<DOCUMENT>
<TYPE>EX-5.1
<SEQUENCE>2
<FILENAME>v011698_ex5-1.txt
<TEXT>

                               Jenkens & Gilchrist
                           A PROFESSIONAL CORPORATION
                                                             AUSTIN, TEXAS
                                1445 ROSS AVENUE             (512) 499-3800
                                   SUITE 3200               CHICAGO, ILLINOIS
                               DALLAS, TEXAS 75202           (312) 425-3900
                                                             HOUSTON, TEXAS
                                 (214) 855-4500              (713) 951-3300
                            FACSIMILE (214) 855-4300     LOS ANGELES, CALIFORNIA
                                                             (310) 820-8800
                                 www.jenkens.com           NEW YORK, NEW YORK
                                                             (212) 704-6000
                                                           SAN ANTONIO, TEXAS
                                                             (210) 246-5000
                                                            WASHINGTON, D.C.
                                                             (202) 326-1500

                                January 27, 2005

Dyadic International, Inc.
140 Intracoastal Pointe Drive, Suite 404
Jupiter, Florida  33477

      Re: Dyadic International, Inc. - Registration Statement on Form S-8

Ladies and Gentlemen:

      We are counsel to Dyadic International, Inc., a Delaware corporation (the
"Company"), and have acted as such in connection with the preparation of the
Registration Statement on Form S-8 (the "Registration Statement") to be filed
with the Securities and Exchange Commission on or about January 27, 2005, under
the Securities Act of 1933, as amended (the "Securities Act"), relating to
5,133,823 shares (the "Shares") of the $0.001 par value common stock (the
"Common Stock") of the Company that have been or may be issued by the Company
pursuant to the Dyadic International, Inc. 2001 Equity Compensation Plan (the
"Plan"), including up to 821,000 Shares that may be issued upon the exercise of
outstanding options previously granted under the Plan (the "Options") and up to
4,312,823 Shares that may be issued in the future as restricted stock awards
under the Plan ("Future Awards") or upon the exercise of Options that may be
granted in the future under the Plan ("Future Options"). The Plan was originally
adopted by Dyadic International (USA), Inc., a Florida corporation
("Dyadic-Florida"), which was acquired by the Company on October 29, 2004
through a merger with the Company's wholly-owned subsidiary (the "Merger"),
whereupon the Company assumed Dyadic-Florida's obligations under the Plan in
connection with the Merger.

      You have requested an opinion with respect to certain legal aspects of the
proposed offering. In connection therewith, we have examined and relied upon the
original, or copies identified to our satisfaction, of (1) the Restated
Certificate of Incorporation of the Company and the Amended and Restated Bylaws
of the Company, (2) minutes and records of the corporate proceedings of the
Company with respect to the Merger, the assumption of the Plan and the Options,
the reservation of 5,133,823 Shares to be issued pursuant to the Plan and to
which the Registration Statement relates, the issuance of the shares of Common
Stock pursuant to the Plan and related matters; (3) the Registration Statement
and exhibits thereto, including the Plan; and (4) such other documents and
instruments as we have deemed necessary for the expression of opinions herein
contained. In making the foregoing examinations, we have assumed the genuineness
of all signatures and the authenticity of all documents submitted to us as
originals, and the conformity to original documents of all documents submitted
to us as certified or photostatic copies. As to various questions of fact
material to this opinion, and as to the content and form of the Restated
Certificate of Incorporation, Amended and Restated Bylaws, minutes, records,
resolutions and other documents or writings of the Company, we have relied, to
the extent deemed reasonably appropriate, upon representations or certificates
of officers or directors of the Company and upon documents, records and
instruments furnished to us by the Company, without independent check or
verification of their accuracy.
<PAGE>

                               Jenkens & Gilchrist
                           A PROFESSIONAL CORPORATION

Dyadic International, Inc.
January 27, 2005
Page 2


Based upon our examination, consideration of, and reliance on the documents and
other matters described above, this firm is of the opinion that:

      (1)   All corporate actions necessary to authorize the issuance by the
            Company of the Shares upon the exercise of the Options have been
            duly and validly taken;

      (2)   Assuming (i) that all relevant corporate actions heretofore taken by
            the Company remain in full force and effect and (ii) that the Shares
            that may be purchased under the Options are issued, sold and
            delivered as contemplated by the Registration Statement and in
            accordance with the terms and conditions of the corporate
            authorizations and the Options and the Plan, such Shares will be
            duly authorized, validly issued, fully paid and nonassessable shares
            of Common Stock of the Company; and

      (3)   Assuming (i) any Future Awards and Future Options are properly
            authorized by all necessary corporate action by the Company in
            accordance with the Plan and (ii) that the Shares that may be
            purchased under the Future Options or that may be issued under the
            Future Awards are issued, sold and delivered as contemplated by the
            Registration Statement and in accordance with the terms and
            conditions of such corporate authorizations, the Plan and the Future
            Options or Future Awards, such Shares will be duly authorized,
            validly issued, fully paid and nonassessable shares of Common Stock
            of the Company.

      The opinions expressed in this letter assume that (1) the Plan and the
Options were duly authorized and validly issued by Dyadic-Florida, and (2) each
exercise price for the Options remains, and for the Future Options will be, at
not less than the par value per share of the Common Stock.
<PAGE>

                               Jenkens & Gilchrist
                           A PROFESSIONAL CORPORATION

Dyadic International, Inc.
January 27, 2005
Page 3


      The opinions expressed herein are specifically limited to the laws of the
State of Delaware and the federal laws of the United States of America. We
hereby consent to the filing of this opinion as an exhibit to the Registration
Statement and to references to us included in or made a part of the Registration
Statement. In giving this consent, we do not admit that we come within the
category of persons whose consent is required under Section 7 of the Securities
Act or the Rules and Regulations of the Securities and Exchange Commission
thereunder.

                                              Very truly yours,

                                              Jenkens & Gilchrist,
                                              A Professional Corporation


                                              By: /s/ Daryl B. Robertson
                                                  ----------------------
                                                  Daryl B. Robertson,
                                                  Authorized Signatory

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