diff --git a/tests/nextflow.config b/tests/nextflow.config
index 3aa1b95c..54484af3 100644
--- a/tests/nextflow.config
+++ b/tests/nextflow.config
@@ -1,4 +1,4 @@
 env {
-    NCBI_EMAIL = "${NCBI_EMAIL}"
-    NCBI_KEY   = "${NCBI_KEY}"
+    NCBI_EMAIL = "$NCBI_EMAIL"
+    NCBI_KEY   = "$NCBI_KEY"
     }