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  <TITLE>S-8</TITLE>
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   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>As filed with the Securities and Exchange Commission on November&nbsp;12, 2024 </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="right"><B>Registration <FONT STYLE="white-space:nowrap">No.&nbsp;333-</FONT> </B></P>
  <P STYLE="font-size:4pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P> <P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P>
  <P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="margin-top:4pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>UNITED STATES </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>SECURITIES AND EXCHANGE COMMISSION </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B>Washington, D.C. 20549 </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
  <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>FORM <FONT
  STYLE="white-space:nowrap">S-8</FONT> </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>REGISTRATION STATEMENT </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B><I>UNDER </I></B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman" ALIGN="center"><B><I>THE
  SECURITIES ACT OF 1933 </I></B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:24pt; font-family:Times New Roman" ALIGN="center"><B>Synlogic, Inc. </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(Exact
  name of registrant as specified in its charter) </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center>
  <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
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  <TD VALIGN="top" ALIGN="center"><B>Delaware</B></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" ALIGN="center"><B><FONT STYLE="white-space:nowrap">26-1824804</FONT></B></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
  <TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(State or other jurisdiction of</B></P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>incorporation or organization)</B></P></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(I.R.S. Employer</B></P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Identification Number)</B></P></TD></TR>
  </TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>PO Box 30 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Winchester, MA 01890 </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(617) <FONT STYLE="white-space:nowrap">659-2802</FONT> </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Address, including zip code, and telephone number, including area code, of registrant&#146;s principal executive offices) </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>2015 Employee Stock Purchase Plan </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Full Title of the Plan) </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Antoine Awad </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Principal
  Executive Officer </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Synlogic, Inc. </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>PO Box 30 </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Winchester,
  MA 01890 </B></P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>(617) <FONT STYLE="white-space:nowrap">659-2802</FONT> </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Name, address, including zip code, and telephone number, including area code, of agent for service) </B></P>
  <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P><center> <P STYLE="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%">&nbsp;</P></center>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a <FONT STYLE="white-space:nowrap">non-accelerated</FONT>
  filer, a smaller reporting company or an emerging growth company. See the definitions of &#147;large accelerated filer,&#148; &#147;accelerated filer,&#148; &#147;smaller reporting company,&#148; and &#147;emerging growth company&#148; in Rule <FONT
  STYLE="white-space:nowrap">12b-2</FONT> of the Exchange Act. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">
  
