EXHIBIT 99.1
                                      ISCO, INC.
                                         1996
                                  STOCK OPTION PLAN


 1. NAME.

    The name of this Plan is the Isco, Inc. 1996 Stock Option Plan. 

 2. DEFINITIONS.

    For the purposes of the Plan, the following terms shall be defined as set
    forth below:

    a.   "Affiliate" means any partnership, corporation, firm, joint venture,
         association, trust, limited liability company, unincorporated
         organization or other entity (other than a Subsidiary) that, directly
         or indirectly through one or more intermediaries, is controlled by the
         Company, where the term "controlled by" means the possession, direct
         or indirect, of the power to cause the direction of the management and
         policies of such entity, whether through the ownership of voting
         interests or voting securities, as the case may be, by contract or
         otherwise.

    b.   "Board" means the board of directors of the Company.

    c.   "Cause" as applied to any Officer or Employee means: (i) the
         conviction of such individual for the commission of any felony; (ii)
         the commission by such individual of any crime involving moral
         turpitude (E.G., larceny, embezzlement) which results in harm to the
         business, reputation, prospects or financial condition of the Company,
         any Subsidiary or Affiliate; or (iii) a disciplinary discharge
         pursuant to the terms of the Company's management handbooks as in
         effect at the time. 

    d.   "Chairman" means the individual appointed by the Board to serve as the
         chairman of the Committee.

    e.   "Code" means the Internal Revenue Code of 1986, as amended from time
         to time and the Treasury regulations promulgated thereunder.

    f.   "Committee" means the committee appointed by the Board to administer
         the Plan as provided in Section 4(a).

    g.   "Common Stock" means the Common Stock, $0.10 par value per share, of
         the Company or any security of the Company identified by the Committee
         as having been issued in substitution or exchange therefor or in lieu
         thereof.

    h.   "Company" means Isco, Inc., a Nebraska corporation.

    i.   "Employee" means an individual employed by the Company or a Subsidiary
         whose wages are subject to the withholding of federal income tax under
         Section 3401 of the Code. 

    j.   "Exchange Act" means the Securities Exchange Act of 1934, as amended
         from time to time, or any successor statute.

    k.   "Fair Market Value" of a Share as of a specified date means the
         average of the highest and lowest market prices of a Share on the
         NASDAQ 


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         National Market System on such date as reported in the Midwestern 
         Edition of THE WALL STREET JOURNAL or, if no trading of Common Stock is
         reported for that day, the next preceding day on which trading was 
         reported.  In the event the Common Stock is not then traded on the 
         NASDAQ National Market System, the Fair Market Value of a Share shall
         be determined by reference to the principal market or exchange on which
         the Common Stock is then traded.

    l.   "Incentive Stock Option" (otherwise designated as an ISO) means any
         stock option granted pursuant to the Plan that is intended to be and
         is specifically designated as an "Incentive Stock Option" within the
         meaning of Section 422 of the Code.

    m.   "Non-qualified Stock Option" (otherwise designated as a NQSO) means
         any stock option granted pursuant to the provisions of the Plan that
         is not an ISO.

    n.   "Officer" means an individual elected or appointed by the Board or by
         the board of directors of a Subsidiary or chosen in such other manner
         as may be prescribed by the Bylaws of the Company or a Subsidiary, as
         the case may be, to serve as such.

    o.   "Option" means an ISO or a NQSO granted under the Plan.

    p.   "Participant" means an individual who is granted an Option under the
         Plan. 

    q.   "Plan" means this 1996 Stock Option Plan.

    r.   "Rule 16b-3" means Rule 16b-3 promulgated by the Securities and
         Exchange Commission under the Exchange Act, or any successor or
         replacement rule adopted by the Securities and Exchange Commission.

    s.   "Share" means one share of Common Stock, adjusted in accordance with
         Section 10(b) of the Plan, if applicable.

    t.   "Stock Option Agreement" means the written agreement between the
         Company and the Participant that contains the terms and conditions
         pertaining to an Option.

    u.   "Subsidiary" means any corporation of which the Company, directly or
         indirectly, is the beneficial owner of fifty percent (50%) or more of
         the total voting power of all classes of its stock having voting power
         and which qualifies as a subsidiary corporation pursuant to Section
         424(f) of the Code.

    v.   "Ten Percent Stockholder" means a Participant who prior to the grant
         of an ISO owned, directly or indirectly within the meaning of Section
         424(d) of the Code, ten percent (10%) or more of the total combined
         voting power of all classes of stock of the Company, any Subsidiary or
         any parent of the Company (as defined in Section 425(e) of the Code).

