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                                                                 EXHIBIT 10.22

WHENEVER CONFIDENTIAL INFORMATION IS OMITTED HEREIN (SUCH OMISSIONS ARE DENOTED
BY AN ASTERISK*), SUCH CONFIDENTIAL INFORMATION HAS BEEN SUBMITTED SEPARATELY TO
THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL
TREATMENT.



                               FIRST AMENDMENT TO
                   TECHNOLOGY ALLIANCE AND OPTION AGREEMENT


         This First Amendment to Technology Alliance and Option Agreement
(this "Amendment") dated as of September 8, 2005 (the "Effective Date") is by
and between ADM Polymer Corporation, a corporation duly incorporated and
validly existing under the laws of the State of Delaware, with headquarters
located at 4666 Faries Parkway, Decatur, IL 62526 ("ADM Sub"), and Metabolix,
Inc., a corporation duly incorporated and validly existing under the laws of
the State of Delaware, with headquarters located at 21 Erie Street,
Cambridge, MA 02139-4260 ("MBX") (MBX and ADM Sub are collectively the
"Parties" and each is a "Party").

                                    RECITALS

         WHEREAS, MBX and ADM Sub entered into that certain Technology Alliance
and Option Agreement dated as of November 4, 2004 (the "Agreement"); and

         WHEREAS, MBX and ADM Sub now desire to modify the terms of the
Agreement as set forth herein.

         NOW, THEREFORE, in consideration of the recitals and the mutual
covenants and promises contained herein, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
Parties hereto do hereby agree as follows:

                                    ARTICLE 1
                                   DEFINITIONS

         1.1 DEFINITIONS. Capitalized terms used but not defined herein shall
have the meaning ascribed to them in the Agreement.

                                    ARTICLE 2
                        AMENDMENTS AND ADDITIONS TO TERMS

         2.1 AMENDMENT TO ARTICLE 1. Article 1 of the Agreement is hereby
amended by deleting the existing definition for "Fermentation Performance
Parameters" and replacing it with the following text:

                  "FERMENTATION PERFORMANCE PARAMETERS" means the various
         parameters for production of PHA Cell Paste through fermentation at the
         * scale as set forth on AMENDED EXHIBIT B.


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         2.2 AMENDMENT OF SECTION 3.1. The Agreement is hereby amended by
deleting the existing Section 3.1 in its entirety and replacing it with the
following text:

                  "3.1 GOAL OF TECHNOLOGY ALLIANCE PROGRAM. The goal of
         the Technology Alliance Program is to (i) produce PHA Cell Paste, in a
         fermenter having a capacity of approximately *, and at ADM Sub's option
         then in a fermenter having a capacity of approximately *, in all cases,
         in a manner and with results that meet the applicable Fermentation
         Performance Parameters; (ii) demonstrate recovery of PHA Material in a
         manner and with results that meet the Recovery Performance Parameters
         (the items listed in the foregoing "(i)" and "(ii)" collectively are
         the "Technical Aspects of the Goal"); and (iii) based upon the results
         of (i) and (ii) above, have ADM Sub develop and the TAC agree upon a
         completed master plan for Construction of the ADM Sub Manufacturing
         Facility, including without limitation, surveys, blueprints, and
         engineering studies, which master plan shall be organized into a
         detailed, multiphase process for undertaking and completing
         Construction of the ADM Sub Manufacturing Facility and which shall have
         a project budget with projected detailed expenditures provided for each
         phase of the Construction process, all of which shall be, in form and
         substance, suitable for ADM Sub's management and board of directors to
         make a determination to approve the expenditures for the ADM Sub
         Manufacturing Facility as and to the extent required by ADM Sub's
         corporate governance polices and procedures (the "ADM Sub Construction
         Master Plan and Budget") (collectively the "Goal"). Successful
         completion of the Goal is intended to confirm the potential economics
         of producing PHA Material at commercial scale as part of a long-term
         commercial alliance."

