Methods for extraction of microorganism DNAfrom glacier surface snow

In order to thoroughly investigate the diversity of glacier microorganisms, four DNA extraction methods with different lysis patternswere tested and two screened methods (the Bosshard-Bano method and the Zhou method) were optimized for the most effectiveform of the filter membrane (cut vs. uncut), the DNA extraction method, and the precipitation method. The two optimizedmethods were then compared with the commercial Mo-Bio DNA extraction kit, and the results showed that the kit was generallysuitable for extraction of microorganism DNA from glacier surface snow. Procedurally, it was found that a modified Bosshard-Bano method (i.e., cutting the filter membrane into pieces, using a specific lysis pattern [lysozyme (5 mg/mL)-protease K(1 mg/mL)-CTAB (1%)-SDS (1%)], performing the extraction only once by chloroform-isoamyl alcohol (24:1), and conductingDNA precipitation by pure ethanol) was also an effective and less expensive method for extraction of microorganism DNA fromglacier surface snow.