  
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  <TD VALIGN="bottom">Large&nbsp;accelerated&nbsp;filer</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9744;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">Accelerated filer</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9744;</TD></TR>
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  <TD VALIGN="bottom"><FONT STYLE="white-space:nowrap">Non-accelerated&nbsp;filer</FONT></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9746;</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">Smaller&nbsp;reporting&nbsp;company</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9746;</TD></TR>
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  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
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  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom">Emerging growth company</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="bottom">&#9744;</TD></TR>
  </TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period
  for complying with any new or revised financial accounting standards provided pursuant to Section&nbsp;7(a)(2)(B) of the Securities Act.&#8194;&#9744; </P> <P STYLE="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&nbsp;</P> <P STYLE="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&nbsp;</P>
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   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>EXPLANATORY NOTE </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">On November&nbsp;23, 2016, the Board of Directors of the Registrant suspended the Registrant&#146;s 2015 Employee Stock Purchase Plan (the &#147;ESPP&#148;)
  pursuant to the terms of the ESPP. On December&nbsp;
  19, 2019, the Board of Directors of the Registrant reactivated the ESPP, for which a Registration Statement of the Registrant on Form <FONT STYLE="white-space:nowrap">S-8</FONT> (File No.<A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000110465915069371/a15-14644_9s8.htm">
  <U><FONT STYLE="white-space:nowrap">&nbsp;333-207299</FONT></U></A>) is effective. This Registration Statement on Form <FONT STYLE="white-space:nowrap">S-8</FONT> is being filed for the purpose of registering an additional 91,861 shares of the
  Registrant&#146;s Common Stock issuable under the ESPP, as a result of the operation of an automatic annual increase provision therein, which added 91,861 shares of Common Stock. This Registration Statement registers additional securities of the
  same class as other securities for which registration statements filed on Form <FONT STYLE="white-space:nowrap">S-8</FONT> of the Registrant relating to one or more employee benefit plans is effective (File Nos. <A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000110465915069371/a15-14644_9s8.htm">
  <U><FONT STYLE="white-space:nowrap">333-207299</FONT></U></A>, <A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000110465916108376/a16-7287_1s8.htm"><U><FONT STYLE="white-space:nowrap">333-210466</FONT></U></A>, <A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000119312520071060/d824553ds8.htm">
  <U><FONT STYLE="white-space:nowrap">333-237105</FONT></U></A>, <A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000119312521093473/d115297ds8.htm"><U><FONT STYLE="white-space:nowrap">333-254689</FONT></U></A>, <A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000119312522077896/d339035ds8.htm">
  <U><FONT STYLE="white-space:nowrap">333-263629</FONT></U></A> and <A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000119312523083004/d489396ds8.htm">333-270926</A>). </P>
  <P STYLE="margin-top:24pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>INCORPORATION BY REFERENCE OF CONTENTS OF </B></P>
  <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>REGISTRATION STATEMENT ON FORM <FONT STYLE="white-space:nowrap">S-8</FONT> </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Pursuant to Instruction E of Form <FONT STYLE="white-space:nowrap">S-8,</FONT> the contents of the Registration Statement on Form <FONT
  STYLE="white-space:nowrap">S-8</FONT> filed with the Securities and Exchange Commission on October&nbsp;
  6, 2015 (File No.<A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000119312517304682/d471033ds8.htm"><U><FONT STYLE="white-space:nowrap">333-207299</FONT></U></A>) are incorporated by reference herein. </P>
  </DIV></Center>
  
  
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   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><B>Exhibit Index </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">
  
  
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  <TD VALIGN="bottom" ROWSPAN="2" ALIGN="center"><B>Exhibit<BR>Number</B></TD>
  <TD VALIGN="bottom" ROWSPAN="2">&nbsp;</TD>
  <TD VALIGN="bottom" ROWSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Exhibit Description</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" COLSPAN="5" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><B>Incorporated by</B><br><B>Reference</B></TD>
  <TD VALIGN="bottom" ROWSPAN="2">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ROWSPAN="2" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><B>Filed<BR>Herewith</B></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><B>Form</B></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><B>Date</B></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center" STYLE="border-bottom:1.00pt solid #000000"><B>Number</B></TD></TR>
  
  
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  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>4.1</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000110465915069368/a15-14644_8ex3d1.htm">Amended and Restated Certificate of Incorporation. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center"><FONT STYLE="white-space:nowrap">8-K</FONT></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">10/6/2015</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">3.1</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD></TR>
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  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>4.2</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000119312517270395/d431294dex31.htm">Certificate of Amendment to Amended and Restated Certificate of Incorporation. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center"><FONT STYLE="white-space:nowrap">8-K</FONT></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">8/28/2017</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">3.1</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
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  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>4.3</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000119312517270395/d431294dex32.htm">Certificate of Amendment to Amended and Restated Certificate of Incorporation. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center"><FONT STYLE="white-space:nowrap">8-K</FONT></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">8/28/2017</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">3.2</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD></TR>
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  <TD HEIGHT="8"></TD>
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  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>4.4</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000110465915069368/a15-14644_8ex3d2.htm">Amended and Restated Bylaws. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center"><FONT STYLE="white-space:nowrap">8-K</FONT></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">10/6/2015</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">3.2</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>4.5</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000119312517309912/d471035dex45.htm">Form of Common Stock Certificate. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center"><FONT STYLE="white-space:nowrap">S-3</FONT></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">10/13/2017</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">4.5</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
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  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>5.1</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d883707dex51.htm">Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">X</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>23.1</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d883707dex231.htm">Consent of KPMG LLP, independent registered public accounting firm. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">X</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>23.2</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d883707dex51.htm">Consent of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. (included in Exhibit 5.1). </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">X</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>24.1</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="#sig">Power of Attorney. Reference is made to the signature page to the Registration Statement. </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">X</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>99.1#</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="http://www.sec.gov/Archives/edgar/data/1527599/000119312519321039/d853861dex101.htm">Synlogic, Inc. 2015 Employee Stock Purchase Plan, as amended.</A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center"><FONT STYLE="white-space:nowrap">8-K</FONT></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">12/20/2019</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">10.1</TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="8"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD>
  <TD HEIGHT="8" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" NOWRAP>107</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><A HREF="d883707dexfilingfees.htm">Calculation of Filing Fee Table </A></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">X</TD></TR>
  </TABLE> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
  <TR style = "page-break-inside:avoid">
  <TD WIDTH="2%" VALIGN="top" ALIGN="left">#</TD>
  <TD ALIGN="left" VALIGN="top"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman; " ALIGN="left">Indicates management contract or compensatory plan. </P></TD></TR></TABLE>
  </DIV></Center>
  
