A low OD260/230 is often caused by chaotrophic salts used in the kit to denature and bind the dna to the membrane. The high absorbance of the salts at 230 causes a low ratio. You can try purifying less material or just add an extra wash step of the dna on the column before eluting. If these fail then precipitating the purified dna with salt/alcohol followed by a wash of the dna peller with 70% alcohol will remove salts and give an improved OD260/230

You can get an increased yield by adding the elution buffer at 70c and leaving it on the membrane for twice as long as the kit recommends.

You didn't specify which part of the user manual you followed to make the genomic DNA extraction.

But if I supposed  you used part "3.F. Isolating Genomic DNA from Yeast" on page 13 of the user manual :

At the step 18 : "Add 1.5μl of RNase Solution to the purified DNA sample. Vortex the sample for 1 second. Centrifuge briefly in a microcentrifuge for 5 seconds to collect the liquid and incubate at 37°C for 15 minutes"

The result of this step is that the nuclear RNAs are digested by RNase, but the nucleotides that come from this digestion still remain. If you haven't removed them, then after step 18 you get a mixture of genomic DNA with RNA nucleotides.

However, nucleotides absorb UV rays, which falsifies the DNA assay.

If this is indeed what happens, then a DNA purification step must be added in order to remove the nucleotides - like a "on column DNA purification" - or a "differential precipitation" or a "Solid Phase Reversible Immobilization Methodology" and so on ...

Good luck

Hello, use the benzyl chloride method for DNA extraction.