diff --git a/bio/seqkit/wrapper.py b/bio/seqkit/wrapper.py
index a1bc7f38fa..16dd34aae9 100644
--- a/bio/seqkit/wrapper.py
+++ b/bio/seqkit/wrapper.py
@@ -38,9 +38,9 @@
 
 
 if snakemake.params.get("out_bgzip"):
-    input = input + " | bgzip --threads {snakemake.threads} > {snakemake.output[0]}"
+    input = input + f" | bgzip --threads {snakemake.threads} > {snakemake.output[0]}"
 else:
-    input = "--out-file {snakemake.output[0]} " + input
+    input = f"--out-file {snakemake.output[0]} " + input
 
 shell(
     "(seqkit {snakemake.params.command}"