Optimization of DNA extraction from the Algerian traditional date’s product “Btana”

Btana is traditional preservation method that can sustain date’s supply during many years in comparaison to the commercial storage methods. However no scientific informations are available about biological factors that contribute to the successful of this method. Bacterial communities are a major key in preservation of many foods. Culture independent techniques are the most powerful tools to enhance bacterial diversity studies, but their efficiencies start with DNA extraction step. Therefore we have studied 3 protocols of DNA extraction from 11 Btana samples to evaluate their yield in total microbial DNA recovery. Protocols were based on a commercial kit DNeasy (QIAGEN, Germany) and two modified CTAB extraction methods (combined CTAB-DNeasy protocol, modified CTAB protocol) using polyvinyl pyrrolidone (PVP) and treatment with high salt solution (5M NaCl). Protocols were compared for quantity of DNA extracted using NanoDrop® ND-1000 Spectrophotometer and quality of DNA by 260/280 nm absorption ratio. The total extracted DNA was cheeked by PCR amplification of the 16S rRNA and visualized by electrophoresis on agarose gel (0.8%). Results showed that CTAB modified method provide the best DNA yield; however purification with NucleoSpin® Kit (Clontech, UK) was mostly needed for amplifying the DNA template. DNeasy kit protocol gave an amplified high quality DNA, but poor yields were obtained from date samples.