Improved method for the production of M13 phage and single-stranded DNA for DNA sequencing.

An improved method is described for the efficient production of M13 phage and M13 single-stranded (ss)DNA in a relatively short time period. Infection of E. coli (F') cells with as few as 5 phage particles can yield 10(12) phage particles/mL in 3 hours if the cells are grown in LB broth or SOB broth supplemented with about 5 mM Mg2+. The method tolerates large variations in the initial multiplicity of infection (5-5000 phage per 5 x 10(7) cells) and still yields about 10(12) phage particles/mL. These amounts are sufficient to purify 10-15 micrograms of ssDNA and to carry out at least 10-15 DNA sequencing reactions.