diff --git a/src/nf_modules/Bowtie/bowtie.nf b/src/nf_modules/Bowtie/bowtie.nf
index d51ec4d99b0aa734b990803fb3432c5377b60547..ff7ad04cc0639480754ce8ba8c3ba33d90540b83 100644
--- a/src/nf_modules/Bowtie/bowtie.nf
+++ b/src/nf_modules/Bowtie/bowtie.nf
@@ -65,7 +65,7 @@ process mapping_fastq {
 
   input:
   set pair_id, file(reads) from fastq_files
-  file index from index_files.toList()
+  file index from index_files.collect()
 
   output:
   file "*.bam" into bam_files
@@ -117,7 +117,7 @@ process mapping_fastq {
 
   input:
   file reads from fastq_files
-  file index from index_files.toList()
+  file index from index_files.collect()
 
   output:
   file "*.bam" into bam_files
diff --git a/src/nf_modules/Bowtie/tests/mapping_paired.nf b/src/nf_modules/Bowtie/tests/mapping_paired.nf
index 6ea2d70ad18ec6273fe87e8d8f7d34f41f2b82ac..600e295cc5be7935f88fdd72d4625e78afe1373a 100644
--- a/src/nf_modules/Bowtie/tests/mapping_paired.nf
+++ b/src/nf_modules/Bowtie/tests/mapping_paired.nf
@@ -20,7 +20,7 @@ process mapping_fastq {
 
   input:
   set pair_id, file(reads) from fastq_files
-  file index from index_files.toList()
+  file index from index_files.collect()
 
   output:
   file "*.bam" into bam_files
diff --git a/src/nf_modules/Bowtie/tests/mapping_single.nf b/src/nf_modules/Bowtie/tests/mapping_single.nf
index 551b90cedcfc4dfbf13fb619b83b01b3006b1067..ad94f5b6e67911812611b4190ead3832a57162b9 100644
--- a/src/nf_modules/Bowtie/tests/mapping_single.nf
+++ b/src/nf_modules/Bowtie/tests/mapping_single.nf
@@ -19,7 +19,7 @@ process mapping_fastq {
 
   input:
   file reads from fastq_files
-  file index from index_files.toList()
+  file index from index_files.collect()
 
   output:
   file "*.bam" into bam_files