3.3. Culture-independent assessment of archaeal diversity in food-grade salts
All culture-based techniques have the important drawback that a medium with a define composition may not suit the requirement of all species. To overcome this constraint, a metagenomic analysis was performed to provide complementary information about the archaeal diversity in food-grade salts. A preliminary optimization of the DNA
extraction stepwas performed. Themost efficient extractionmethod involved the dissolution of food-grade salt in SW 12%, cell concentration on a 0.2 μm filter, lysis with a solution containing SDS 10% and proteinase K, followed by the DNA purification with phenol/chloroform and
precipitation with isopentanol (data not shown). This method successfully
achieved 16S rRNA geneamplification for eight food-grade salts: La
Baleine coarse, Lac Rose, Palm Island black, Camargue, Dead Sea, Hâlen
Môn, Maras and Black Sea salts. The PowerSoil® DNA isolation kit