  
  <p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
  <HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Signatures </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant has duly caused this Registration Statement on Form <FONT
  STYLE="white-space:nowrap">S-8</FONT> to be signed on its behalf by the undersigned, thereunto duly authorized, in Winchester, Massachusetts on November&nbsp;12, 2024. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="40%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt">
  
  
  <TR>
  
  <TD WIDTH="7%"></TD>
  
  <TD VALIGN="bottom" WIDTH="1%"></TD>
  <TD WIDTH="92%"></TD></TR>
  
  
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top" COLSPAN="3"><B>SYNLOGIC, INC.</B></TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top">By:</TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:1pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Antoine Awad</P></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top">Antoine Awad</TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="top"></TD>
  <TD VALIGN="bottom">&nbsp;</TD>
  <TD VALIGN="top"><I>Principal Executive Officer</I></TD></TR>
  </TABLE>
  </DIV></Center>
  
  
  <p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
  <HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
  
  
  <Center><DIV STYLE="width:8.5in" align="left">
   <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B><A NAME="sig"></A>Power of Attorney </B></P>
  <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Antoine Awad and Mary Beth Dooley, and each
  of them acting individually, as his or her true and lawful <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorneys-in-fact</FONT></FONT> and agents, each with full power of substitution, for him or her in any and all capacities,
  to sign any and all amendments to this Registration Statement, including post-effective amendments or any abbreviated registration statement and any amendments thereto filed pursuant to Rule 462(b) increasing the number of securities for which
  registration is sought, and to file the same, with all exhibits thereto and other documents in connection therewith, with the SEC, granting unto said <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorneys-in-fact</FONT></FONT>
  and agents, with full power of each to act alone, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully for all intents and purposes as he or she might or could
  do in person, hereby ratifying and confirming all that said <FONT STYLE="white-space:nowrap"><FONT STYLE="white-space:nowrap">attorneys-in-fact</FONT></FONT> and agents, or his, her or their substitute or substitutes, may lawfully do or cause to be
  done by virtue hereof. </P> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the
  capacities and on the dates indicated. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
  <TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt" ALIGN="center">
  
  
  <TR>
  
  <TD WIDTH="28%"></TD>
  
  <TD VALIGN="bottom" WIDTH="1%"></TD>
  <TD WIDTH="50%"></TD>
  
  <TD VALIGN="bottom" WIDTH="1%"></TD>
  <TD WIDTH="20%"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
  <TD VALIGN="bottom" ALIGN="center"><B>Name</B></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center"><B>Title</B></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center"><B>Date</B></TD></TR>
  