 3. PURPOSE.

    The purpose of the Plan is to enable the Company to provide incentives,
    which are linked directly to increases in stockholder value, to certain key
    personnel in order that they will be encouraged to promote the financial
    success and progress of the Company.


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 4. ADMINISTRATION.

    a.   COMPOSITION OF THE COMMITTEE.

         The Plan shall be administered by a Committee appointed by the Board,
         consisting of not less than two "Non-Employee Directors"  (as such
         term is defined in Rule 16b-3), to be a director who is not currently
         an officer or otherwise employed by the issuer, or a parent or
         subsidiary of the issuer; does not receive compensation directory or
         indirectly from the issuer, its parent or subsidiary for services
         rendered as a consultant or in any capacity other than as a director,
         (except for an amount less than $60,000); does not possess an interest
         in any other transaction for which disclosure would be required
         pursuant to Item 404(a) of Regulation S-K; and is not engaged in a
         business relationship for which disclosure would be required pursuant
         to Item 404(b) of Regulation S-K.  In the event the Company is, at any
         time unable to qualify a Committee of two or more Non-Employee
         Directors, the Plan shall be administered by the Board.  Subject to
         the provisions of the first sentence of this Section 4(a), the Board
         may from time to time remove members from, or add members to, the
         Committee.  Vacancies on the Committee, however caused, shall be
         filled by the Board.  The Board shall appoint one of the members of
         the Committee as Chairman.  

    b.   ACTIONS BY THE COMMITTEE.

         The Committee shall hold meetings at such times and places as it may
         determine.  Acts approved by a majority of the members of the
         Committee present at a meeting at which a quorum is present, or acts
         reduced to or approved in writing by a majority of the members of the
         Committee, shall be the valid acts of the Committee.

    c.   POWERS OF THE COMMITTEE.

         Subject to the express terms and conditions hereof, the Committee
         shall have the authority to administer the Plan in its sole and
         absolute discretion.  To this end, the Committee is authorized to
         construe and interpret the Plan and to make all other determinations
         necessary or advisable for the administration of the Plan, including,
         but not limited to, the authority to determine the eligible
         individuals who shall be granted Options, the number of Options to be
         granted, the vesting period, if any, for all Options granted
         hereunder, the date on which any Option becomes first exercisable, the
         number of Shares subject to each Option, the exercise price for the
         Shares subject to each Option, and, whether the Option to be granted
         is an ISO or a NQSO.  Any determination, decision or action of the
         Committee in connection with the construction, interpretation,
         administration or application of the Plan shall be final, conclusive
         and binding upon all Participants and any person validly claiming
         under or through a Participant.

    d.   LIABILITY OF COMMITTEE MEMBERS.

         No member of the Board or the Committee will be liable for any action
         or determination made in good faith by the Board or the Committee with
         respect to the Plan or any grant or exercise of an Option thereunder.

    e.   OPTION ACCOUNTS.

         The Committee shall maintain a journal in which a separate account for
         each Participant shall be established.  Whenever an Option is granted
         to or exercised by a Participant, the Participant's account shall be 


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    appropriately credited or debited.  Appropriate adjustment shall also be
    made in the journal with respect to each account in the event of an
    adjustment pursuant to Section 10(b) of the Plan.

 5. EFFECTIVE DATE AND TERM OF THE PLAN.

    a.   EFFECTIVE DATE OF THE PLAN.

