diff --git a/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/sx/pangaea/PangaeaUtils.scala b/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/sx/pangaea/PangaeaUtils.scala
index a8a737c23a..f62267e944 100644
--- a/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/sx/pangaea/PangaeaUtils.scala
+++ b/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/sx/pangaea/PangaeaUtils.scala
@@ -26,7 +26,7 @@ object PangaeaUtils {
     val s:String =  s"${new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS")format(d)}Z"
 
     val ds = (json \ "internal-datestamp").extractOrElse[String](s)
-    val identifier= (json \ "metadatalink").extractOrElse[String]()
+    val identifier= (json \ "metadatalink").extractOrElse[String]("")
     val xml= (json \ "xml").extract[String]
     PangaeaDataModel(ds, identifier,xml)
   }