PETROALGAE INC. GUARANTY

Exhibit 10.8

PETROALGAE INC. GUARANTY

FOR VALUE RECEIVED, and in consideration of note purchases from, loans made or to be made or credit otherwise extended or to be extended by PetroTech Holdings, Corp. (“PetroTech”) to or for the account of PA LLC (f/k/a PetroAlgae, LLC), a Delaware limited liability company (the “ Company ”), from time to time and at any time and for other good and valuable consideration and to induce PetroTech, in its discretion, to purchase such notes, make such loans or other extensions of credit and to make or grant such renewals, extensions, releases of collateral or relinquishments of legal rights as the Creditor Parties (as defined below) may deem advisable, PetroAlgae Inc. (“ Guarantor ” or “ the undersigned ”) unconditionally guaranties to the Creditor Parties, their successors, endorsees and assigns the prompt payment when due (whether by acceleration or otherwise) of all present and future obligations and liabilities of any and all kinds of the Company to the Creditor Parties and of all instruments of any nature evidencing or relating to any such obligations and liabilities upon which the Company or one or more parties and the Company is or may become liable to the Creditor Parties, whether incurred by the Company as maker, endorser, drawer, acceptor, guarantor, accommodation party or otherwise, and whether due or to become due, secured or unsecured, absolute or contingent, joint or several, and however or whenever acquired by the Creditor Parties, whether arising under, out of, or in connection with that certain (i) Second Amended and Restated Secured Term Note dated as of the date hereof, issued by the Company to PetroTech (as further amended, restated, modified and/or supplemented from time to time, the “ PetroTech Term Note ”) which amends and restates and combines that certain (a) Amended and Restated Demand Note issued as of August 25, 2008 (and dated August 21, 2008) by the Company to PetroTech which further amended and restated that Demand Note dates August 21, 2008 made by the Company in favor of PetroTech (as amended, restated, modified and/or supplemented from time to time) (b) Demand Note dated as of September 3, 2008 issued by Company to PetroTech (as amended, restated, modified and/or supplemented from time to time), (c) Demand Note dated as of September 18, 2008 issued by the Company to PetroTech (as amended, restated, modified and/or supplemented from time to time), (d) Demand Note dated as of September 25, 2008 issued by the Company to PetroTech (as amended, restated, modified and/or supplemented from time to time), (ii) Amended and Restated Secured Convertible Note dated as of the date hereof issued by the Company to PetroTech (as further amended, restated, modified and/or supplemented from time to time, the “ PetroTech Convertible Note ” and together with the PetroTech Term Note, the “ PetroTech Notes ”) which amends and restates and combines that certain (a) Convertible Demand Note dated as of April 24, 2009 issued by the Company to PetroTech (as amended, restated, modified and/or supplemented from time to time) and (b) Secured Convertible Demand Note dated as of May 11, 2009 issued by the Company to PetroTech (as amended, restated, modified and/or supplemented from time to time), (iii) that certain Promissory Note dated June 12, 2008 and effective as of September 22, 2006 issued by Company in favor of XL Techgroup, Inc., a Delaware corporation (“ XLT ”) and assigned in full by XLT to PetroTech (as amended, restated, modified and/or supplemented from time to time, the “ Promissory Note ”) (iv) that certain Amended and Restated Master Security Agreement dated as of the date hereof by the Company in favor of Agent (as defined below) (as further amended, restated, modified and/or supplemented from time to time, the “ PetroTech Master Security Agreement ”) which amends