         The Plan was adopted by the Board and became effective on September
         19, 1996, subject to approval by the stockholders of the Company at a
         meeting duly called and held within twelve months following such date.

    b.   TERM OF PLAN.

         No Option shall be granted pursuant to the Plan on or after September
         19, 2006, but Options theretofore granted may extend beyond that date.

 6. TYPE OF OPTIONS AND SHARES SUBJECT TO THE PLAN.

    Options granted under the Plan may be either ISOs or NQSOs.  Each Stock
    Option Agreement shall specify whether the Option covered thereby is an ISO
    or a NQSO.

    The maximum aggregate number of Shares that may be issued under the Plan is
    250,000 Shares.  Up to and including all 250,000 Shares reserved for
    issuance under the Plan may be designated as ISOs.  The limitation on the
    number of Shares which may be subject to Options under the Plan shall be
    subject to adjustment as provided in Section 10(b) of the Plan.

    If any Option granted under the Plan expires or is terminated for any
    reason, any Shares as to which the Option has not been exercised shall
    again be available for purchase under Options subsequently granted.  At all
    times during the term of the Plan, the Company shall reserve and keep
    available for issuance such number of Shares as the Company is obligated to
    issue upon the exercise of all then outstanding Options.

 7. SOURCE OF SHARES ISSUED UNDER THE PLAN.

    Common Stock issued under the Plan shall be authorized and unissued Shares
    and/or Treasury Shares.  No fractional Shares shall be issued under the
    Plan.

 8. ELIGIBILITY.

    The individuals eligible for the grant of Options under the Plan shall be: 
    (i) all  Officers and Employees; and (ii) such individuals determined by
    the Committee to be rendering substantial services as a consultant or
    independent contractor to the Company or any Subsidiary or Affiliate of the
    Company, as the Committee shall determine from time to time in its sole and
    absolute discretion; PROVIDED, HOWEVER, that only Employees of the Company
    or any Subsidiary shall be eligible to receive ISOs.  Any Participant shall
    be eligible to be granted more than one Option hereunder.

 9. OPTIONS.

    a.   GRANT OF OPTIONS.

         Subject to any applicable requirements of the Code and any regulations
         issued thereunder, the date of the grant of an Option shall be the
         date on which the Committee determines to grant the Option.


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    b.   EXERCISE PRICE OF ISOs.

         The exercise price of each Share subject to an ISO shall not be less
         than the Fair Market Value of a Share on the date of grant of the ISO,
         except that in the case of a grant of an ISO to a Participant who at
         the time such ISO was granted was a Ten Percent Stockholder, the
         exercise price shall not be less than 110% of the Fair Market Value of
         a Share on the date of the grant of the ISO.

    c.   EXERCISE PRICE OF NQSOs.

         The exercise price of each Share subject to a NQSO shall be determined
         by the Committee at the time of grant but will not be less than
         eighty-five percent (85%) of the Fair Market Value of a Share on the
         date of grant.

    d.   EXERCISE PERIOD.

         Each Option granted hereunder shall vest and become first exercisable
         as determined by the Committee.

    e.   TERMS AND CONDITIONS.

         All Options granted pursuant to the Plan shall be evidenced by a Stock
         Option Agreement (which need not be the same for each Participant or
         Option), approved by the Committee which shall be subject to the
         following express terms and conditions and the other terms and
         conditions as are set forth in this Section 9, and to such other terms
         and conditions as shall be determined by the Committee in its sole and
         absolute discretion which are not inconsistent with the terms of the
         Plan:

         i.   the failure of an Option to vest for any reason whatsoever shall
              cause the Option to expire and be of no further force or effect;

         ii.  unless terminated earlier pursuant to Sections 9(i) or 11, the
              term of any Option granted under the Plan shall be ten years from
              the date of grant; PROVIDED, HOWEVER, that no ISO granted to a
              Ten Percent Stockholder shall have a term of more than five years
              from the date of grant;

         iii. in the case of an ISO, the aggregate Fair Market Value
              (determined as of the time the ISO is granted) of Shares
              exercisable for the first time by a Participant during any
              calendar year (under the Plan and any other incentive stock
              option plans of the Company, any Subsidiary or any parent of the
              Company (as defined in Section 424(e) of the Code) shall not
              exceed $100,000;

         iv.  Options shall not be transferable by the Participant otherwise
              than by will or by the laws of descent and distribution, and
              shall be exercisable during the lifetime of the Participant only
              by him or by his guardian or legal representative;

         v.   no Option or interest therein may be transferred, assigned,
              pledged or hypothecated by the Participant during his lifetime
              whether by operation of law or otherwise, or be made subject to
              execution, attachment or similar process; and