         2.3 ADDITION OF SECTION 3.2.4.1. The Agreement is hereby amended by
adding the following Section 3.2.4.1:

                  "3.2.4.1 INITIAL RECOVERY OPERATIONS. The Parties hereby agree
         that MBX will enter into an agreement to obtain access to toll recovery
         services, from a Third Party (the "Toll Producer") on substantially the
         terms set forth in the tolling agreement attached hereto as Schedule A
         (the "Tolling Agreement"). These recovery services are anticipated to
         last until approximately March of 2006 and to result in the recovery of
         up to approximately thirty five (35) metric tons of PHA Material (the
         "Initial Recovery Services"). Except as specifically set forth herein,
         the Parties' rights and obligations with respect to the Initial
         Recovery Services and the PHA Material produced in connection therewith
         shall be governed by the Agreement as activities conducted under
         Section 3.2.4. Responsibility for the fees charged by the Toll Producer
         under the Tolling Agreement for the Initial Recovery Services, related
         equipment and capital expenses, and the reasonable out-of-pocket
         expenses of the Parties in performing technical support or auditing of
         the Initial Recovery Services, including, for example, travel and
         lodging expenses, but excluding, salary and benefits paid or payable to
         employees or representatives of the Parties participating in such
         activities (collectively, "Tolling Expenses") shall be shared equally
         by the Parties, subject to the limitations set forth herein. The
         Parties shall, determine reasonable


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         methods for promptly accounting for the total Tolling Expenses on a
         monthly basis and making such payments as are necessary in order to
         give effect to the equal sharing of the Tolling Expenses.
         Notwithstanding the foregoing: (i) MBX shall be solely responsible for
         the operating expenses (including its internal costs and the costs of
         the Toll Producer but excluding the related equipment and capital
         expenses) until (y) the earlier of TAC's determination that the
         recovery of PHA Material during a Recovery Campaign was achieved in a
         manner and with results that met the Recovery Performance Parameters as
         defined in Amended Exhibit E on any one of the three specified
         compositions, or ADM Sub's payment of the milestone payment set forth
         in Section 5.1 related to the Recovery Performance Parameters, and (z)
         ADM's receipt of a letter from the U.S. Drug Enforcement Administration
         advising that polyhydroxyalkanoate containing gamma-hydroybutyric acid
         as part of the polymer chain will not be regulated as a controlled
         substance under the Controlled Substances Act and any Drug Enforcement
         Administration regulations, (ii) ADM shall not be obligated to pay in
         excess of * of Tolling Expenses hereunder; (iii) ADM shall not be
         obligated to pay in excess of * of the equipment and capital expenses
         comprising the Tolling Expenses hereunder; and (iv) ADM shall not be
         responsible for any Tolling Expenses incurred after the end of the term
         of this Agreement as set forth in Section 8.1, except as otherwise
         provided under the Commercial Alliance Agreements, if applicable. In
         the event ADM terminates this Agreement or decides not to exercise the
         Option, then MBX shall pay ADM an amount equal to one half of the
         depreciated book value of any removable assets (i.e., not fixtures)
         that are listed on the Consignment Agreement or any Addendum to
         Consignment Agreement (as such agreement and such addendum are
         referenced in the Tolling Agreement), the purchase price for which was
         funded equally by the Parties. MBX agrees to provide ADM with equal
         access to the facility of the Toll Producer as and to the extent such
         access is made available to MBX and its designees under the Tolling
         Agreement. The PHA Material produced in connection with the Initial
         Recovery Services shall be part of the Technology Alliance Output or
         Marketing Material as determined under Section 3.3, and, in the event
         it is sold by MBX, all revenues generated by such sales shall be
         applied against Tolling Expenses before such expenses are allocated for
         payment by the Parties. The Parties agree to work together to determine
         the costs (capital expenditures and operating costs) to use ADM's
         Vitamin C facility for pilot sourcing of PHA Material in the event ADM
         exercises the Option; PROVIDED, HOWEVER, nothing herein shall preclude
         ADM from utilizing all or any portion of the Vitamin C facility for
         other uses."

         2.4 AMENDMENT OF SECTION 3.3. The Agreement is hereby amended by
deleting the existing Section 3.3 in its entirety and replacing it with the
following text:

                  "3.3 OUTPUT FROM TECHNOLOGY ALLIANCE PROGRAM. ADM Sub
         will use Commercially Reasonable Efforts to produce PHA Cell Paste in
         such amounts as result from the operations set forth in the Technology
         Alliance Plan until it has satisfied the Fermentation Performance
         Parameters (the "Technology Alliance Output") and such additional
         amounts thereafter as the Parties may agree to in


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         writing (the "Marketing Material") for use by MBX in developing the
         market for PHA Material. The Technology Alliance Output and the
         Marketing Material will be made available by ADM Sub to MBX as set
         forth in this Section 3.3."


