For the explanation of each column of sample_table, please refer to the soil_microb data document.
In tax_table, 'HMDB_ID' is the number of HMDB database. 'KEGG_ID' is the number of KEGG database.
sample_table: sample information table
otu_table: metabolites abundance table
tax_table: annotation table
data(soil_metab)R6 class object