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                                                                  Exhibit 10.131

                        CONTRACT MANUFACTURING AGREEMENT


         THIS CONTRACT MANUFACTURING AGREEMENT (the "Agreement") is made this
6th day of November, 1997, by and between Ecogen Inc., a Delaware corporation
("Ecogen") and Archer-Daniels-Midland Company, a Delaware corporation ("ADM").

                               W I T N E S S E T H

         WHEREAS, Ecogen desires to obtain from ADM certain fermentation and
centrifugation services for its Bacillus thuringiensis based ("Bt") biorational
insecticide products and its Aspire yeast product; and

         WHEREAS, ADM as the operator of the Biochem II facility, desires to
provide and operate one seed fermenter, one main fermenter, and one westphalia
centrifuge, plus support equipment, to produce the Products.

         NOW THEREFORE, in consideration of the premises and the mutual
covenants contained herein, it is agreed as follows:

I.       RESPONSIBILITIES

         1.01     ADM shall provide the facility as described in Article II for
                  the production of products as described in Article III (the
                  "Product").

         1.02     In connection with the contract manufacturing of the Products
                  for Ecogen, ADM shall provide the following:

                  (a)      Management, manufacturing and laboratory operations
                           personnel with specific responsibility for the
                           Products;

                  (b)      Utilities;

                  (c)      Maintenance;

                  (d)      Operating permits;

                  (e)      Records of production from process control systems,
                           samples per schedule 1.02(e), shipping records and
                           weigh tickets;

                  (f)      Waste disposal of by-products and failed batches;

                  (g)      Notification to Ecogen should any more toll
                           manufacturing be 


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                           introduced to the facility;

                  (h)      Quality control supervision and shipping of samples;
                           and

                  (i)      Storage of raw materials and cultures.

         1.03     In connection with such contract manufacturing, Ecogen shall
                  provide the following:

                  (a)      Technical personnel when required;

                  (b)      All operating and quality control protocols an
                           example of which is shown on Schedule 1.03(b);

                  (c)      Cultures;

                  (d)      Raw materials (to be purchased from ADM when efficacy
                           is competitive);

                  (e)      Product specifications;

                  (f)      Safety and usage information relative to the raw
                           materials and the Products;

                  (g)      Transportation from the subject facility (ADM
                           Trucking to be used where applicable and
                           competitive); and

                  (h)      Production scheduling.

II.      FACILITY

         2.01     In order to provide the Products, ADM intends to use the
                  facility known as BioChem II when used for producing ADM's own
                  products (the "Facility"). The following equipment at the
                  Facility will be used to produce the Products.

                  (a)      one nominal 21,500 gal fermenter;

                  (b)      one nominal 2,000 gal seed fermenter;

                  (c)      westphalia centrifuge; and

                  (d)      support equipment, as necessary to operate this
                           equipment.

                  If the westphalia centrifuge is down for maintenance, then a
                  second centrifuge will be provided to complete centrifugation
                  before next batch is 


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                  completed.

         2.02     If during the term of this Agreement, Ecogen has product
                  demand which requires additional fermenters and centrifuges
                  and if ADM has available additional fermenters and
                  centrifuges, the parties agree to negotiate in good faith the
                  providing of the second fermenter or centrifuge and a price to
                  do so. Whether a fermenter or centrifuge is considered
                  available is within ADM's sole and absolute discretion.

III.     PRODUCTS

         3.01     Products to be produced by ADM for Ecogen are to be Ecogen's
                  own Bt products and Ecogen's Aspire yeast product.

IV.      TERM OF AGREEMENT

         4.01     The term of this Agreement shall commence on July 1, 1997 (the
                  "Effective Date") and shall continue through December 31, 1999
                  unless earlier terminated in accordance with the provisions of
                  this Agreement. The term of this Agreement shall be extended
                  for additional periods of one year (up to a maximum of five
                  additional years) unless either party provide written notice
                  to the other of its intention to terminate the Agreement, such
                  notice to be given at least eleven months prior to the end of
                  the then current term for ADM, and two months prior to the end
                  of the current term for Ecogen.

         4.02     Ecogen may terminate this Agreement on July 1, 1998, July 1,
                  1999 or December 31, 1999 with two (2) months written notice.

