An Efficient DNA Extraction Method for Lactobacillus casei, a Difficult-to-Lyse Bacterium

There are several protocols to extract DNA from Lactobacillus spp. In the case of L. casei it is harder because of its especial and thick cell wall. In this study, nine DNA extraction protocols (by lysozyme treatment) were evaluated and compared in two categories (traditional and kit-based protocols) and an improved method was presented. DNA quantity and quality was determined by spectrophotometry, agarose gel electrophoresis and polymerase chain reaction (PCR). The results revealed that the yield of extracted DNA differed by each protocol (5.8 - 17.1 μg/100 μL), but provided appropriate DNA for PCR amplification. The modified protocol offered the best total DNA extraction method when both quality (DNA purity; 1.54 μg) and quantity (DNA yield; 17.1 μg) were considered. We suggest this protocol for effective and inexpensive DNA isolation from L. casei for downstream biological processes such as PCR.