Document:

<PAGE>

                                                                    EXHIBIT 10.8

                              DIVERSA CORPORATION

                         EMPLOYEE STOCK PURCHASE PLAN

            Adopted by the Board of Directors on December 13, 1999
               Approved by the Stockholders on February 7, 2000
         Adjusted for 1 for 2.8806 reverse stock split approved by the
                    Board of Directors on December 13, 1999
                       Effective Date ___________, 1999

1.   Purpose.

     (a) The purpose of this Employee Stock Purchase Plan (the "Plan") is to
provide a means by which employees of Diversa Corporation, a Delaware
corporation (the "Company"), and its Affiliates, as defined in subparagraph
1(b), which are designated as provided in subparagraph 2(b), may be given an
opportunity to purchase stock of the Company.

     (b) The word "Affiliate" as used in the Plan means any parent corporation
or subsidiary corporation of the Company, as those terms are defined in Sections
424(e) and (f), respectively, of the Internal Revenue Code of 1986, as amended
(the "Code").

     (c) The Company, by means of the Plan, seeks to retain the services of its
employees, to secure and retain the services of new employees, and to provide
incentives for such persons to exert maximum efforts for the success of the
Company.

     (d) The Company intends that the rights to purchase stock of the Company
granted under the Plan be considered options issued under an "employee stock
purchase plan" as that term is defined in Section 423(b) of the Code.

2.   Administration.

     (a) The Plan shall be administered by the Board of Directors (the "Board")
of the Company unless and until the Board delegates administration to a
Committee, as provided in subparagraph 2(c).  Whether or not the Board has
delegated administration, the Board shall have the final power to determine all
questions of policy and expediency that may arise in the administration of the
Plan.

     (b) The Board shall have the power, subject to, and within the limitations
of, the express provisions of the Plan:

         (i)  To determine when and how rights to purchase stock of the Company
shall be granted and the provisions of each offering of such rights (which need
not be identical).

         (ii) To designate from time to time which Affiliates of the Company
shall be eligible to participate in the Plan.

                                       1.
<PAGE>

          (iii) To construe and interpret the Plan and rights granted under
it, and to establish, amend and revoke rules and regulations for its
administration.  The Board, in the exercise of this power, may correct any
defect, omission or inconsistency in the Plan, in a manner and to the extent it
shall deem necessary or expedient to make the Plan fully effective.

          (iv)  To amend the Plan as provided in paragraph 13.

          (v)   Generally, to exercise such powers and to perform such acts as
the Board deems necessary or expedient to promote the best interests of the
Company and its Affiliates and to carry out the intent that the Plan be treated
as an "employee stock purchase plan" within the meaning of Section 423 of the
Code.

     (c)  The Board may delegate administration of the Plan to a Committee
composed of one (1) or more members of the Board (the "Committee").  If
administration is delegated to a Committee, the Committee shall have, in
connection with the administration of the Plan, the powers theretofore possessed
by the Board, subject, however, to such resolutions, not inconsistent with the
provisions of the Plan, as may be adopted from time to time by the Board.  The
Board may abolish the Committee at any time and revest in the Board the
administration of the Plan.

     (d)  Any interpretation of the Plan by the Board of any decision made by
it under the Plan shall be final and binding on all persons.

3.   Shares Subject to the Plan.

     (a)  Subject to the provisions of paragraph 12 relating to adjustments upon
changes in stock, the stock that may be sold pursuant to rights granted under
the Plan shall not exceed in the aggregate Four Hundred Sixteen Thousand Five
Hundred Seventy-Nine (416,579) shares (determined after the stock split approved
by the Board on December 13, 1999) of the Company's common stock (the "Common
Stock") plus an annual increase to be added on the day of each Annual
Stockholders Meeting beginning with the Annual Stockholders Meeting in 2000,
equal to the least of (i) three-fourths of one percent (.75%) of the Company's
outstanding shares on each such date (rounded to the nearest whole share and
calculated on a fully diluted basis, that is assuming the exercise of all
outstanding stock options and warrants to purchase common stock), (ii) Three
Hundred Forty-Seven Thousand One Hundred Forty-Nine (347,149) shares (determined
after the stock split approved by the Board on December 13, 1999) and (iii) an
amount determined by the Board. If any right granted under the Plan shall for
any reason terminate without having been exercised, the Common Stock not
purchased under such right shall again become available for the Plan.

