain reaction (PCR) method.Results The same fungus were excluded which were the same species in J and W, the three fungus of J2, J5 and J6 were acquired.J5 was preliminarily identified to have pathogenicity and it was Fusarium equiseti under the microscope.The genome DNA of J5 was amplified to a length of 524bp, and homology highly with Fusarium equiseti (100%).Conclusion The pathogen was identified as Fusarium equiseti.