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

Background: 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. Objectives: 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. Materials and Methods: DNA quantity and quality was determined by spectrophotometry, agarose gel electrophoresis and polymerase chain reaction (PCR). Results: 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. Conclusions: We suggest this protocol for effective and inexpensive DNA isolation from L. casei for downstream biological processes such as PCR.