<DOCUMENT>
<TYPE>EX-5.1
<SEQUENCE>2
<FILENAME>v10490_ex5-1.txt
<TEXT>

                                                                     Exhibit 5.1


                        Jenkens & Gilchrist                    AUSTIN, TEXAS
                    A PROFESSIONAL CORPORATION                (512) 499-3800

                         1445 ROSS AVENUE                    CHICAGO, ILLINOIS
                            SUITE 3200                        (312) 425-3900
                        DALLAS, TEXAS 75202
                                                              HOUSTON, TEXAS
                          (214) 855-4500                      (713) 951-3300
                     FACSIMILE (214) 855-4300
                                                         LOS ANGELES, CALIFORNIA
                          www.jenkens.com                     (310) 820-8800
                          ---------------
                                                            NEW YORK, NEW YORK
                                                              (212) 704-6000

                                                            SAN ANTONIO, TEXAS
                                                              (210) 246-5000

                                                             WASHINGTON, D.C.
                                                              (202) 326-1500
                         December 29, 2004


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

         Re:      Dyadic International, Inc.
                  Registration Statement on Form SB-2

Ladies and Gentlemen:

         This  firm has  acted as  counsel  to  Dyadic  International,  Inc.,  a
Delaware corporation (the "Company"),  in connection with the preparation of the
Registration  Statement on Form SB-2 (the "Registration  Statement") to be filed
with the Securities and Exchange Commission on or about December 29, 2004, under
the Securities Act of 1933, as amended (the "Securities  Act"),  relating to the
offer and sale of up to 28,369,878 shares (the "Shares") of the Company's common
stock,  par value  $0.001 per share (the  "Common  Stock").  The Shares  offered
include  (i)  20,577,967  presently  outstanding  shares  of Common  Stock  (the
"Stockholders'  Shares"),  (ii) a maximum of 300,300 shares of Common Stock that
may be issued  upon the closing of the  purchase  of real estate  pursuant to an
existing purchase and sale agreement  between the Company and F&C Holdings,  LLC
(the  "Real  Estate  Contract"),  (iii) a maximum of 65,000  shares  that may be
issued upon exercise of certain outstanding stock options (the "Options"),  (iv)
a maximum of 473,835  shares of Common Stock that may be issued upon  conversion
of outstanding  convertible notes (the "Notes"),  and (v) a maximum of 6,952,776
shares of Common Stock that may be issued upon exercise of outstanding  warrants
(the "Warrants").

         You have  requested  the  opinion of this firm with  respect to certain
legal aspects of the proposed offering. In connection  therewith,  this firm has
examined and relied upon the original, or copies identified to our satisfaction,
of (1) the Company's  Restated  Certificate of Incorporation (2) the Amended and
Restated Bylaws of the Company; (3) minutes of the shareholders and the Board of
Directors of the Company (4) the  Registration  Statement and exhibits  thereto;
and (5) such other documents and  instruments as this firm has deemed  necessary
for the expression of these opinions. In making the foregoing examinations, this
firm has assumed the  genuineness of all signatures and the  authenticity of all
documents  submitted to this firm as originals,  and the  conformity to original
documents of all  documents  submitted to this firm as certified or  photostatic
copies. As to various questions of fact material to this opinion letter,  and as
to the  content  and form of the  Restated  Certificate  of  Incorporation,  the
Amended and Restated Bylaws, minutes, records and other documents or writings of
the  Company,   this  firm  has  relied,  to  the  extent  it  deems  reasonably
appropriate,  upon  representations  or certificates of officers or directors of
the Company and upon documents,  records and instruments  furnished to this firm
by the Company, without independent check or verification of their accuracy.

<PAGE>

                               Jenkens & Gilchrist
                           A PROFESSIONAL CORPORATION


Dyadic International, Inc.
December 29, 2004
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.       The  Stockholders'  Shares  have been  legally  issued and are
                  fully paid and  nonassessable  shares of the Company's  Common
                  Stock.

         2.       All corporate  actions  necessary to authorize the issuance by
                  the  Company  of the Shares  upon (i) the  closing of the Real
                  Estate Contract,  (ii) the exercise of the Options,  (iii) the
                  conversion of the Notes and (iv) the exercise of the Warrants,
                  have been duly and validly taken.

         3.       Assuming (i) that all relevant  corporate  actions  heretofore
                  taken by the Company  remain in full force and effect and (ii)
                  that the Shares 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 Real
                  Estate Contract, the Options, the Notes and the Warrants, 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 each exercise  price
for the  Options  and the  Warrants  remains  at not less than the par value per
share of the Common Stock.

<PAGE>

                               Jenkens & Gilchrist
                           A PROFESSIONAL CORPORATION


Dyadic International, Inc.
December 29, 2004
Page 3

         This firm hereby  consents (i) to the reference to us under the caption
"Legal Matters" in the Prospectus,  which constitutes a part of the Registration
Statement  referred to above,  (ii) to the filing of this  opinion  letter as an
exhibit  to the  Registration  Statement  and  (iii) to  references  to our firm
included  in or  made a part  of the  Registration  Statement.  In  giving  this
consent,  this firm does not admit that it comes  within the  category of person
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/ Mark D. Wigder
                                                       -------------------------
                                                       Mark D. Wigder,
                                                       Authorized Signatory


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