I have been trying to extract DNA with no success. I have used following methods

1. PCI method with and without bead beating

2. kit methods qiagen, himedia

3. interchange of reagents

4. cold and heat shock treatments

I have got DNA from PCI method BUT the ratio of 260/280 is 1.4 or less and the ratio of 260/230 is either more than 1.5 or for few samples it is less than 0.8

The salinity is more than 0.8 ppt and tds is more than 500mg/l

I have to send these samples for amplicon sequencing.