Actinobacteria isolates from tin tailings and forest soil for bioremediation of heavy metals

The aim of this study was to screen actinobacteria isolated from bidor tin tailings for heavy metal tolerance as an early exploration into their bioremediation capabilities. as a comparison,isolates from forest soil in pasoh were also studied for heavy metal tolerance. at the highest test concentration,rapid metal tolerance screening showed that the numbers of hg2+,cd2+ and cu2+ tolerant isolates were less than 7% of the total isolates screened for both sites. more than 10% of total isolates screened from both sites showed tolerance to pb2+,as3+ and zn2+. the number of ni2+ tolerant isolates was significantly higher for bidor (12.6%) compared with pasoh (6.6%). metal toxicity assay carried out on tolerant isolates from bidor showed that the final metal concentrations supporting actinobacteria growth were 138.9 mmol l -1 for ni2+,43.2 mmol l-1 for pb 2+,21.8 mmol l-1 for cd2+,0.8 mmol l -1 for hg2+,182 mmol l-1 for as3+ and 14.1 mmol l-1 for cu2+. for pasoh isolates,tolerance was observed at 21.8 mmol l-1 for cd2+ and 182 mmol l -1 for as3+. compared with rapid metal tolerance screening,metal toxicity assay clearly showed that metal tolerant isolates from bidor were capable of tolerating heavy metals at a higher concentration compared with pasoh isolates. isolates ty046-021 and ty046-078,which showed multimetal tolerance to as3+,pb2+ and ni2+ and ty046-017,the only hg2+ tolerant isolate from bidor,should be further studied for heavy metal uptake and removal. © 2014 forest research institute malaysia.