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         vi.  payment for the Shares to be received upon exercise of an Option
              may be made in cash, in Shares (determined with reference to
              their Fair Market Value on the date of exercise) or any
              combination thereof.

    f.   EXERCISE.

         The holder of an Option may exercise the same by filing with the
         Corporate Secretary of the Company and the Chairman a written
         election, in such form as the Committee may determine, specifying the
         number of Shares with respect to which such Option is being exercised,
         and accompanied by payment in full of the exercise price for such
         Shares.  Notwithstanding the foregoing, the Committee may specify a
         reasonable minimum number of Shares that may be purchased on any
         exercise of an Option, provided that such minimum number will not
         prevent the holder from exercising the Option with respect to the full
         number of Shares as to which the Option is then exercisable.

    g.   WITHHOLDING TAXES.

         Prior to issuance of the Shares upon exercise of an Option, the
         Participant shall pay or make adequate provision for the payment of
         any Federal, state, local or foreign withholding obligations of the
         Company or any Subsidiary or Affiliate of the Company, if applicable. 
         In the event a Participant shall fail to make adequate provision for
         the payment of such obligations, the Company shall have the right to
         issue a stock certificate for an amount of Shares equal to the
         difference obtained by subtracting: (i) the number of Shares, rounded
         up for any fraction to the next whole number, that have a Fair Market
         Value (as of the date of exercise) equal to such amount as is
         sufficient to satisfy applicable federal, state or local withholding
         obligations; from (ii) the number of Shares attributable to that
         portion of the Option so exercised.  The Company shall promptly remit,
         or cause to be remitted, to the appropriate taxing authorities the
         amount so withheld.  In such cases, although the stock certificate
         delivered to the Participant will be for a net number of Shares, such
         Participant shall be considered, for tax purposes, to have received
         the number of Shares equal to the full number of Shares to which the
         Option had been exercised.

    h.   TERMINATION OF OPTIONS.

         Options granted under the Plan shall be subject to the following
         events of termination:

         i.   in the event the employment of a Participant who is an Officer or
              Employee is terminated for Cause, all unexercised Options held by
              such Participant on the date of such termination of employment
              (whether or not vested) will expire immediately; and

         ii.  in the event a Participant is no longer an Officer or Employee
              other than for the reasons set forth in Sections 9(i)(i) or
              9(i)(ii), all Options which remain unvested at the time the
              Participant is no longer a Director, Officer or Employee, as the
              case may be, shall expire immediately, and all Options which have
              vested prior to such time shall expire twelve months thereafter
              unless by their terms they expire sooner.


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10. RECAPITALIZATION.

    a.   CORPORATE FLEXIBILITY.

         The existence of the Plan and the Options granted hereunder shall not
         affect or restrict in any way the right or power of the Board or the
         stockholders of the Company, in their sole and absolute discretion, to
         make, authorize or consummate any adjustment, recapitalization,
         reorganization or other change in the Company's capital structure or
         its business, any merger or consolidation of the Company, any issue of
         bonds, debentures, Common Stock, preferred or prior preference stock
         ahead of or affecting the Company's capital stock or the rights
         thereof, the dissolution or liquidation of the Company or any sale or
         transfer of all or any part of its assets or business, or any other
         grant of rights, issuance of securities, transaction, corporate act or
         proceeding and notwithstanding the fact that any such activity,
         proceeding, action, transaction or other event may have, or be
         expected to have, an impact (whether positive or negative) on the
         value of any Option.

    b.   ADJUSTMENTS UPON CHANGES IN CAPITALIZATION.

         Except as otherwise provided in Section 11 and subject to any required
         action by the stockholders of the Company, in the event of any change
         in capitalization affecting the Common Stock of the Company, such as a
         stock dividend, stock split or recapitalization, the Committee, in its
         sole and absolute discretion, may make proportionate adjustments with
         respect to:  (i) the aggregate number of Shares available for issuance
         under the Plan; (ii) the number of Shares available for any individual
         award; (iii) the number and exercise price of Shares subject to
         outstanding Options; PROVIDED, HOWEVER, that the number of Shares
         subject to any Option shall always be a whole number; and (iv) such
         other matters as shall be appropriate in light of the circumstances.

11. CHANGE OF CONTROL.

    In the event of a Change of Control (as defined below), unless otherwise
    determined by the Committee at the time of grant or by amendment (with the
    holder's consent) of such grant, all Options not vested on or prior to the
    effective time of any such Change of Control shall immediately vest as of
    such effective time.  The Committee in its discretion may make provisions
    for the assumption of outstanding Options, or the substitution for
    outstanding Options of new incentive awards covering the stock of a
    successor corporation or a parent or subsidiary thereof, with appropriate
    adjustments as to the number and kind of shares and prices so as to prevent
    dilution or enlargement of rights.

    A "Change of Control" will be deemed to occur on the date any of the
    following events occur:

    a.   any person or persons acting together which would constitute a "group"
         for purpose of Section 13(d) of the Exchange Act (other than the
         Company, any Subsidiary and any entity beneficially owned by any of
         the foregoing) beneficially own (as defined in Rule 13d-3 under the
         Exchange Act) without Board approval, directly or indirectly, at least
         50% of the total voting power of the Company entitled to vote
         generally in the election of the Board; 


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    b.   the stockholders of the Company approve (i) a plan of complete
         liquidation of the Company, or (ii) an agreement providing for the
         merger or consolidation of the Company (A) in which the Company is not
         the continuing or surviving corporation (other than consolidation or
         merger with a wholly-owned subsidiary of the Company in which all
         Shares outstanding immediately prior to the effectiveness thereof are
         changed into or exchanged for the same consideration) or (B) pursuant
         to which the Shares are converted into cash, securities or other
         property, except a consolidation or merger of the Company in which the
         holders of the Shares immediately prior to the consolidation or merger
         have, directly or indirectly, at least a majority of the common stock
         of the continuing or surviving corporation immediately after such
         consolidation or merger or in which the Board immediately prior to the
         merger or consolidation would, immediately after the merger or
         consolidation, constitute a majority of the board of directors of the
         continuing or surviving corporation; or

    c.   the stockholders of the Company approve an agreement (or agreements)
         providing for the sale or other disposition (in one transaction or a
         series of transactions) of all or substantially all of the assets of
         the Company.

12. SECURITIES LAW REQUIREMENTS.

    No Shares shall be issued under the Plan unless and until:  (i) the Company
    and the Participant have taken all actions required to register the Shares
    under the Securities Act of 1933, as amended, or perfect an exemption from
    the registration requirements thereof; (ii) any applicable requirement of
    Nasdaq or any stock exchange on which the Common Stock is listed has been
    satisfied; and (iii) any other applicable provision of state or Federal law
    has been satisfied.  The Company shall be under no obligation to register
    the Shares under the Securities Act of 1933, as amended, or to effect
    compliance with the registration or qualification requirements of any state
    securities laws.

13. AMENDMENT AND TERMINATION.

    a.   MODIFICATIONS TO THE PLAN.

         The Board may, insofar as permitted by law, from time to time, with
         respect to any Shares at the time not subject to Options, suspend or
         terminate the Plan or revise or amend the Plan in any respect
         whatsoever.  However, unless the Board specifically otherwise
         provides, any revision or amendment that would cause the Plan to fail
         to comply with Rule 16b-3, Section 422 or 162(m) of the Code or any
         other requirement of applicable law or regulation if such amendment
         were not approved by the stockholders of the Company shall not be
         effective unless and until such approval is obtained.

    b.   RIGHTS OF PARTICIPANT.

