EXHIBIT 3.6

                       LIMITED LIABILITY COMPANY AGREEMENT
                                       OF
                             VERASUN FORT DODGE, LLC

     1. GENERAL. The undersigned sole member of VeraSun Fort Dodge, LLC, a
Delaware limited liability company ("Company"), makes this Limited Liability
Company Agreement as of December 31, 2005 ("Agreement"). The undersigned member
agrees to conduct the Company's affairs in a manner consistent with the Delaware
Limited Liability Company Act, as amended ("Act"), the Company's Certificate of
Formation ("Certificate") and this Agreement. In the event of any conflict, this
Agreement shall control to the extent permitted by law. The provisions of this
Agreement are for the regulation of the member and the Company, are not intended
for the benefit of non-member creditors and do not grant any rights to
non-member creditors.

     2. DURATION OF COMPANY. The Company shall have perpetual existence unless
and until dissolved by action of the manager.

     3. PURPOSE. The purpose of the Company shall be to construct, own and
operate a fuel ethanol plant near Fort Dodge, Iowa and to engage in such other
activities as are permitted under the Act and are determined from time to time
by the manager.

     4. MEMBERSHIP INTERESTS. Membership interests in the Company shall be
expressed in percentages. VeraSun Energy Corporation (ID# DB050019), a South
Dakota corporation ("VEC"), holds a 100-percent membership interest in the
Company.

     5. MANAGEMENT BY MANAGER. The affairs of the Company shall be managed by a
manager. The manager shall have authority to make all decisions with respect to
the Company as provided in Section 7. The manager shall have authority to
execute documents on behalf of the Company, and the signature of the manager on
behalf of the Company shall be binding on the Company. The member in the
capacity of member shall not have authority to bind the Company.

     6. APPOINTMENT OF MANAGER. The member shall have authority to appoint and
remove the manager. VEC shall be the initial manager and shall serve in such
capacity until its resignation, removal, death or any incapacity rendering it
unable to function as manager. Any manager may resign by notice to the Company.

     7. APPROVAL OF MATTERS ON BEHALF OF THE COMPANY. Subject to any appointment
of the manager as may occur from time to time in accordance with Section 6, the
manager (and not the member) shall have sole and exclusive authority to take any
and all action required to be taken to authorize and approve any matter on
behalf of the Company, whether under the Act, this Agreement or otherwise,
including, without limitation, approval of a merger or consolidation of the
Company, a conversion of the Company, the incurrence of indebtedness by the
Company, the sale, lease, exchange, mortgage, pledge or other transfer of any or
all of the Company's property, the acquisition of property by the Company, any
change in the nature of the business of the Company, establishment of bank
accounts of the Company and all matters pertaining thereto, any tax or other
election by the Company or the dissolution of the Company.


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     8. LLC OFFICERS. in addition to the authority granted to the manager under
this Agreement, which shall not be reduced or otherwise affected by this
Section, the authority to manage and conduct the Company's day-to-day business
and affairs is hereby delegated to and shall be held by the officers of the
Company (each, an "LLC Officer") serving from time to time, each of whom shall
be an agent for the Company with the powers set forth herein or in any written
delegation of authority by the manager:

          (a) The LLC Officers appointed from time to time may include a Chief
Executive Officer, a President, one or more Vice Presidents, a Treasurer and a
Secretary. The Company may also have one or more Assistant Secretaries and
Assistant Treasurers. Each such LLC Officer shall have the duties and powers
provided for in this Section. The initial LLC Officers are named on EXHIBIT A to
this Agreement. The manager may from time to time also appoint such other LLC
Officers and agents, if any, having such duties and powers as the manager in its
discretion may deem necessary or appropriate.

          (b) Appointment of any LLC Officer, whether hereunder or by the
manager, shall not in and of itself create contract rights. An LLC Officer may
hold more than one office in the Company, including the offices of Chief
Executive Officer, President and Secretary. Each LLC Officer shall hold office
at the pleasure of the manager or until the LLC Officer's death, resignation or
removal, with or without cause and without any need for explanation, by action
by the manager. Any LLC Officer may resign at any time upon written notice to
the Company.

          (c) In addition to such authority as any LLC Officer may have under
this Agreement or as may from time to time be expressly delegated to any LLC
Officer by the manager, each LLC Officer shall have authority to execute such
contracts, certificates, documents and instruments on behalf of the Company as
are within the scope of the LLC Officer's level of responsibility and authority
within the Company and are entered into in the ordinary course of business in
respect of the LLC Officer executing the same or within the established practice
of the Company with respect to the delegation of authority to such LLC Officer.

          (d) The duties and powers of each of the following LLC Officers, if
appointed, shall be as follows:

               (i) CHIEF EXECUTIVE OFFICER. The Chief Executive Officer shall
     have overall responsibility for the management of the business of the
     Company and for the operations and functioning of the Company, subject to
     the oversight and control of the manager.

               (ii) PRESIDENT. The President shall have and exercise such powers
     and duties as may be delegated to or vested in such LLC Officer from time
     to time by the manager.

               (iii) VICE PRESIDENTS. The Vice President or Vice Presidents, if
     any, shall have such powers and perform such duties and responsibilities as
     may be prescribed from time to time by the manager. The manager may assign
     a description designation in the title of any Vice President and, if there
     is more than one Vice President, may


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     designate which Vice President shall perform any of the duties or exercise
     any of the powers of the Vice Presidents.