     (b)  The stock subject to the Plan may be unissued shares or reacquired
shares, bought on the market or otherwise.

4.   Grant of Rights; Offering.

     (a)  The Board or the Committee may from time to time grant or provide for
the grant of rights to purchase Common Stock of the Company under the Plan to
eligible employees (an "Offering") on a date or dates (the "Offering Date(s)")
selected by the Board or the Committee.  Each Offering shall be in such form and
shall contain such terms and conditions as the Board or

                                       2.
<PAGE>

the Committee shall deem appropriate, which shall comply with the requirements
of Section 423(b)(5) of the Code that all employees granted rights to purchase
stock under the Plan shall have the same rights and privileges. The terms and
conditions of an Offering shall be incorporated by reference into the Plan and
treated as part of the Plan. The provisions of separate Offerings need not be
identical, but each Offering shall include (through incorporation of the
provisions of this Plan by reference in the document comprising the Offering or
otherwise) the period during which the Offering shall be effective, which period
shall not exceed twenty-seven (27) months beginning with the Offering Date, and
the substance of the provisions contained in paragraphs 5 through 8, inclusive.

     (b)  If an employee has more than one (1) right outstanding under the
Plan, unless he or she otherwise indicates in agreements or notices delivered
hereunder, a right with a lower exercise price (or an earlier-granted right if
two (2) rights have identical exercise prices), will be exercised to the fullest
possible extent before a right with a higher exercise price (or a later-granted
right if two (2) rights have identical exercise prices) will be exercised.

5.   Eligibility.

     (a)  Rights may be granted only to employees of the Company or, as the
Board or the Committee may designate as provided in subparagraph 2(b), to
employees of any Affiliate of the Company.  Except as provided in subparagraph
5(b), an employee of the Company or any Affiliate shall not be eligible to be
granted rights under the Plan unless, on the Offering Date, such employee has
been in the employ of the Company or any Affiliate for such continuous period
preceding such grant as the Board or the Committee may require, but in no event
shall the required period of continuous employment be greater than two (2)
years.  In addition, unless otherwise determined by the Board or the Committee
and set forth in the terms of the applicable Offering, no employee of the
Company or any Affiliate shall be eligible to be granted rights under the Plan
unless, on the Offering Date, such employee's customary employment with the
Company or such Affiliate is for at least twenty (20) hours per week and at
least five (5) months per calendar year.

     (b)  The Board or the Committee may provide that each person who, during
the course of an Offering, first becomes an eligible employee of the Company or
designated Affiliate will, on a date or dates specified in the Offering which
coincides with the day on which such person becomes an eligible employee or
occurs thereafter, receive a right under that Offering, which right shall
thereafter be deemed to be a part of that Offering.  Such right shall have the
same characteristics as any rights originally granted under that Offering, as
described herein, except that:

          (i)  the date on which such right is granted shall be the "Offering
Date" of such right for all purposes, including determination of the exercise
price of such right;

          (ii) the period of the Offering with respect to such right shall begin
on its Offering Date and end coincident with the end of such Offering; and

                                       3.
<PAGE>

          (iii) the Board or the Committee may provide that if such person
first becomes an eligible employee within a specified period of time before the
end of the Offering, he or she will not receive any right under that Offering.

     (c)  No employee shall be eligible for the grant of any rights under the
Plan if, immediately after any such rights are granted, such employee owns stock
possessing five percent (5%) or more of the total combined voting power or value
of all classes of stock of the Company or of any Affiliate.  For purposes of
this subparagraph 5(c), the rules of Section 424(d) of the Code shall apply in
determining the stock ownership of any employee, and stock which such employee
may purchase under all outstanding rights and options shall be treated as stock
owned by such employee.

     (d)  An eligible employee may be granted rights under the Plan only if such
rights, together with any other rights granted under "employee stock purchase
plans" of the Company and any Affiliates, as specified by Section 423(b)(8) of
the Code, do not permit such employee's rights to purchase stock of the Company
or any Affiliate to accrue at a rate which exceeds twenty five thousand dollars
($25,000) of fair market value of such stock (determined at the time such rights
are granted) for each calendar year in which such rights are outstanding at any
time.