         2.5 AMENDMENT OF SECTION 3.3.1. The Agreement is hereby amended by
deleting the existing Section 3.3.1 in its entirety and replacing it with the
following text:

                  "3.3.1 ANALYSIS OF TECHNOLOGY ALLIANCE OUTPUT. MBX
         will use the Technology Alliance Output to demonstrate recovery of PHA
         Material in accordance with Section 3.2.4 and the Technology Alliance
         Plan, and ADM shall provide the Technology Alliance Output to MBX as
         MBX may require to perform such recovery demonstration, including the
         Initial Recovery Services. Further, the Technology Alliance Output will
         be used by the Parties to perform such evaluation and analysis as is
         necessary or useful in determining whether the Parties have achieved
         the Goal. Without limiting the foregoing statement, the Technology
         Alliance Output will be evaluated and analyzed by the Parties, in
         accordance with the procedures and methods set forth in the Technology
         Alliance Plan, to determine whether the Technology Alliance Output
         meets the Fermentation Performance Parameters and whether PHA Material
         recovered from the Technology Alliance Output meets the Recovery
         Performance Parameters."

         2.6 AMENDMENT OF SECTION 3.3.2. The Agreement is hereby amended by
deleting the existing Section 3.3.2 in its entirety and replacing it with the
following text:

                  "3.3.2 PURCHASE OF TECHNOLOGY ALLIANCE OUTPUT BY MBX;
         COST SHARING FOR MARKETING MATERIAL. MBX shall have the right, but not
         the obligation, to purchase the Technology Alliance Output that is not
         required to perform the recovery demonstration described in Section
         3.3.1 above from ADM Sub at a price of * of PHA Material contained
         within the PHA Cell Paste, on a one hundred percent (100%) purity
         basis; provided such price shall be reduced to * at such times as ADM
         is responsible for equally sharing the Tolling Expenses (including the
         operating expenses) pursuant to Section 3.2.4.1. MBX shall purchase the
         Marketing Material, irrespective of whether the Marketing Material
         meets the applicable specifications or not, at fifty percent (50%) ADM
         Sub's Manufacturing Cost, F.O.B. Decatur, Illinois. MBX may exercise
         this purchase option at any time, and from time-to-time, during the
         Technology Alliance Program and up to thirty (30) days after the
         expiration or termination of the Technology Alliance Program, by
         written notice to ADM Sub, stating its desire to purchase, the quantity
         to be purchased (up to the total amount that is then available) and
         shipping and delivery instructions. ADM Sub shall invoice MBX for
         amounts so purchased no sooner than at the time of delivery and the
         purchase price for amounts ordered and delivered in accordance herewith
         shall be payable by MBX within thirty (30) days of receipt of an
         invoice from ADM Sub by wire transfer of immediately available funds to
         an account in the United States designated by ADM Sub. Technology
         Alliance Output and Marketing Material purchased hereunder shall be
         purchased "as is," without warranty of any kind other than that the
         Technology Alliance Output and Marketing Material shall have


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         been stored and handled, from the time of production until the delivery
         to MBX, in accordance with the requirements of the Technology Alliance
         Plan or as otherwise agreed by the Parties. Technology Alliance Output
         and Marketing Material purchased by MBX shall be used by MBX for
         performing its obligations pursuant to this Agreement and for market
         development activities benefiting the Parties and the potential
         Commercial Alliance between them. Technology Alliance Output that is
         not purchased by MBX shall be used by ADM Sub solely for internal
         research and development purposes, or if not so used, ADM Sub shall
         either store (for later sale to MBX or the Joint Sales Company or for
         later use by ADM Sub solely for internal research purposes) or dispose
         of the unused Technology Alliance Output, at ADM Sub's option."

