use strict;
use warnings;
open my $fh, '<', 'kegg_pathway_title.txt' or die $!;
my %dict =  map { chomp; split ' ', $_, 2 } <$fh>;
my $re = join '|', keys %dict;
open $fh, '<', 'Orthogroups_3.csv' or die $!;
while (<$fh>) {
  s/($re)/$dict{$1}/g;
  print;
}

##</code><code>##

next if $. < 2;