diff --git a/markdown/extensions/abbr.py b/markdown/extensions/abbr.py
index 36c1d91c8..b35945fbb 100644
--- a/markdown/extensions/abbr.py
+++ b/markdown/extensions/abbr.py
@@ -121,7 +121,7 @@ def run(self, root: etree.Element) -> etree.Element | None:
         # Build and compile regex
         abbr_list = list(self.abbrs.keys())
         abbr_list.sort(key=len, reverse=True)
-        self.RE = re.compile(f"\\b(?:{ '|'.join(re.escape(key) for key in abbr_list) })\\b")
+        self.RE = re.compile(f"\\b(?:{'|'.join(re.escape(key) for key in abbr_list)})\\b")
         # Step through tree and modify on matches
         self.iter_element(root)
 
diff --git a/markdown/postprocessors.py b/markdown/postprocessors.py
index 7f5ede90c..48d366078 100644
--- a/markdown/postprocessors.py
+++ b/markdown/postprocessors.py
@@ -86,7 +86,7 @@ def substitute_match(m: re.Match[str]) -> str:
 
             if key not in replacements:
                 if key[3:-4] in replacements:
-                    return f'<p>{ replacements[key[3:-4]] }</p>'
+                    return f'<p>{replacements[key[3:-4]]}</p>'
                 else:
                     return key
 
@@ -94,7 +94,7 @@ def substitute_match(m: re.Match[str]) -> str:
 
         if replacements:
             base_placeholder = util.HTML_PLACEHOLDER % r'([0-9]+)'
-            pattern = re.compile(f'<p>{ base_placeholder }</p>|{ base_placeholder }')
+            pattern = re.compile(f'<p>{base_placeholder}</p>|{base_placeholder}')
             processed_text = pattern.sub(substitute_match, text)
         else:
             return text