diff --git a/C4/Search.pm b/C4/Search.pm
index 0ff4d2361e..75da21a4e6 100644
--- a/C4/Search.pm
+++ b/C4/Search.pm
@@ -390,6 +390,12 @@ sub getRecords {
             elsif ( $sort eq "title_za" || $sort eq "title_dsc" ) {
                 $sort_by .= "1=4 >i ";
             }
+            elsif ( $sort eq "biblionumber_az" || $sort eq "biblionumber_asc" ) {
+                $sort_by .= "1=12 <i ";
+            }
+            elsif ( $sort eq "biblionumber_za" || $sort eq "biblionumber_dsc" ) {
+                $sort_by .= "1=12 >i ";
+            }
             else {
                 warn "Ignoring unrecognized sort '$sort' requested" if $sort_by;
             }
diff --git a/etc/zebradb/marc_defs/marc21/biblios/biblio-koha-indexdefs.xml b/etc/zebradb/marc_defs/marc21/biblios/biblio-koha-indexdefs.xml
index c405228d45..7b1895968b 100644
--- a/etc/zebradb/marc_defs/marc21/biblios/biblio-koha-indexdefs.xml
+++ b/etc/zebradb/marc_defs/marc21/biblios/biblio-koha-indexdefs.xml
@@ -1196,6 +1196,8 @@
   <index_subfields tag="999" subfields="c">
     <target_index>Local-Number:n</target_index>
     <target_index>Local-Number:w</target_index>
+  </index_subfields>
+  <index_subfields tag="999" subfields="c" zeropad="1">
     <target_index>Local-Number:s</target_index>
   </index_subfields>
   <!--record.abs line 269: melm 999$d      biblioitemnumber:n,biblioitemnumber:w,biblioitemnumber:s-->
diff --git a/etc/zebradb/marc_defs/marc21/biblios/biblio-zebra-indexdefs.xsl b/etc/zebradb/marc_defs/marc21/biblios/biblio-zebra-indexdefs.xsl
index 626c44c5b3..b3222fadb5 100644
--- a/etc/zebradb/marc_defs/marc21/biblios/biblio-zebra-indexdefs.xsl
+++ b/etc/zebradb/marc_defs/marc21/biblios/biblio-zebra-indexdefs.xsl
@@ -1261,11 +1261,18 @@ definition file (probably something like {biblio,authority}-koha-indexdefs.xml)
   <xslo:template mode="index_subfields" match="marc:datafield[@tag='999']">
     <xslo:for-each select="marc:subfield">
       <xslo:if test="contains('c', @code)">
-        <z:index name="Local-Number:n Local-Number:w Local-Number:s">
+        <z:index name="Local-Number:n Local-Number:w">
           <xslo:value-of select="."/>
         </z:index>
       </xslo:if>
     </xslo:for-each>
+    <xslo:for-each select="marc:subfield">
+      <xslo:if test="contains('c', @code)">
+        <z:index name="Local-Number:s">
+          <xslo:value-of select="format-number(.,&quot;00000000000&quot;)"/>
+        </z:index>
+      </xslo:if>
+    </xslo:for-each>
     <xslo:for-each select="marc:subfield">
       <xslo:if test="contains('d', @code)">
         <z:index name="biblioitemnumber:n biblioitemnumber:w biblioitemnumber:s">
diff --git a/etc/zebradb/xsl/koha-indexdefs-to-zebra.xsl b/etc/zebradb/xsl/koha-indexdefs-to-zebra.xsl
index f20c48871f..2bdbbf0da6 100644
--- a/etc/zebradb/xsl/koha-indexdefs-to-zebra.xsl
+++ b/etc/zebradb/xsl/koha-indexdefs-to-zebra.xsl
@@ -279,6 +279,7 @@ definition file (probably something like {biblio,authority}-koha-indexdefs.xml)
     <xsl:template name="handle-one-index-subfields">
         <xsl:variable name="offset"><xsl:value-of select="@offset"/></xsl:variable>
         <xsl:variable name="length"><xsl:value-of select="@length"/></xsl:variable>
+        <xsl:variable name="zeropad"><xsl:value-of select="@zeropad"/></xsl:variable>
         <xsl:variable name="indexes">
             <xsl:call-template name="get-target-indexes"/>
         </xsl:variable>
@@ -302,6 +303,9 @@ definition file (probably something like {biblio,authority}-koha-indexdefs.xml)
                                     <xsl:value-of select="$length"/>
                                     <xsl:text>)</xsl:text>
                                 </xsl:when>
+                                <xsl:when test="@zeropad">
+                                    <xsl:text>format-number(.,"00000000000")</xsl:text>
+                                </xsl:when>
                                 <xsl:otherwise>
                                     <xsl:text>.</xsl:text>
                                 </xsl:otherwise>