         4.03     In the event of a material breach of this Agreement, the
                  non-breaching party may terminate this Agreement by providing
                  written notice to the other party of the nature of the breach
                  and intent to terminate. Termination will be effective thirty
                  (30) days (ten (10) days in the case of non-payment of an
                  invoice) after such notice unless the breach has been
                  corrected by that time; in the event any such breach can not
                  be reasonably cured within thirty (30) days, the parties may,
                  but need not, agree in writing upon an alternative Schedule to
                  cure such breach.

         4.04     In the event of (i) the institution by or against either party
                  of insolvency, receivership, bankruptcy, or similar
                  proceedings; (ii) either party making an assignment for the
                  benefit of creditors; or (iii) either party's dissolution, the
                  other party may terminate this Agreement by providing written
                  notice to the other party.

V.       PAYMENT

         5.01     ACCESS FEE REIMBURSEMENT. As consideration for the services
                  provided


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                  under this Agreement, Ecogen shall pay to ADM an access fee in
                  the amount of * per year

                  The total amount of the annual access fee is due and owing in
                  advance from Ecogen on July 1 of each year this Agreement is
                  in effect. Payment shall be made monthly in advance in 1/12th
                  increments. Payment is guaranteed by a letter of credit fixed
                  at * and a second letter of credit fixed at * to cover
                  operating cost exposure. During the final six (6) months of
                  the contract the * letter of credit may decline by 1/6th of
                  its value each month.

                  Until the end of 1997 an alternate to a letter of credit would
                  be to prepay service fees also at the estimated usage for the
                  month of fermenter runs, ADM raw materials and CRYMAX dryer
                  pounds.

         5.02     SERVICE FEE REIMBURSEMENT. As consideration for the services
                  provided under this Agreement, ADM shall invoice Ecogen on a
                  monthly basis in arrears for the number of successful batches
                  produced. Successful batches are defined as batches which meet
                  the specifications listed in Schedule 5.02. The exception is
                  that batches which are not successful per Schedule 5.02, but
                  are used (not discarded) are considered successful.

                  (a)      The invoice quantity per batch is * plus the previous
                           months average market price for all raw materials
                           provide from ADM and the actual cost of any other raw
                           materials purchased by ADM. Provided at month's end
                           the average batch gives finished concentrated active
                           ingredient totals in excess of the following:

                           (i)      CRYMAX:  *

                           (ii)     Cutlass:  *

                           (iii)    Lepinox:  *

                           (iv)     Condor:  *

                           (v)      Aspire:  *




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* Confidential Treatment Requested

                  (b)      If the average finished concentrated active
                           ingredient totals per batch is less than the 90%
                           number listed in 5.02(a) (i) - (v) the *


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                           invoice plus the average actual raw material cost
                           defined in 5.02(a) prorated by the ratio of the
                           actual average batch total as the numerator and the
                           standard average shown in 5.02(a) (i) - (iv) as the
                           denominator.

                  (c)      CRYMAX will be billed to Ecogen at * per pound until
                           the drier is moved. Ecogen will use its best efforts
                           to move the drier as soon as possible.

         5.03     INFLATION ADJUSTMENTS. The service fee to be paid by Purchaser
                  for fermentation batches, ordered by Purchaser for delivery
                  after December 31, 1997 shall be determined for each
                  subsequent calendar year by multiplying the Prices set forth
                  in 5.02 by a fraction, the denominator of which is the
                  Producer Price Index figure published for June, 1997 (which
                  the parties agree was 146.9) and the numerator of which is the
                  Producer Price Index published on or most immediately prior to
                  January 1 of the calendar year for which Prices are being
                  determined. The Producer Price Index used shall be the United
                  States Department of Labor, Bureau of Labor Statistics
                  Producer Price Index, Manufacturing Industries, Chemical and
                  Allied Products Group, Code 28 or the successor index thereto.

         5.04     INVOICE PAYMENT TERMS. Ecogen shall make full payment, without
                  setoff, within twenty (20) days from the date of invoice;
                  provided, however, in the event an invoice is disputed, Ecogen
                  shall within said period, pay the undisputed amount and
                  provide ADM with a written position on the disputed portion.