               (iv) TREASURER. The Treasurer have the custody of the Company
     funds and securities and shall keep complete and accurate accounts of all
     receipts and disbursements of the Company and shall deposit all monies and
     other valuable effects of the Company in the Company's name and to its
     credit in such banks and other depositories as may be approved from time to
     time by the manager. The Treasurer shall disburse the funds of the Company,
     taking proper vouchers and receipts for such disbursements. The Treasurer
     shall have such other powers and perform such other duties as the manager
     shall from time to time prescribe. The Company may also have one or more
     Assistant Treasurers having duties and authority with respect to the
     matters within the authority of the Treasurer as the manager may from time
     to time prescribe.

               (v) SECRETARY. The Secretary shall keep a record of all member
     meetings and any action of the member in a book or books to be kept for
     that purpose. The Secretary shall give, or cause to be given, notice of all
     member meetings and shall perform such other duties as may be prescribed by
     the manager, under whose supervision the Secretary shall be. The Secretary
     shall see that all books, reports, statements, certificates and other
     documents and records required by law to be kept or filed are properly kept
     or filed, as the case may be. The Company may also have one or more
     Assistant Secretaries having duties and authority with respect to the
     matters within the authority of the Secretary as the manager may from time
     to time prescribe.

     9. LIMITED LIABILITY; INDEMNIFICATION. The liability of the member and the
manager shall be limited to the fullest extent permitted by law. The Company
shall indemnify the manager against any loss, cost and expense the manager may
incur by reason of acting as manager and shall defend the manager against any
claims made against the manager by reason of serving in such capacity.

     10. CAPITAL CONTRIBUTIONS. With the agreement of the manager, the member
may make capital contributions to the Company. The member shall not be obligated
to make any capital contribution to the Company.

     11. PROFITS AND LOSSES. The profits and losses of the Company shall pass
through to the member and be reported by the member for tax purposes.

     12. DISTRIBUTIONS OF CASH OR OTHER PROPERTY. The Company will from time to
time make distributions of cash or property to the member, at such times and in
such amounts as are determined by the manager.

     13. TRANSFERS OF INTERESTS. Upon any transfer of an interest in the
Company, the transferee shall be an assignee only unless admitted as a member in
a writing executed by the manager and the transferee that binds the transferee
to all provisions of this Agreement and contains the consent of the manager to
admission of the transferee as a member.

     14. WITHDRAWAL; DISSOLUTION. The member does not have the right or power to
withdraw voluntarily from the Company. Any purported withdrawal shall be
ineffective, shall


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be a breach of this Agreement and shall not entitle the member to any
distribution from the Company. Notwithstanding the foregoing, the Company may be
dissolved at any time with the approval of the manager.

     15. AMENDMENTS. This Agreement may be amended only by a writing signed by
the member and the manager.

     IN WITNESS WHEREOF, THE MEMBER HAS EXECUTED THIS LIMITED LIABILITY COMPANY
AGREEMENT OF VERASUN FORT DODGE, LLC AS OF THE DATE FIRST SET FORTH ABOVE.

                                        VERASUN ENERGY CORPORATION


                                        BY: /S/ DONALD L. ENDRES
                                            ------------------------------------
                                        NAME: DONALD L. ENDRES
                                        TITLE: CHIEF EXECUTIVE OFFICER


ACKNOWLEDGMENT AND AGREEMENT BY MANAGER:

VERASUN ENERGY CORPORATION, MANAGER


BY: /S/ BRUCE A. JAMERSON
    ---------------------------------
NAME: BRUCE A. JAMERSON
TITLE: PRESIDENT


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                                                                       EXHIBIT A

                                  LLC OFFICERS


                                     
Chief Executive Officer                 Donald L. Endres
President and Chief Financial Officer   Bruce A. Jamerson
Vice President, Sales and Marketing     William L. Honnef
Vice President, Technology              Matthew K.R. Janes
Vice President, Corporate Development   Paul A. Schock
Vice President and General Counsel      John M. Schweitzer
Secretary and Treasurer                 Ginja R. Collins



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                             APPOINTMENT OF OFFICERS

     The undersigned sole manager and sole member of VeraSun Biodiesel, LLC,
VeraSun Charles City, LLC, VeraSun Fort Dodge, LLC, VeraSun Marketing, LLC and
VeraSun Welcome, LLC hereby appoints the officers listed on EXHIBIT A to the
respective offices set forth opposite their names effective as of May 1, 2006.

                                        VERASUN ENERGY CORPORATION


                                        By: /s/ Donald L. Endres
                                            ------------------------------------
                                        Name: Donald L. Endres
                                        Title: Chief Executive Officer


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                                                                       EXHIBIT A

                                  LLC OFFICERS


                                                 
Chief Executive Officer                             Donald L. Endres
President                                           Bruce A. Jamerson
Senior Vice President, Chief Financial Officer      Danny C. Herron
Senior Vice President, Sales and Marketing          William L. Honnef
Senior Vice President, Corporate Development        Paul A. Schock
Senior Vice President and General Counsel           John M. Schweitzer
Senior Vice President, Operations                   Paul J. Caudill
Vice President, Technology                          Matthew K.R. Janes
Vice President, Plant Operations                    Kevin T. Biehle
Vice President of Finance Secretary and Treasurer   Ginja R. Collins



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