Taguchi approach significantly increases bioremediation process efficiency: a case study with Hg (II) removal by...

Optimization of process parameters for mercury removal by an Hg (II)-reducing Pseudomonas aeruginosa strain.

A strain of Ps. aeruginosa was found to reduce 10 mg l(-1) Hg (II) to Hg0 with 70% efficiency in 24 h. To optimize process performance, a statistical tool--Taguchi design of experiments (DOE)--was used to carry out 18 well-defined experiments (L18 Orthogonal array) with eight variable parameters (viz. agitation, temperature, pH, carbon source, medium volume: flask volume ratio and concentrations of Hg (II), ammonium sulfate and yeast extract). When data obtained were analyzed using specialized software for Taguchi design, Qualitek-4 (Nutek Inc., MI, USA), Hg (II) reduction efficiency was predicted to be 95% in 24 h under the optimized process parameters (also suggested by the software). In the validation experiment, Hg (II) removal of 99.29% in 24 h was indeed obtained.

Using Taguchi DOE, Hg (II) reduction (and hence its removal) using Ps. aeruginosa could be improved by 29.3%.

Taguchi approach could be employed as an efficient and time-saving strategy for parameter optimization in bioremediation processes.