diff --git a/common/lib/xmodule/xmodule/course_metadata_utils.py b/common/lib/xmodule/xmodule/course_metadata_utils.py
index faa43f37b3..c862356513 100644
--- a/common/lib/xmodule/xmodule/course_metadata_utils.py
+++ b/common/lib/xmodule/xmodule/course_metadata_utils.py
@@ -66,8 +66,9 @@ def clean_course_key(course_key, padding_char):
         padding_char (str): Character used for padding at end of the encoded
             string. The standard value for this is '='.
     """
+    encoded = b32encode(six.text_type(course_key).encode('utf8')).decode('utf8')
     return "course_{}".format(
-        b32encode(six.text_type(course_key)).replace('=', padding_char)
+        encoded.replace('=', padding_char)
     )