         5.05     Ecogen required improvements to the facility described in 2.01
                  shall be completed by ADM as soon as reasonably possible and
                  shall be paid for by Ecogen when invoiced per section 5.04.

VI.      LICENSE, AND MANUFACTURING RIGHTS

         6.01     Ecogen grants ADM a non-exclusive license to use but no rights
                  to sublicense, during the term of this Agreement, all
                  proprietary rights of Ecogen required by ADM to carry out its
                  obligations under this Agreement.





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* Confidential Treatment Requested


VII.     PERFORMANCE OBLIGATIONS


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         7.01     ADM and Ecogen shall use their best efforts to perform their
                  respective obligations hereunder in a manner which will allow
                  the successful production of Products under this Agreement.

VIII.    TITLE TO PRODUCT

         8.01     Ecogen shall take title to Products at the point such Products
                  are shipped from the Facility.

         8.02     Title to the Facility shall at all times be and remain in ADM.

IX.      LIABILITY

         9.01     ADM shall have no liability for the Products or their use, if
                  any or the performance or activities of its employees provided
                  to Ecogen. Ecogen shall defend, indemnify and hold ADM, its
                  affiliated companies and their respective directors, officers,
                  employees and agents harmless from and against any and all
                  claims, actions, causes of action, judgments, awards,
                  penalties, costs and fees (including reasonable attorneys
                  fees) arising out of the use of or in any way connected with
                  the Products or the operation of the Facility pursuant to this
                  Agreement.

X.       INSURANCE

         10.01    Ecogen shall maintain the certificate of general liability and
                  product liability insurance coverage as shown on Schedule 10
                  or if canceled, provide ADM with another certificate of
                  general liability and product liability insurance evidencing
                  Two Million Dollars ($2,000,000) of coverage with a reputable
                  company or companies. ADM shall be named as an additional
                  insured party on all such policies. In addition, if allowed by
                  law, Ecogen shall cause its workers compensation carrier to
                  waive subrogation against ADM, its affiliated companies and
                  their respective directors, officers, employees and agents.

XI.      FORCE MAJEURE

         11.01    Neither party shall be liable to the other for delay or
                  failure in the performance of its obligations contained in
                  this Agreement to the extent such failure results from any one
                  or more of the following: (a) acts of God, or public enemy or
                  war (declared or undeclared); (b) acts of governmental or
                  quasi-governmental authorities of the United States or any
                  foreign country, or any political subdivision thereof, or of
                  any department or agency thereof, or regulations or
                  restrictions imposed by law or by court action, except as they
                  may result from the unreasonable failure of the party to
                  perform as required hereunder; (c) acts of persons engaged in
                  subversive activities or sabotage; (d) fires, floods,
                  explosions or other


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                  catastrophes; (e) epidemics or quarantine restrictions; (f)
                  strikes, or similar labor disruptions; (g) freight embargoes,
                  or interruption of transportation; (h) unusually severe
                  weather; (i) any other extraordinary causes, similar or
                  dissimilar, beyond the reasonable control of the party
                  concerned; and provided that the due diligence is exercised to
                  cure such cause and resume performance, and the time for
                  performance by such party shall be extended by a period of any
                  such delay. The party affected by force majeure shall promptly
                  notify the other of the existence and expected duration of the
                  force majeure condition.

         11.02    During the term of this Agreement and for the period of five
                  (5) years after the termination or expiration of this
                  Agreement, ADM agrees to treat as confidential all information
                  of Ecogen and its manufacturing partners relative to the
                  Products manufactured by ADM for Ecogen under this Agreement,
                  shall not use such information except as contemplated herein,
                  and shall not disclose such information to any third party,
                  except to the extent that the information (a) was already
                  known to ADM at the time of disclosure by Ecogen, (b) is in or
                  through no fault of ADM enters the public domain, (c) is
                  received without obligations of confidentiality or limited use
                  from a third party having the right to disclose the same to
                  ADM, (d) is independently developed by ADM, or (e) is required
                  to be disclosed pursuant to a valid court order or lawful
                  subpoena provided notice was given to Ecogen in sufficient
                  time for Ecogen to seek a protective order or other relief.

