Biomachining in manufacturing: mechanisms, processes, applications and future perspectives

Biomachining (BM) is an emerging bio-assisted manufacturing approach that uses microbial metabolism and bioelectrochemical reactions to remove material under mild conditions. Due to its low mechanical loading and limited thermal effects, BM has potential in low-damage microfabrication, surface functionalization, microfluidic mold fabrication, abrasive tool dressing, and functional device modification. This review critically summarizes BM with respect to removal mechanisms, process technologies, modeling and optimization strategies, manufacturing applications, and engineering challenges. The biological and electrochemical mechanisms of BM are discussed first, followed by conventional and hybrid BM processes and their comparison with conventional and non-conventional machining technologies. Current applications are reviewed with emphasis on the gap between laboratory demonstrations and scalable industrial implementation. Major challenges include low removal efficiency, limited dimensional accuracy, unstable microbial activity, weak process controllability, contamination risk, waste treatment, and biosafety management. Future development should focus on standardized evaluation, microbial stability control, mechanism-data fusion modeling, hybrid process intensification, and dedicated equipment. Machine learning-assisted prediction, Internet of Things-enabled monitoring, digital twin-based closed-loop control, and sustainability/techno-economic validation are also important for moving BM toward controllable and scalable manufacturing.