Native Bacteria Isolated from Phosphate Deposits Reveal Efficient Metal Biosorption and Adhesion to Ore Particles

Mining and processing phosphate ore are among the essential branches of the economy in some developing countries, including Algeria. Conventional ore beneficiation methods can harm the environment by consuming tremendous amounts of water resources (during washing and flotation), potentially hazardous chemicals, and thermal energy. Mine water contains toxic metals that, when released, interfere with environmental functioning. Therefore, in line with environmental needs, conventional methods should be gradually replaced with safe biotechnological processes. This study aimed to investigate the biosorption and adhesion abilities of native microorganisms isolated from Djebel Onk ore (Algeria). The examined bacterial strains differed in their metal accumulation efficiency. The incubation of phosphate ore with the native strain Bacillus HK4 significantly increased the recovery of Mg and Cd (at pH 7, 8147.00 and 100.89 mu g/g(-1), respectively). The HK4 strain also revealed better adhesion to the ore particles than the reference strain of Bacillus subtilis. Thus, biosorption could be more effective when using the native HK4 strain, which can remove Cd and/or Mg over a pH 4-10 range. Moreover, concerning the unique adhesion capacity of HK4, the strain can be considered in the design of bioflotation methods, as well as in the development of an eco-friendly method of ore and post-flotation waste beneficiation.