diff --git a/common/python/nomadcore/md_data_access/MDDataAccess.py b/common/python/nomadcore/md_data_access/MDDataAccess.py
index 4e14ba8f6e965216e02233974a21827de145b96f..d2104024f66f9ef3cdeb767c58dd73e81af00730 100644
--- a/common/python/nomadcore/md_data_access/MDDataAccess.py
+++ b/common/python/nomadcore/md_data_access/MDDataAccess.py
@@ -3653,7 +3653,7 @@ class MDDataAccess(object):
 
         return topology
 
-    def load_mdanalysis_topology(self, file_format):
+    def load_mdanalysis_topology(self, file_format=None):
         """ Support level for MDAnalysis package
 
         If filename is given, we try loading the format, if its a trajectory
@@ -3666,7 +3666,10 @@ class MDDataAccess(object):
 
         topology = None
         universe = None
-        fileformat = re.sub('[.]', '', file_format)
+        if file_format:
+            fileformat = re.sub('[.]', '', file_format)
+        else:
+            fileformat = file_format
         top=self.topofile
         if top:
             try: