I've been wanting to analyze gut microbial community in Abalone. Two research I've read (Huang et al, 2010 DOI:10.1111/j.1365-2109.2010.02577.x ; Lee et al, 2016 DOI:10.1016/j.ijfoodmicro.2016.06.032) used SDS-phenol metagenomic DNA extraction method, but as my understanding, done with different steps.

Different steps used in those studies e.g.

1. The former used freeze thaw cycles (-70 C & 65 C) after adding lysozyme, proteinase K, and SDS. The latter only incubated in 65 C.

2. RNase A was added after precipitation using ammonium citrate in the former, and the latter one RNase A was added before precipitation.

3. Concentration of SDS used in the former was 1%, and the latter was 10%

Does these two works? Are there any effect on metagenomic DNA after extraction? Thank you