ISOLATION OF A LIGNOLYTIC FACULTATIVE ANAEROBE FROM FORMER GOLDMINE IN HOMESTAKE, LEAD, SOUTH DAKOTA

摘要

The former goldmine at Homestake, Lead, South Dakota had wooden support infrastructure.Some of the wooden logs have been decomposing in the water logged soil since closing of themine in 2001. The hot (between 40°C-43°C) and humid mine conditions devoid of sunlightmimic the environment in a rain forest and has led to rapid decomposition of the wooden logs.Soil underneath decomposing logs was collected to screen for lignin degrading anaerobes.Microflora from the soil was enriched on minimal media containing Kraft lignin as sole carbonsource. The soil cultures were incubated under anaerobic conditions without shaking at 43°C.After 5 successive transfers in 60 days, a gram negative lignolytic bacterial species was isolated.The bacteria were found to completely degrade Kraft lignin in 76 days. The fermentationproducts formed were identified by GC-MS. Succinic acid was identified as one of theproducts formed within 48 hrs of inoculation. The biochemical characteristics and 16S rRNAsequence analysis identified the lignolytic microbe as a strain from the Enterobacter cloacae .