         No amendment, suspension or termination of the Plan that would
         adversely affect the right of any Participant with respect to an
         Option previously granted under the Plan will be effective without the
         written consent of the affected Participant.


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14. MISCELLANEOUS.

    a.   STOCKHOLDERS' RIGHTS.

         No Participant and no beneficiary or other person claiming under or
         through such Participant shall acquire any rights as a stockholder of
         the Company by virtue of such Participant having been granted an
         Option under the Plan.  No Participant and no beneficiary or other
         person claiming under or through such Participant will have any right,
         title or interest in or to any Shares, allocated or reserved under the
         Plan or subject to any Option except as to Shares, if any, that have
         been issued or transferred to such Participant.  No adjustment shall
         be made for dividends or distributions or other rights for which the
         record date is prior to the date of exercise of an Option, except as
         may be provided in the Stock Option Agreement.

    b.   OTHER COMPENSATION ARRANGEMENTS.

         Nothing contained in the Plan shall prevent the Board from adopting
         other compensation arrangements, subject to stockholder approval if
         such approval is required.  Such other arrangements may be either
         generally applicable or applicable only in specific cases.

    c.   TREATMENT OF PROCEEDS.

         Proceeds realized from the exercise of Options under the Plan shall
         constitute general funds of the Company.

    d.   COSTS OF THE PLAN.

         The costs and expenses of administering the Plan shall be borne by the
         Company.

    e.   NO RIGHT TO CONTINUE EMPLOYMENT OR SERVICES.

         Nothing contained in the Plan or in any instrument executed pursuant
         to the Plan will confer upon any Participant any right to continue to
         render services to the Company, a Subsidiary or Affiliate; to continue
         as an Officer or Employee; or affect the right of the Company, a
         Subsidiary, the Board, the board of directors of a Subsidiary, the
         stockholders of the Company or a Subsidiary, as applicable, to
         terminate the office or employment, as the case may be, of any
         Participant at any time with or without Cause or with or without any
         other cause, reason or justification.  The term "Cause" as defined
         herein is included solely for the purposes of the Plan and is not, and
         shall not be deemed to be: (i) a restriction on the right of the
         Company or a Subsidiary, as the case may be, to terminate any Officer
         or Employee for any reason whatsoever; or (ii) a part of the
         employment relationship (whether oral or written, express or implied)
         of any such individual.

    f.   SEVERABILITY.

         The provisions of the Plan shall be deemed severable and the validity
         or unenforceability of any provision shall not affect the validity or
         enforceability of the other provisions hereof.


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    g.   BINDING EFFECT OF PLAN.

         The Plan shall inure to the benefit of the Company, its successors and
         assigns.

    h.   NO WAIVER OF BREACH.

         No waiver by any party hereto at any time of any breach by another
         party hereto of, or compliance with, any condition or provision of the
         Plan to be performed by such other party shall be deemed a waiver of
         the same, any similar or any dissimilar provisions of conditions at
         the same or at any prior or subsequent time.

    i.   GOVERNING LAW.

         The Plan and all actions taken thereunder shall be enforced, governed
         and construed by and interpreted under the laws of the State of
         Nebraska applicable to contracts made and to be performed wholly
         within such State without giving effect to the principles of conflict
         of laws thereof.

    j.   HEADINGS.

         The headings contained in the Plan are for reference purposes only and
         shall not affect in any way the meaning or interpretation of the Plan.

EXECUTION.

To record the adoption of the Plan to read as set forth herein, the Company has
caused the Plan to be signed by its President and attested by its Secretary on
September 19, 1996.


                                       ISCO, INC.,




                                       By:/s/Douglas M. Grant                  
                                          -------------------------------------
                                             Douglas M. Grant, President
ATTEST:




By:/s/Philip M. Wittig                     
   ----------------------------------------
      Philip M. Wittig, Assistant Secretary


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