     (e)  Officers of the Company and any designated Affiliate shall be eligible
to participate in Offerings under the Plan; provided, however, that the Board
may provide in an Offering that certain employees who are highly compensated
employees within the meaning of Section 423(b)(4)(D) of the Code shall not be
eligible to participate.

6.   Rights; Purchase Price.

     (a)  On each Offering Date, each eligible employee, pursuant to an Offering
made under the Plan, shall be granted the right to purchase up to the number of
shares of Common Stock of the Company purchasable with a percentage designated
by the Board or the Committee not exceeding fifteen percent (15%) of such
employee's Earnings (as defined in subparagraph 7(a)) during the period which
begins on the Offering Date (or such later date as the Board or the Committee
determines for a particular Offering) and ends on the date stated in the
Offering, which date shall be no later than the end of the Offering.  The Board
or the Committee shall establish one (1) or more dates during an Offering (the
"Purchase Date(s)") on which rights granted under the Plan shall be exercised
and purchases of Common Stock carried out in accordance with such Offering.

     (b)  In connection with each Offering made under the Plan, the Board or the
Committee may specify a maximum number of shares that may be purchased by any
employee as well as a maximum aggregate number of shares that may be purchased
by all eligible employees pursuant to such Offering.  In addition, in connection
with each Offering that contains more than one (1) Purchase Date, the Board or
the Committee may specify a maximum aggregate number of shares which may be
purchased by all eligible employees on any given Purchase Date under the
Offering.  If the aggregate purchase of shares upon exercise of rights granted
under the Offering would exceed any such maximum aggregate number, the Board or
the Committee shall make a pro rata allocation of the shares available in as
nearly a uniform manner as shall be practicable and as it shall deem to be
equitable.

                                       4.
<PAGE>

     (c)  The purchase price of stock acquired pursuant to rights granted under
the Plan shall be not less than the lesser of:

          (i)  an amount equal to eighty-five percent (85%) of the fair market
value of the stock on the Offering Date; or

          (ii) an amount equal to eighty-five percent (85%) of the fair market
value of the stock on the Purchase Date.

7.   Participation; Withdrawal; Termination.

     (a)  An eligible employee may become a participant in the Plan pursuant to
an Offering by delivering an enrollment agreement to the Company within the time
specified in the Offering, in such form as the Company provides.  Each such
agreement shall authorize payroll deductions of up to the maximum percentage
specified by the Board or the Committee of such employee's Earnings during the
Offering.  "Earnings" is defined as an employee's regular salary or wages
(including amounts thereof elected to be deferred by the employee, that would
otherwise have been paid, under any arrangement established by the Company that
is intended to comply with Section 125, Section 401(k), Section 402(e)(3),
Section 402(h) or section 403(b) of the Code, and also including any deferrals
under a non-qualified deferred compensation plan or arrangement established by
the Company), and also, if determined by the Board or the Committee and set
forth in the terms of the Offering, may include any or all of the following: (i)
overtime pay, (ii) commissions, (iii) bonuses, incentive pay, profit sharing and
other remuneration paid directly to the employee, and/or (iv) other items of
remuneration not specifically excluded pursuant to the Plan.  Earnings shall not
include the cost of employee benefits paid for by the Company or an Affiliate,
education or tuition reimbursements, imputed income arising under any group
insurance or benefit program, traveling expenses, business and moving expense
reimbursements, income received in connection with stock options, contributions
made by the Company or an Affiliate under any employee benefit plan, and similar
items of compensation, as determined by the Board or the Committee.
Notwithstanding the foregoing, the Board or Committee may modify the definition
of "Earnings" with respect to one or more Offerings as the Board or Committee
determines appropriate.  The payroll deductions made for each participant shall
be credited to an account for such participant under the Plan and shall be
deposited with the general funds of the Company.  A participant may reduce
(including to zero) or increase such payroll deductions, and an eligible
employee may begin such payroll deductions, after the beginning of any Offering
only as provided for in the Offering.  A participant may make additional
payments into his or her account only if specifically provided for in the
Offering and only if the participant has not had the maximum amount withheld
during the Offering.

     (b)  At any time during an Offering, a participant may terminate his or her
payroll deductions under the Plan and withdraw from the Offering by delivering
to the Company a notice of withdrawal in such form as the Company provides.
Such withdrawal may be elected at any time prior to the end of the Offering
except as provided by the Board or the Committee in the Offering.  Upon such
withdrawal from the Offering by a participant, the Company shall distribute to
such participant all of his or her accumulated payroll deductions (reduced to
the extent, if any, such deductions have been used to acquire stock for the
participant) under the

                                       5.
<PAGE>

Offering, without interest, and such participant's interest in that Offering
shall be automatically terminated. A participant's withdrawal from an Offering
will have no effect upon such participant's eligibility to participate in any
other Offerings under the Plan but such participant will be required to deliver
a new enrollment agreement in order to participate in subsequent Offerings under
the Plan.

     (c)  Rights granted pursuant to any Offering under the Plan shall terminate
immediately upon cessation of any participating employee's employment with the
Company and any designated Affiliate, for any reason, and the Company shall
distribute to such terminated employee all of his or her accumulated payroll
deductions (reduced to the extent, if any, such deductions have been used to
acquire stock for the terminated employee), under the Offering, without
interest.

     (d)  Rights granted under the Plan shall not be transferable by a
participant other than by will or the laws of descent and distribution, or by a
beneficiary designation as provided in paragraph 14, and during a participant's
lifetime, shall be exercisable only by such participant.

8.   Exercise.

     (a)  On each Purchase Date specified therefor in the relevant Offering,
each participant's accumulated payroll deductions and other additional payments
specifically provided for in the Offering (without any increase for interest)
will be applied to the purchase of whole shares of stock of the Company, up to
the maximum number of shares permitted pursuant to the terms of the Plan and the
applicable Offering, at the purchase price specified in the Offering. No
fractional shares shall be issued upon the exercise of rights granted under the
Plan. The amount, if any, of accumulated payroll deductions remaining in each
participant's account after the purchase of shares which is less than the amount
required to purchase one share of Common Stock on the final Purchase Date of an
Offering shall be held in each such participant's account for the purchase of
shares under the next Offering under the Plan, unless such participant withdraws
from such next Offering, as provided in subparagraph 7(b), or is no longer
eligible to be granted rights under the Plan, as provided in paragraph 5, in
which case such amount shall be distributed to the participant after such final
Purchase Date, without interest. The amount, if any, of accumulated payroll
deductions remaining in any participant's account after the purchase of shares
which is equal to the amount required to purchase one or more whole shares of
Common Stock on the final Purchase Date of an Offering shall be distributed in
full to the participant after such Purchase Date, without interest.

     (b)  No rights granted under the Plan may be exercised to any extent unless
the shares to be issued upon such exercise under the Plan (including rights
granted thereunder) are covered by an effective registration statement pursuant
to the Securities Act of 1933, as amended (the "Securities Act") and the Plan is
in material compliance with all applicable state, foreign and other securities
and other laws applicable to the Plan.  If on a Purchase Date in any Offering
hereunder the Plan is not so registered or in such compliance, no rights granted
under the Plan or any Offering shall be exercised on such Purchase Date, and the
Purchase Date shall be delayed until the Plan is subject to such an effective
registration statement and such compliance, except that the Purchase Date shall
not be delayed more than twelve (12) months and the Purchase Date shall in no
event be more than twenty-seven (27) months from the Offering Date.  If on the

                                       6.
<PAGE>

Purchase Date of any Offering hereunder, as delayed to the maximum extent
permissible, the Plan is not registered and in such compliance, no rights
granted under the Plan or any Offering shall be exercised and all payroll
deductions accumulated during the Offering (reduced to the extent, if any, such
deductions have been used to acquire stock) shall be distributed to the
participants, without interest.

9.   Covenants of the Company.

     (a)  During the terms of the rights granted under the Plan, the Company
shall keep available at all times the number of shares of Common Stock required
to satisfy such rights.

     (b)  The Company shall seek to obtain from each federal, state, foreign or
other regulatory commission or agency having jurisdiction over the Plan such
authority as may be required to issue and sell shares of stock upon exercise of
the rights granted under the Plan.  If, after reasonable efforts, the Company is
unable to obtain from any such regulatory commission or agency the authority
which counsel for the Company deems necessary for the lawful issuance and sale
of stock under the Plan, the Company shall be relieved from any liability for
failure to issue and sell stock upon exercise of such rights unless and until
such authority is obtained.

10.  Use of Proceeds from Stock.

     Proceeds from the sale of stock pursuant to rights granted under the Plan
shall constitute general funds of the Company.

11.  Rights as a Stockholder.

     A participant shall not be deemed to be the holder of, or to have any of
the rights of a holder with respect to, any shares subject to rights granted
under the Plan unless and until the participant's shareholdings acquired upon
exercise of rights under the Plan are recorded in the books of the Company (or
its transfer agent).

12.  Adjustments upon Changes in Stock.

     (a)  If any change is made in the stock subject to the Plan, or subject to
any rights granted under the Plan (through merger, consolidation,
reorganization, recapitalization, stock dividend, dividend in property other
than cash, stock split, liquidating dividend, combination of shares, exchange of
shares, change in corporate structure or other transaction not involving the
receipt of consideration by the Company), the Plan and outstanding rights will
be appropriately adjusted in the class(es) and maximum number of shares subject
to the Plan and the class(es) and number of shares and price per share of stock
subject to outstanding rights.  Such adjustments shall be made by the Board or
the Committee, the determination of which shall be final, binding and
conclusive.  (The conversion of any convertible securities of the Company shall
not be treated as a "transaction not involving the receipt of consideration by
the Company.")

     (b)  In the event of:  (1) a dissolution or liquidation of the Company; (2)
a sale of all or substantially all of the assets of the Company; (3) a merger or
consolidation in which the Company is not the surviving corporation; (4) a
reverse merger in which the Company is the surviving corporation but the shares
of the Company's Common Stock outstanding immediately

                                       7.
<PAGE>

preceding the merger are converted by virtue of the merger into other property,
whether in the form of securities, cash or otherwise; (5) the acquisition by any
person, entity or group within the meaning of Section 13(d) or 14(d) of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), or any
comparable successor provisions (excluding any employee benefit plan, or related
trust, sponsored or maintained by the Company or any Affiliate of the Company)
of the beneficial ownership (within the meaning of Rule 13d-3 promulgated under
the Exchange Act, or comparable successor rule) of securities of the Company
representing at least fifty percent (50%) of the combined voting power entitled
to vote in the election of directors; or (6) the individuals who, as of the date
of the adoption of this Plan, are members of the Board (the "Incumbent Board";
(if the election, or nomination for election by the Company's stockholders, of a
new director was approved by a vote of at least fifty percent (50%) of the
members of the Board then comprising the Incumbent Board, such new director
shall upon his or her election be considered a member of the Incumbent Board)
cease for any reason to constitute at least fifty percent (50%) of the Board;
then the Board in its sole discretion may take any action or arrange for the
taking of any action among the following: (i) any surviving or acquiring
corporation may assume outstanding rights or substitute similar rights for those
under the Plan, (ii) such rights may continue in full force and effect, or (iii)
all participants' accumulated payroll deductions may be used to purchase Common
Stock immediately prior to or within a reasonable period of time following the
transaction described above and the participants' rights under the ongoing
Offering terminated.

13.  Amendment of the Plan or Offerings.

     (a)  The Board at any time, and from time to time, may amend the Plan or
the terms of one or more Offerings. However, except as provided in paragraph 12
relating to adjustments upon changes in stock, no amendment shall be effective
unless approved by the stockholders of the Company within twelve (12) months
before or after the adoption of the amendment, where the amendment will:

          (i)   Increase the number of shares reserved for rights under the
Plan;

          (ii)  Modify the provisions as to eligibility for participation in the
Plan or an Offering (to the extent such modification requires stockholder
approval in order for the Plan to obtain employee stock purchase plan treatment
under Section 423 of the Code or to comply with the requirements of Rule 16b-3
promulgated under the Exchange Act, or any comparable successor rule ("Rule 16b-
3"); or

          (iii) Modify the Plan or an Offering in any other way if such
modification requires stockholder approval in order for the Plan to obtain
employee stock purchase plan treatment under Section 423 of the Code or to
comply with the requirements of Rule 16b-3.

It is expressly contemplated that the Board may amend the Plan or an Offering in
any respect the Board deems necessary or advisable to provide eligible employees
with the maximum benefits provided or to be provided under the provisions of the
Code and the regulations promulgated thereunder relating to employee stock
purchase plans and/or to bring the Plan and/or rights granted under an Offering
into compliance therewith.

                                       8.
<PAGE>

     (b)  The Board may, in its sole discretion, submit any amendment to the
Plan or an Offering for stockholder approval.

     (c)  Rights and obligations under any rights granted before amendment of
the Plan or Offering shall not be impaired by any amendment of the Plan, except
with the consent of the person to whom such rights were granted, or except as
necessary to comply with any laws or governmental regulations, or except as
necessary to ensure that the Plan and/or rights granted under an Offering comply
with the requirements of Section 423 of the Code.

14.  Designation of Beneficiary.

     (a)  A participant may file a written designation of a beneficiary who is
to receive any shares and cash, if applicable, from the participant's account
under the Plan in the event of such participant's death subsequent to the end of
an Offering but prior to delivery to the participant of such shares and cash. In
addition, a participant may file a written designation of a beneficiary who is
to receive any cash from the participant's account under the Plan in the event
of such participant's death during an Offering.

     (b)  Such designation of beneficiary may be changed by the participant at
any time by written notice in the form prescribed by the Company.  In the event
of the death of a participant and in the absence of a beneficiary validly
designated under the Plan who is living (or if an entity, is otherwise in
existence) at the time of such participant's death, the Company shall deliver
such shares and/or cash to the executor or administrator of the estate of the
participant, or if no such executor or administrator has been appointed (to the
knowledge of the Company), the Company, in its sole discretion, may deliver such
shares and/or cash to the spouse or to any one (1) or more dependents or
relatives of the participant, or if no spouse, dependent or relative is known to
the Company, then to such other person as the Company may determine.

15.  Termination or Suspension of the Plan.

     (a)  The Board in its discretion, may suspend or terminate the Plan at any
time.  The Plan shall automatically terminate if all the shares subject to the
Plan pursuant to subparagraph 3(a) are issued.  No rights may be granted under
the Plan while the Plan is suspended or after it is terminated.

     (b)  Rights and obligations under any rights granted while the Plan is in
effect shall not be impaired by suspension or termination of the Plan, except as
expressly provided in the Plan or with the consent of the person to whom such
rights were granted, or except as necessary to comply with any laws or
governmental regulation, or except as necessary to ensure that the Plan and/or
rights granted under an Offering comply with the requirements of Section 423 of
the Code.

16.  Effective Date of Plan.

     The Plan shall become effective on the same day on which the Company's
registration statement under the Securities Act with respect to the initial
public offering of shares of the Company's Common Stock becomes effective (the
"Effective Date"), but no rights granted under the Plan shall be exercised
unless and until the Plan had been approved by the stockholders

                                       9.
<PAGE>

of the Company within twelve (12) months before or after the date the Plan is
adopted by the Board or the Committee, which date may be prior to the Effective
Date.

17.  Choice of Law.

     All questions concerning the construction, validity and interpretation of
this Plan shall be governed by the law of the State of California, without
regard to such state's conflict of laws rules.

                                      10.NOTHING CORP

            INCORPORATED UNDER THE LAWS OF THIS STATE OF NEVADA
        25,000,000 SHARES COMMON STOCK AUTHORIZED, $.001 PAR VALUE
THIS
CERTIFIES
THAT                                                   SEE REVERSE FOR
                                                       CERTAIN DEFINITIONS

IS THE OWNER OF

          FULLY PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK OF
                                NOTHING CORP

     transferable on the books of the corporation in person or by duly
 authorized attorney upon surrender of this certificate properly endorsed.
This certificate and the shares represented hereby are subject to the laws
of this State of Nevada, and to the Certificate of Incorporation and Bylaws
  of the Corporation, as now hereafter amended.  This certificate is not
 valid unless countersigned by the Transfer Agent.  WITNESS the facsimile
seal of the Corporation and the signature of its duly authorized officers.

DATE

                                NOTHING CORP
                              Corporate Seal
                                  Nevada
                                                  SECRETARY

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00001-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00001-of-00352.parquet"}]]