Isolation and identification of an ammonia-producing copper leaching strain

An ammonia-producing strain isolated from Inner Mongolia in north China, which is capable of decomposing urea, was designated as strain JAT-1. Identification results show that this milky strain has a smooth and humid surface, and it is Gram-negative and rod-shaped in φ0.2-0.4 μm×1.5-2.0 μm. Based on the 16S rDNA sequencing and the phylogenetic tree, this strain was identified as Providencia Sp. By means of the analysis of growth characteristics, the optimal growth condition was achieved when the concentration of sodium citrate as a carbon source was 10 g·L^-1, the concentration of urea as a nitrogen source was 20 g·L^-1, the pH value was between 8.0 and 9.5, and the inoculum concentration was 20%. Alkaline copper ore bioleaching experiment in a shake flask with the ammonia-producing strain yielded a copper leaching efficiency of 42.38% in 144 h. This result indicates that this strain has the potential for leaching the alkaline copper ore.