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Exhibit 10.18
 AMENDMENT NO. 2 TO
MASTER LOAN AGREEMENT
 Amendment US BIO WOODBURY, LLC, Borrower AGSTAR FINANCIAL SERVICES, PCA Lender
 RECITALS
 MLA First Supplement Second Supplement Third
Supplement Fourth Supplement Loan Agreement
   AGREEMENT
  Amendments to MLA
 Section 1.01:




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Accounts
 Affiliate
 Affiliated Borrower
 Borrowing Base
 Borrowing Base Certificate
 Capital Expenditures
 Compliance Certificate




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Default
 EBITDA
 Eligible Accounts Receivable
 (a)
    
    that portion of Accounts unpaid forty-five (45) days or more after the invoice
date;(b)
    
    that portion of Accounts that is disputed or subject to a claim of offset or a
contra account;(c)
    
    that portion of Accounts for which goods giving rise to such Account have not yet
been shipped or for which rendition of services have not yet been performed, as applicable,
by the Borrower to the customer;(d)
    
    Accounts owed by any unit of government, whether foreign or domestic (except
Incentive Payments) unless, with respect to Accounts owed by the government of the United
States, the Federal Assignment of Claims Act of 1940, as amended (31 U.S.C. § 3727 et seq.
and 41 U.S.C. § 15 et seq.), has been complied with to the Lenders reasonable
satisfaction;(e)
    
    Accounts owed by an account debtor located outside the United States unless such
Account is backed by a letter of credit or foreign credit insurance reasonably acceptable
to the Lender which is in the possession of or has been assigned to the Lender;(f)
    
    Accounts owed by an account debtor that is insolvent, the subject of bankruptcy
proceedings or has gone out of business;(g)
    
    Accounts owed by a member, Guarantor, Affiliate, director,
officer or employee of the Borrower, other than accounts owed by Provista
Renewable Fuels Marketing, LLC, United Bio Energy Ingredients, LLC, or any
Affiliated Borrower;(h)
    
    Accounts not subject to a duly perfected Lien in favor of the
Lender or which are subject to any Lien in favor of any Person other than the




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Lender, other than Permitted Liens pursuant to Section 5.02(a)(iv)
including any payment or performance bond;(i)
    
    that portion of Accounts that has been restructured, extended,
or reduced other than in the ordinary course of business;(j)
    
    that portion of Accounts that constitutes advertising, finance
charges, service charges or sales or excise taxes; and(k)
    
    Accounts, or portions thereof, otherwise deemed ineligible by
the Lender, in its good faith discretion, exercised in its reasonable business
judgment with respect to which the Lender has provided at least two (2)
Business Days prior written notice to the Borrower.
  Eligible Inventory
 (a)
    
    covered by documents of title, instruments, or chattel paper
when these documents, instruments and paper are not owned and held by the
Borrower or are subject to competing Liens;(b)
    
    intended to be sold outside of the ordinary course of business;(c)
    
    consigned, sold or leased to others or held on consignment or lease from others or
subject to a bailment;(d)
    
    subject to a competing Lien, other than a Permitted Lien;(e)
    
    paid for in advance with progress payments or any other sums to the Borrower in
anticipation of the sale and delivery of Inventory;(f)
    
    that is obsolete or not salable in the ordinary course of business; and(g)
    
    that the Lender, in its good faith discretion, disqualifies as
Eligible Inventory, exercised in its reasonable business judgment with respect
to which the Lender has provided at least two (2) Business Days prior written
notice to the Borrower.




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Environment
 Environmental Laws
 Excess Cash Flow Payment
 Financial Statements
 Fixed Charge Coverage Ratio
 Governmental Authority
 Guarantor
 Hazardous Material




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Incentive Payments
 Income Taxes
 Lien
 Long Term Marketing Agreement
 Material Adverse Effect
 Maximum Excess Cash Flow Payment 
 Net Income
 Net Worth
 Owners Equity
 Permitted Liens
 Reinvestment Distributions




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Release
 Senior Officer
 Subsidiary
 Section 2.04(b)
 Excess Cash Flow . Excess Cash Flow Payment Maximum Excess Cash Flow
Payment




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Sections 2.05 and 5.01(f)
 Section 5.01(c)
 Reporting Requirements
 Financial Statements




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Section 5.01(e):
 Section 5.02(b)
 Distributions, etc




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Tax Distributions Allowed Distributions Reinvestment Distributions Excess Distributions
 Section 5.02(c)
 Capital Expenditures
 Conditions to Effectiveness of this Amendment .
 Representations and Warranties .




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Miscellaneous .
 Effect; Ratification
 Loan Documents
 Counterparts
 Severability
 GOVERNING LAW
 WAIVER OF JURY TRIAL




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AMENDMENT NO. 2 TO
MASTER LOAN AGREEMENT
 
   BORROWER:US BIO WOODBURY, LLC,
a Michigan limited liability companyBy:
    
    /s/ Kelly S. Langley

      Kelly S. LangleyIts: TreasurerLENDER:AGSTAR FINANCIAL SERVICES, PCA,
a United States corporationBy:
    
    /s/ Mark Schmidt

      Mark Schmidt
      Its: Vice President




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EXHIBIT A
 CONSENT AND REAFFIRMATION OF GUARANTY
    US BIOENERGY CORPORATIONBy:
    /s/ Kelly S. LangleyName:    
    Kelly S. LangleyIts:  Treasurer