Experimental studies on biomachining process using novel Thiobacillus novellus microorganism — a comparative study

This paper discusses the importance and effect of three different microorganisms used in biomachining process. The aluminum alloy is used as a work sample for performing machining operation using Thiobacillus novellus ( Th. novellus ), Acidithiobacillus thiooxidans ( At. thiooxidans ), and Acidithiobacillus ferrooxidans ( At. ferrooxidans ). The pH and cell concentration of the biomachining process is kept constant for the designed experiment. The other parameters such as shaking rate, temperature, and microorganisms are kept at three levels. Experimental studies were conducted based on the L 27 orthogonal array with three levels and parameters. Specific material removal rate (SMRR), material removal rate (MRR), and surface roughness ( R a ) were measured and compared for three different microorganisms. The experimental results revealed that shaking rate plays a vital role in increasing the SMRR and MRR. Among all, the performance of the At. ferrooxidans is superior than the other two microorganisms in terms of SMRR and MRR. Further, the effect of initial roughness of the work sample on machining process is also discussed. It is observed that initial surface roughness of the work sample significantly affects the SMRR and MRR.