11
Section 7
Troubleshooting Guide
Problem
Possible Cause
Possible Solution
Low plasmid yields
Low copy number
Use high copy number
plasmid
constructs
Poor plasmid
Inoculate large-scale
propagation in culture
cultures with overnight
cultures generated from
fresh colonies grown on
a selective medium
Determine optimum
growth and plasmid
propagation times for
culture depending upon
host, broth, etc.
Check age and
concentration of
antibiotic
Excessive amount of
Determine OD
600
of
bacteria processed
culture and reduce
OD•ml of bacteria
processed to ensure
efficient lysis
Incomplete resuspension
Ensure that the bacterial
of bacteria pellet
pellet is completely
resuspended prior to
addition of lysis solution
Excessive drying of
See protocol. Do not
column membranes
exceed 1 min
prior to elution
centrifugation.
Insufficient ethanol
Check that correct
added to wash solution
amount was added
concentrate
