Enhancement of nickel laterite ore bioleaching by Burkholderia sp. using a factorial design

Interest in low-grade Ni-laterite ores has increased in recent years; however, the laterite process has proven technically difficult and costly, and the development of alternative low-cost biotechnologies for Ni solubilization has been encouraged. In this context, for the first time, a sample of Brazilian Ni-laterite ore was subjected to microbial bioleaching using a heterotrophic Burkholderia sp. strain. Experiments were performed in a 23 two-level full factorial design by determining the influence of glucose concentration (5–15%, w/v), Ni-laterite ore concentration (0.25–0.75%, w/v), and cultivation period (14–42 days) on Ni solubilization. The variable more important for Ni-laterite bioleaching was the glucose concentration (x1). Bioleaching batch experiments demonstrated that about 87% Ni (7.5 mg Ni/g ore) were solubilized by Burkholderia sp. after 42 days. This study's significance is that it has opened up an opportunity for the potential application of potassium-solubilizing bacterial strains to process low-grade Ni-laterite ores.