diff --git a/scripts/ems/support/interpolate-lm.perl b/scripts/ems/support/interpolate-lm.perl
index 155829556..6d6f3fdd1 100755
--- a/scripts/ems/support/interpolate-lm.perl
+++ b/scripts/ems/support/interpolate-lm.perl
@@ -135,7 +135,7 @@ sub interpolate {
   die "Failed to mix models: $mixerr" if $mixexitcode != 0;
   my $mix = $mixout;
   `rm $tmp/iplm.$$.*`;
-  $mix =~ /best lambda \(([\d\. ]+)\)/ || die("ERROR: computing lambdas failed: $mix");
+  $mix =~ /best lambda \(([\d\. e-]+)\)/ || die("ERROR: computing lambdas failed: $mix");
   my @LAMBDA = split(/ /,$1);
 
   # create new language model