EXHIBIT 10.13

EXECUTION COPY

PUT OPTION AGREEMENT

THIS PUT OPTION AGREEMENT (this “Agreement”), dated as of December 8, 2006, is
entered into by and among AutovaxID Investment LLC, a Missouri limited liability
company (“Fund”), U.S. Bancorp Community Investment Corporation, a Delaware
corporation (“USB CIC”), and Biolender II, LLC, a Delaware limited liability
company (“Purchaser”).

W I T N E S S E T H:

WHEREAS, USB CIC is the sole member of Fund, with USB CIC owning a 100% interest
in the capital, profits, losses, cashflow, deductions and credits of Fund (the
“Interest”); and

WHEREAS, Fund has invested in a “qualified equity investment” in St. Louis New
Markets Tax Credit Fund-II, LLC, a Missouri limited liability company, and
expects to be allocated New Markets Tax Credits pursuant to Section 45D of the
Internal Revenue Code of 1986, as amended (the “Code”) with respect to such
investment beginning on December 8, 2006;

WHEREAS, Purchaser desires to grant to USB CIC the right to sell the Interest on
the terms and subject to the conditions set forth herein; and

WHEREAS, Fund consents to Purchaser’s ability to purchase the Interest on the
terms and subject to the conditions set forth herein;

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the parties agree as follows:

1. Commencing on the date seven years and one (1) day after the Effective date
(as such term is defined in that certain QLICI Loan Agreement, dated as of the
date hereof, between AutovaxID, Inc., a Florida corporation, and St. Louis New
Markets Tax Credit Fund-II, LLC, a Missouri limited liability company), USB CIC
shall have the right to require Purchaser to purchase the Interest. Such right
shall continue for a period of three (3) months (the “Exercise Period”). This
option may be exercised by USB CIC by (i) giving written notice to Purchaser at
any time during the Exercise Period or not more than 30 days before the
beginning of such period, and (ii) agreeing that the closing of the purchase of
the Interest pursuant to this Agreement shall occur not more than 30 days after
the date on which USB CIC delivers said notice to Purchaser. In the event that
USB CIC exercises its right to put the Interest to Purchaser, Purchaser shall
pay USB CIC $120,000.

The entire sales price to be paid by Purchaser, if any, is to be paid at the
closing in cash or immediately available funds, unless otherwise mutually
agreed. If Purchaser has insufficient assets to pay such sales price, USB CIC
shall not have recourse against the Fund or its members. If Purchaser does not
pay the sales price to USB CIC on the date set for closing, USB CIC may either:
(i) retain the Interest, or (ii) execute and deliver an assignment of the
Interest to Purchaser, in which case USB CIC would have no further interest in
the Fund, but shall have a claim against the Purchaser for the sales price, and
the Purchaser shall be the owner of the transferred Interest. Should the
Interest be put to Purchaser, each party is responsible for any

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costs of its own attorneys’ fees or otherwise incurred in connection with the
closing. Upon the receipt of the required sales price to be paid in exchange for
its interest, USB CIC shall transfer the Interest, free and clear of any liens,
charges, encumbrances or interests of any third party, and shall execute or
cause to be executed any documents required to fully transfer the Interest. As
of the effective date of such closing, USB CIC shall have no further interest in
the Fund. If USB CIC fails to exercise its put option pursuant to this
Agreement, this Agreement shall terminate.

2. This Agreement shall be binding upon and inure to the benefit of the parties
hereto and their heirs, executors, personal representatives, successors and
assigns. No party to this Agreement may assign the rights under this Agreement
without the consent of each other party hereto. Any amendment(s) to this
Agreement shall be effective only if set forth in writing and signed by each
party hereto.

3. Each provision of this Agreement shall be considered severable, and if for
any reason any provision that is not essential to the effectuation of the basic
purposes of the Agreement is determined to be invalid and contrary to any
existing or future law, such invalidity shall not impair the operation of or
affect those provisions of this Agreement that are valid.

4. No party hereto shall be deemed to have waived any rights hereunder unless
such waiver shall be in writing and signed by such party. The waiver by any
party of any breach of this Agreement shall not operate or be construed to be a
waiver of any subsequent breach.

 

5. This Agreement shall be construed and enforced in accordance with the laws of
the State of Delaware.

6. The execution of this Agreement constitutes the consent required of USB CIC
under Section 9.01 of the Fund’s Operating Agreement in order to transfer the
Interest.

7. This Agreement and any amendments hereto may be executed in several
counterparts, each of which shall be deemed to be an original copy, and all of
which together shall constitute one agreement binding on all parties hereto,
notwithstanding that all the parties shall not have signed the same counterpart.
This Agreement may also be executed as facsimile originals and each copy of this
Agreement bearing the facsimile transmitted signature of any party’s authorized
representative shall be deemed to be an original.

[No further text on this page; signature page follows.]

 

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IN WITNESS WHEREOF, the parties have executed this Agreement as of the date and
year first written above.

 

AutovaxID Investment LLC,

a Missouri limited liability company

By:   St. Louis Development Corporation Its:   Manager   By:    

/s/ Rodney Crim

      Rodney Crim   Its:     Executive Director U.S. Bancorp Community
Investment Corporation, a Delaware corporation By:  

/s/ Matthew Philpott

  Matthew Philpott Its:   Business Development Associate

Biolender II, LLC,

a Delaware limited liability company

By:   Biovest International, Inc. Its:   Member   By:    

/s/ Steven Arikian

      Steven Arikian, M.D.   Its:     Chairman & CEO