diff --git a/bifrost_chewbbaca/rule__blast_genecall.py b/bifrost_chewbbaca/rule__blast_genecall.py
index 668b096..731e2b9 100755
--- a/bifrost_chewbbaca/rule__blast_genecall.py
+++ b/bifrost_chewbbaca/rule__blast_genecall.py
@@ -36,7 +36,7 @@ def run_blastn_and_parse(query_fa, db, assembly_sequences,log):
     with subprocess.Popen(blastn_cmd, stdout=subprocess.PIPE, text=True, stderr=open(log.err_file, "w+")) as proc:
         stdout = proc.communicate()
         if proc.returncode != 0:
-            raise RuntimeError(f"Command {" ".join(blastn_cmd)} failed with code {proc.returncode}.\nCheck the logs in {log.err_file}")
+            raise RuntimeError(f"Command {' '.join(blastn_cmd)} failed with code {proc.returncode}.\nCheck the logs in {log.err_file}")
         for line in stdout:
             # Parse the BLAST output line into a dictionary
             cols = line.strip().split("\t")