         12.03    During the term of this Agreement and for a period of five (5)
                  years after the termination or expiration of this Agreement,
                  Ecogen agrees to treat as confidential all information of ADM
                  and its manufacturing partners provided to Ecogen by ADM in
                  connection with this Agreement, shall not use such information
                  except as contemplated herein, and shall not disclose such
                  information to any third party, except to the extent that the
                  information (a) was already known to Ecogen at the time of
                  disclosure by ADM, (b) is in or through no fault of Ecogen
                  enters the public domain, (c) is received from a third party
                  having the right to disclose the same to Ecogen, (d) is
                  independently developed by Ecogen, or (e) is required to be
                  disclosed pursuant to a valid court order or lawful subpoena.

XIII.    NOTICE

         13.01    Any notices required or permitted hereunder shall be effective
                  on the mailing thereof if placed in the U.S. mail, certified
                  or registered mail, return receipt requested and deposited
                  postage prepaid, addressed to:

                       ADM:       Archer-Daniels-Midland Company
                                  P.O. Box 1470
                                  Decatur, IL  62525
                                  Attention:  President, Bio-Products Division


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                       with a copy to:

                                  Archer-Daniels-Midland Company
                                  P.O. Box 1470
                                  Decatur, IL  62525
                                  Attention: General Counsel

                                  Ecogen:  Ecogen Inc.
                                  2005 Cabot Boulevard West
                                  Langhorne, PA 19047
                                  Attention: President

                       with a copy to:

                                  Ecogen Inc.
                                  2005 Cabot Boulevard West
                                  Langhorne, PA  19047
                                  Attention: General Counsel

XIV.     ASSIGNMENT

         14.01    This Agreement will be binding and inure to the benefit of the
                  parties hereto and their respective successors and assigns. No
                  assignment (including assignment by operation of law),
                  delegation or other use of any right or duty under this
                  Agreement may be made by either party without the written
                  consent of the other party, except that either party may at
                  any time assign and delegate its mutual rights and duties to a
                  purchaser of all or substantially all of its stock or assets
                  or to the surviving entity in a merger, consolidation or other
                  corporate reorganization in which the party participates, as
                  long as such surviving entity or purchaser shall expressly
                  assume in writing the performance of this Agreement.

XV.      SEVERABILITY.

         15.01    If any part of this Agreement is found invalid or
                  unenforceable, that part will be amended to achieve, as nearly
                  as possible, the same economic effect as the original
                  provision and the remainder of this Agreement shall remain in
                  full force.



XVI.     GOVERNING LAW.

         16.01    This Agreement shall be governed by and construed in
                  accordance with the laws of the State of Illinois, excluding
                  any conflict of law principles of the State of Illinois which
                  may require the application of the laws of another
                  jurisdiction. The courts of the State of Illinois, the
                  personal 


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                  jurisdiction to which each of the parties of this Agreement
                  voluntarily submits, shall have the exclusive jurisdiction to
                  hear and decide any dispute or controversy concerning this
                  Agreement.

XVII.    ARBITRATION.

         17.01    In the event of a dispute between the parties arising out of
                  this Agreement or any part of it, or their performance under
                  it, the dispute shall be submitted to binding arbitration in
                  Chicago, Illinois, in accordance with the Commercial Rules
                  then in effect of the American Arbitration Association.

XVIII.   ANNOUNCEMENTS.

         18.01    Neither party shall make any announcements relative to the
                  Agreement without the prior written consent of the other party
                  except as required by law.

XIX.     Entire Agreement.

         19.01    This Agreement constitutes the entire agreement between the
                  parties relating to this subject matter and supersedes all
                  prior agreements and understandings. This Agreement cannot be
                  amended or modified except in writing duly executed by each
                  party.


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


                                ARCHER-DANIELS-MIDLAND COMPANY


                                By:  /s/ Brian Peterson
                                   -------------------------------------
                                     Brian Peterson



                                ECOGEN INC.

                                By:  /s/ James P. Reilly, Jr.
                                   -------------------------------------
                                     James P. Reilly, Jr.
                                     Chairman & Chief Executive Officer


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