Mini-prep yields almost no plasmid DNA (Plasmid Mini-prep)

Question

Accepted Answer

Eluate DNA concentration is very low; diagnostic digest and gel show no detectable target band. Common causes: 1) Culture volume was too small or growth time too short 2) Cell lysis was incomplete — plasmid not released 3) Heavy losses during the column wash / elution steps 4) Plasmid copy number is intrinsically low or unstable Solutions: 1) Increase culture volume and extend growth (LB + antibiotic, overnight 16–18 h) 2) Lyse fully — pipette mix gently after adding lysis buffer; avoid clumps; extend if needed 3) Follow the kit protocol precisely (skip air-drying issues, elute with warm buffer) 4) Use a high-copy backbone (e.g. pUC ori) or optimize growth conditions