Upon following the Plaque Amplification for Elisa or Sequencing procedure of Ph.D. Phage Display Libraries on p.22 of the instruction manual, and then applying the Rapid Purification of Sequencing Templates procedure on p.23, I keep on obtaining low sample DNA concentrations even though I load 5 ul of sample onto 0.8% agarose gel. I tried upscaling the Plaque Amplification procedure by incubating the plaques in 5 ml and 10 ml diluted Ecoli culture tubes instead of 1 ml and I also used 1-1.4 ml phage-containing supernatant instead of 0.5 ml in the Rapid Purification procedure; the gel electrophoresis bands were brighter but still of low concentration. Is there a way I can significantly increase the concentration of isolated DNA?

P.S: I PCR’d my products using Taq DNA polymerase and still faced low concentration problems even after the addition of 10 ul samples (~200bp) in 2% Agarose gels.