Hello! I am currently trying to extract DNA environmental surface swab samples (store at -80C) and PTFE filters (air samples are collected on the filter). I could only get bare minimum (1/2ng/uL) or none DNA out of the samples. The kit I am using is from Qiagen (QIAamp DNA microbiome kit), and I cut the swab tips in the Eppendor tube before extraction. We would like to the go for sequencing afterwards but the DNA yield is just super low. Any suggestions regards to the extraction methods or alternative kits recommendations? Apparently, this kit is not good for frozen samples.