  
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Antoine Awad</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Antoine Awad</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Principal Executive Officer</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"><I>(Principal Executive Officer)</I></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">November&nbsp;12, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Mary Beth Dooley</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Mary Beth Dooley</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Head of Finance</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman"><I>(Principal Financial Officer and Principal Accounting Officer)</I></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">November&nbsp;12, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Peter Barrett</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Peter Barrett</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Chairman of the Board</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">November&nbsp;12, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ James Flynn</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>James Flynn</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">November&nbsp;12, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Michael Heffernan</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Michael Heffernan</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">November&nbsp;12, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Nick Leschly</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Nick Leschly</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">November&nbsp;12, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Edward Mathers</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Edward Mathers</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">November&nbsp;12, 2024</TD></TR>
  <TR STYLE="font-size:1pt">
  <TD HEIGHT="16"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD>
  <TD HEIGHT="16" COLSPAN="2"></TD></TR>
  <TR STYLE="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
  <TD VALIGN="bottom"> <P STYLE="margin-top:0pt; margin-bottom:0pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman" ALIGN="center">/s/ Richard P. Shea</P>
  <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Richard P. Shea</B></P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom"> <P STYLE=" margin-top:0pt ; margin-bottom:0pt; margin-left:1.00em; text-indent:-1.00em; font-size:10pt; font-family:Times New Roman">Director</P></TD>
  <TD VALIGN="bottom">&nbsp;&nbsp;</TD>
  <TD VALIGN="bottom" ALIGN="center">November&nbsp;12, 2024</TD></TR>
  </TABLE>
  </DIV></Center>
  
