This System Is Mainly Designed To Extract Plasmid DNA From Gram(-) Bacteria Such As E. Coli. Gram(+) Bacteria Have Thicker Cell Wall So Cell Lysis Buffers Provided In The Kit Does Not Lyse Them Readily. However, Extraction Of Plasmid DNA From Gram(+) Bacteria Can Still Be Achieved With Additional Treatment. After Resuspending The Pelleted Bacterial Cells In MX1 Buffer, Add Lysozyme To Give A Final Concentration Of 3 To 5 Mg/Ml. Incubate The Suspension At 37˚C For 30-60 Minutes (Or For A Shorter Time When Use 5 Mg/Ml Lysozyme). This Treatment Weakens The Cell Wall Of The Gram(+) Bacteria. Then Add MX2, And Follow The Rest Of The Protocol. For Certain Gram(+) Bacteria With Thin Cell Wall, Such As Lactobacillus, Applying Of Double Amount Of MX1, MX2, And MX3 Buffer May Have Been Enough To Lyse The Cells. Yet, We Still Recommend Treating Gram(+) Bacteria With Lysozyme To Facilitate Cell Lysis.