Eco-Microbiology: A Frugal-Circular Framework for Biosafe, Low-Cost Practical Microbiology in Secondary Education.

Microbiology offers valuable experiential learning, but secondary-school practice is limited by cost, infrastructure, biosafety and teacher confidence. This review presents a framework for sustainable, frugal-circular and pedagogically rigorous microbiology in resource-limited settings, positioning frugality not only as low-cost provision but as a teachable behavioural principle of minimal resource extraction, maximal conservation and upstream waste prevention. It shows how to replace standard equipment and consumables with accessible, reusable alternatives (e.g., domestic pressure cookers, improvised incubators, everyday glassware) while maintaining equity, scientific rigour and clear biosafety boundaries. Circular science education is operationalised through guidance on constructing essential tools, preparing culture media from household ingredients and choosing safer, food-associated microbial sources (fermented foods, probiotics) appropriate for biosafety level 1 teaching. When environmental materials are used, activities are limited to teacher-led, sealed observation and the precautionary rule 'unknown = potentially pathogenic'. The paper provides protocols for sterilisation, disinfection and waste management, including an end-of-session workflow for reliable culture inactivation before disposal. An implementation guide and checklist translate these principles into classroom routines, with a model experiment, assessment ideas and management strategies. The framework demonstrates that inclusive, environmentally responsible microbiology is feasible across diverse school contexts and can strengthen scientific citizenship by linking laboratory practice to global stewardship concepts, including frugality.