diff --git a/workflow/scripts/adapter_removal_paired.py b/workflow/scripts/adapter_removal_paired.py
index 9db04ea0..c7613ba4 100755
--- a/workflow/scripts/adapter_removal_paired.py
+++ b/workflow/scripts/adapter_removal_paired.py
@@ -28,7 +28,7 @@
                 "--cores",
                 str(snakemake.threads),
             ]
-            args += snakemake.config["qc"]["cutadapt_opts"].split(" ")
+            args += snakemake.config["qc"]["cutadapt_opts"].split(" ") if snakemake.config["qc"]["cutadapt_opts"] else []
             args += fwd_adapter_str.split(" ")
             args += rev_adapter_str.split(" ")
             args += [
diff --git a/workflow/scripts/adapter_removal_unpaired.py b/workflow/scripts/adapter_removal_unpaired.py
index 221b866f..b28bcc64 100755
--- a/workflow/scripts/adapter_removal_unpaired.py
+++ b/workflow/scripts/adapter_removal_unpaired.py
@@ -27,7 +27,7 @@
                 "--cores",
                 str(snakemake.threads),
             ]
-            args += snakemake.config["qc"]["cutadapt_opts"].split(" ")
+            args += snakemake.config["qc"]["cutadapt_opts"].split(" ") if snakemake.config["qc"]["cutadapt_opts"] else []
             args += fwd_adapter_str.split(" ")
             args += rev_adapter_str.split(" ")
             args += [