  </BODY></HTML>
metadata_documents: [{"type": "S-8", "sequence": "1", "filename": "d883707ds8.htm", "description": "S-8", "secsgml_size_bytes": 36611}]
metadata_filer: {"company-data": {"conformed-name": "SYNLOGIC, INC.", "cik": "0001527599", "assigned-sic": "2834", "organization-name": "03 Life Sciences", "irs-number": "261824804", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-283164", "film-number": "241449316"}, "business-address": {"street1": "PO BOX 30", "city": "WINCHESTER", "state": "MA", "zip": "01890", "phone": "617-659-2802"}, "mail-address": {"street1": "PO BOX 30", "city": "WINCHESTER", "state": "MA", "zip": "01890"}, "former-company": {"former-conformed-name": "Mirna Therapeutics, Inc.", "date-changed": "20110809"}}
text: S-8
  As filed with the Securities and Exchange Commission on November 12, 2024
  Registration
  No. 333-
  UNITED STATES
  SECURITIES AND EXCHANGE COMMISSION
  Washington, D.C. 20549
  FORM
  S-8
  REGISTRATION STATEMENT
  UNDER
  THE
  SECURITIES ACT OF 1933
  Synlogic, Inc.
  (Exact
  name of registrant as specified in its charter)
  Delaware
  26-1824804
  (State or other jurisdiction of
  incorporation or organization)
  (I.R.S. Employer
  Identification Number)
  PO Box 30
  Winchester, MA 01890
  (617)
  659-2802
  (Address, including zip code, and telephone number, including area code, of registrant's principal executive offices)
  2015 Employee Stock Purchase Plan
  (Full Title of the Plan)
  Antoine Awad
  Principal
  Executive Officer
  Synlogic, Inc.
  PO Box 30
  Winchester,
  MA 01890
  (617)
  659-2802
  (Name, address, including zip code, and telephone number, including area code, of agent for service)
  Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a
  non-accelerated
  filer, a smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule
  12b-2
  of the Exchange Act.
  Large accelerated filer
  ☐
  Accelerated filer
  ☐
  Non-accelerated filer
  ☒
  Smaller reporting company
  ☒
  Emerging growth company
  ☐
  If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period
  for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐
  EXPLANATORY NOTE
  On November 23, 2016, the Board of Directors of the Registrant suspended the Registrant's 2015 Employee Stock Purchase Plan (the "ESPP")
  pursuant to the terms of the ESPP. On December 
  19, 2019, the Board of Directors of the Registrant reactivated the ESPP, for which a Registration Statement of the Registrant on Form
  S-8
  (File No.
  333-207299
  ) is effective. This Registration Statement on Form
  S-8
  is being filed for the purpose of registering an additional 91,861 shares of the
  Registrant's Common Stock issuable under the ESPP, as a result of the operation of an automatic annual increase provision therein, which added 91,861 shares of Common Stock. This Registration Statement registers additional securities of the
  same class as other securities for which registration statements filed on Form
  S-8
  of the Registrant relating to one or more employee benefit plans is effective (File Nos.
  333-207299
  ,
  333-210466
  ,
  333-237105
  ,
  333-254689
  ,
  333-263629
  and
  333-270926
  ).
  INCORPORATION BY REFERENCE OF CONTENTS OF
  REGISTRATION STATEMENT ON FORM
  S-8
  Pursuant to Instruction E of Form
  S-8,
  the contents of the Registration Statement on Form
  S-8
  filed with the Securities and Exchange Commission on October 
  6, 2015 (File No.
  333-207299
  ) are incorporated by reference herein.
  Exhibit Index
  Exhibit
  Number
  Exhibit Description
  Incorporated by
  Reference
  Filed
  Herewith
  Form
  Date
  Number
  4.1
  Amended and Restated Certificate of Incorporation.
  8-K
  10/6/2015
  3.1
  4.2
  Certificate of Amendment to Amended and Restated Certificate of Incorporation.
  8-K
  8/28/2017
  3.1
  4.3
  Certificate of Amendment to Amended and Restated Certificate of Incorporation.
  8-K
  8/28/2017
  3.2
  4.4
  Amended and Restated Bylaws.
  8-K
  10/6/2015
  3.2
  4.5
  Form of Common Stock Certificate.
  S-3
  10/13/2017
  4.5
  5.1
  Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
  X
  23.1
  Consent of KPMG LLP, independent registered public accounting firm.
  X
  23.2
  Consent of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. (included in Exhibit 5.1).
  X
  24.1
  Power of Attorney. Reference is made to the signature page to the Registration Statement.
  X
  99.1#
  Synlogic, Inc. 2015 Employee Stock Purchase Plan, as amended.
  8-K
  12/20/2019
  10.1
  107
  Calculation of Filing Fee Table
  X
  #
  Indicates management contract or compensatory plan.
  Signatures
  Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant has duly caused this Registration Statement on Form
  S-8
  to be signed on its behalf by the undersigned, thereunto duly authorized, in Winchester, Massachusetts on November 12, 2024.
  SYNLOGIC, INC.
  By:
  /s/ Antoine Awad
  Antoine Awad
  Principal Executive Officer
  Power of Attorney
  KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Antoine Awad and Mary Beth Dooley, and each
  of them acting individually, as his or her true and lawful
  attorneys-in-fact
  and agents, each with full power of substitution, for him or her in any and all capacities,
  to sign any and all amendments to this Registration Statement, including post-effective amendments or any abbreviated registration statement and any amendments thereto filed pursuant to Rule 462(b) increasing the number of securities for which
  registration is sought, and to file the same, with all exhibits thereto and other documents in connection therewith, with the SEC, granting unto said
  attorneys-in-fact
  and agents, with full power of each to act alone, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully for all intents and purposes as he or she might or could
  do in person, hereby ratifying and confirming all that said
  attorneys-in-fact
  and agents, or his, her or their substitute or substitutes, may lawfully do or cause to be
  done by virtue hereof.
  Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the
  capacities and on the dates indicated.
  Name
  Title
  Date
  /s/ Antoine Awad
  Antoine Awad
  Principal Executive Officer
  (Principal Executive Officer)
  November 12, 2024
  /s/ Mary Beth Dooley
  Mary Beth Dooley
  Head of Finance
  (Principal Financial Officer and Principal Accounting Officer)
  November 12, 2024
  /s/ Peter Barrett
  Peter Barrett
  Chairman of the Board
  November 12, 2024
  /s/ James Flynn
  James Flynn
  Director
  November 12, 2024
  /s/ Michael Heffernan
  Michael Heffernan
  Director
  November 12, 2024
  /s/ Nick Leschly
  Nick Leschly
  Director
  November 12, 2024
  /s/ Edward Mathers
  Edward Mathers
  Director
  November 12, 2024
  /s/ Richard P. Shea
  Richard P. Shea
  Director
  November 12, 2024