         2.7 AMENDMENT OF SECTION 4.3. The Agreement is hereby amended by
deleting the existing Section 4.3 in its entirety and replacing it with the
following text:

                  "4.3 GRANT OF OPTION. MBX hereby grants to ADM Sub the right
         and option to enter into a commercial alliance for the further
         research, development, manufacture, use, sale and importation of the
         PHA Material and PHA Formulations on the terms and conditions set forth
         in the Commercial Alliance Agreements (the "Option"). The Option shall
         be exercisable by ADM Sub at any time after Effective Date and until
         thirty (30) days after the expiration of the term of this Agreement, by
         written notice to MBX; PROVIDED, HOWEVER, that, in either case, the
         Option shall not be exercisable if and for so long as ADM Sub is in
         breach of this Agreement. Following the exercise of the Option, the
         Parties shall promptly execute and deliver the Commercial Alliance
         Agreements in accordance with this Agreement."

         2.8 AMENDMENT OF SECTION 5.1. The Agreement is hereby amended by
deleting the existing Section 5.1 in its entirety and replacing it with the
following text:

                  "5.1 PAYMENTS. Within ten (10) days after the Effective Date,
         ADM Sub shall pay to MBX the amount of * as a non-refundable,
         non-creditable upfront payment. Within ten (10) days following the
         TAC's determination that the production of PHA Cell Paste in a
         fermenter having a capacity of approximately * was achieved in a manner
         and with results that met the applicable Fermentation Performance
         Parameters, ADM Sub shall pay to MBX the amount of * as a
         non-refundable, non-creditable milestone payment. Within ten (10) days
         following the TAC's determination that the recovery of PHA Material was
         achieved in a manner and with results that met the Recovery Performance
         Parameters, ADM Sub shall pay to MBX the amount of * as a
         non-refundable, non-creditable milestone payment. Within ten (10) days
         following the first to occur of: (i) the achievement of the Goal and
         (ii) the exercise of the Option by ADM Sub, ADM Sub shall pay to MBX
         the amount of * as a non-refundable, non-creditable milestone payment.
         Anything herein to the contrary notwithstanding, in the event that ADM
         Sub desires to exercise the Option in accordance with Section 4.3, the
         above-described upfront payment and the three (3) milestone payments,
         to the extent not already paid, shall be due and


* CONFIDENTIAL TREATMENT REQUESTED


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         payable in full as a pre-condition to the exercise of the Option.
         Amounts due under this Section 5.1 shall be payable by wire transfer of
         immediately available funds to an MBX bank account in accordance with
         instructions to be provided to ADM Sub by MBX."

         2.9 AMENDMENT OF SECTION 5.2. The Agreement is hereby amended by
deleting the existing Section 5.2 in its entirety and replacing it with the
following text:

                  "5.2 OTHER EXPENSES. Except as provided in Section 5.1,
         Section 3.2.4.1 and Section 3.3.2, each Party shall bear its own costs
         and expenses incurred in performing under this Agreement."

         2.10 AMENDMENT OF EXHIBITS. The Agreement is hereby amended by deleting
the existing Exhibit B and replacing it with the text set forth in Amended
Exhibit B attached hereto, by deleting existing Exhibit D and replacing it with
the text set forth in Amended Exhibit D attached hereto, and by deleting the
existing Exhibit E and replacing it with the text set forth in Amended Exhibit E
attached hereto.

                                    ARTICLE 3
                              CONFIRMATION OF TERMS

         3.1 CONFIRMATION OF TERMS. This Amendment shall be a part of the
Agreement and shall be governed in accordance with the terms and conditions set
forth therein, as the same are amended hereby, including without limitation, the
terms and conditions set forth in Article XI of the Agreement, entitled
"Miscellaneous." The Parties hereby agree and acknowledge that, except as
expressly set forth herein, the Agreement shall remain in full force and effect
in accordance with its terms.


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         IN WITNESS WHEREOF, the Parties hereto have caused this Amendment to be
executed by their duly authorized representatives as of the day and year above
written.


                                       ADM POLYMER CORPORATION


                                       By: /s/ JOHN D. RICE
                                           ------------------------------------
                                       Name:  John D. Rice
                                       Title: President


                                       METABOLIX, INC.


                                       By: /s/ JAMES J. BARBER
                                           ------------------------------------
                                       Name:  James J. Barber
                                       Title: President


* CONFIDENTIAL TREATMENT REQUESTED