Metagenomic sequenciong of Probiotic K
According to the manufacturers instructions, DNA library preparation was performed using the Nextera XT DNA sample preparation kit (Illumina, San Diego, CA, USA). First, one ng input DNA from each probiotic supplement was used for the library preparation underwent fragmentation, adapter ligation, and amplification. Then, Illumina libraries were pooled equimolarly, denatured, and diluted to a concentration of 1.5 pM. Next, DNA sequencing was performed on a NextSeq 550 instrument (Illumina) using a 2X 150 bp Output sequencing Kit together with a deliberate spike-in of 1% PhiX control library.