diff --git a/src/nf_modules/concatenate/main.nf b/src/nf_modules/concatenate/main.nf
index 741d0431ba26d59446fc78140e68722b4ad508db..ab1d15732edc91bd4b4c350b0011b92ab5ebea06 100755
--- a/src/nf_modules/concatenate/main.nf
+++ b/src/nf_modules/concatenate/main.nf
@@ -19,7 +19,6 @@ process concatenate {
 
     script:
 """
-zcat ${fastq}/*.fastq.gz > merged.fastq
-gzip --quiet merged.fastq
+cat ${fastq}/*.fastq.gz > merged.fastq.gz
 """
 }
\ No newline at end of file