and restates that certain Master Security Agreement dated as of August 21, 2008 by the Company in favor of the Agent on behalf of PetroTech (as amended, restated, modified and/or supplemented from time to time) and together with the PetroTech Notes, the Promissory Note and all other guarantees, security agreements, other agreements, instruments and documents executed and/or delivered in connection therewith, collectively and as the same may be amended or otherwise modified from time to time, the “ Documents ”) between Company and LV Administrative Services, Inc., as administrative and collateral agent to the PetroTech (the “ Agent ” and together with PetroTech and its assigns, the “ Creditor Parties ”; and each a “ Creditor Party ”) and any documents, instruments or agreements relating to or executed in connection with the Documents or any documents, instruments or agreements referred to therein or otherwise, or any other indebtedness, obligations or liabilities of the Company to the Creditor Parties, whether now existing or hereafter arising, direct or indirect, liquidated or unliquidated, absolute or contingent, due or not due and whether under, pursuant to or evidenced by a note, agreement, guaranty, instrument or otherwise (all of which are herein collectively referred to as the “ Obligations ”), and irrespective of the genuineness, validity, regularity or enforceability of such Obligations, or of any instrument evidencing any of the Obligations or of any collateral therefor or of the existence or extent of such collateral, and irrespective of the allowability, allowance or disallowance of any or all of the Obligations in any case commenced by or against the Company under Title 11, United States Code, including, without limitation, obligations or indebtedness of the Company for post-petition interest, fees, costs and charges that would have accrued or been added to the Obligations but for the commencement of such case. Terms not otherwise defined herein shall have the meaning assigned such terms in the Documents, as applicable. In furtherance of the foregoing, the undersigned hereby agrees as follows:

1. No Impairment . The Creditor Parties may at any time and from time to time, either before or after the maturity thereof, without notice to or further consent of the undersigned, extend the time of payment of, exchange or surrender any collateral for, renew or extend any of the Obligations or increase or decrease the interest rate thereon, or any other agreement with the Company or with any other party to or person liable on any of the Obligations, or interested therein, for the extension, renewal, payment, compromise, discharge or release thereof, in whole or in part, or for any modification of the terms thereof or of any agreement between any Creditor Party and the Company or any such other party or person, or make any election of rights the Creditor Parties may deem desirable under the United States Bankruptcy Code, as amended, or any other federal or state bankruptcy, reorganization, moratorium or insolvency law relating to or affecting the enforcement of creditors’ rights generally (any of the foregoing, an “ Insolvency Law ”) without in any way impairing or affecting this Guaranty. This Guaranty shall be effective regardless of the subsequent incorporation, merger or consolidation of the Company, or any change in the composition, nature, personnel or location of the Company and shall extend to any successor entity to the Company, including a debtor in possession or the like under any Insolvency Law.

2. Guaranty Absolute . Subject to Section 5(c) hereof, each of the undersigned guarantees that the Obligations will be paid strictly in accordance with the terms of the Documents and/or any other document, instrument or agreement creating or evidencing the Obligations, regardless of any law, regulation or order now or hereafter in effect in any jurisdiction affecting any of such terms or the rights of the Company with respect thereto. Guarantor hereby knowingly accepts the full range of risk encompassed within a contract of

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“continuing guaranty” which risk includes the possibility that the Company will contract additional indebtedness, obligations and liabilities for which Guarantor may be liable hereunder after the Company’s financial condition or ability to pay its lawful debts when they fall due has deteriorated, whether or not the Company has properly authorized incurring such additional indebtedness, obligations and liabilities. The undersigned acknowledge that (i) no oral representations, including any representations to extend credit or provide other financial accommodations to the Company, have been made by any Creditor Party to induce the undersigned to enter into this Guaranty and (ii) any extension of credit to the Company shall be governed solely by the provisions of the Documents. The liability of the undersigned under this Guaranty shall be absolute and unconditional, in accordance with its terms, and shall remain in full force and effect without regard to, and shall not be released, suspended, discharged, terminated or otherwise affected by, any circumstance or occurrence whatsoever, including, without limitation: (a) any waiver, indulgence, renewal, extension, amendment or modification of or addition, consent or supplement to or deletion from or any other action or inaction under or in respect of the Documents or any other instruments or agreements relating to the Obligations or any assignment or transfer of any thereof, (b) any lack of validity or enforceability of any Document or other documents, instruments or agreements relating to the Obligations or any assignment or transfer of any thereof, (c) any furnishing of any additional security to the Creditor Parties or their assignees or any acceptance thereof or any release of any security by the Creditor Parties or their assignees, (d) any limitation on any party’s liability or obligation under the Documents or any other documents, instruments or agreements relating to the Obligations or any assignment or transfer of any thereof or any invalidity or unenforceability, in whole or in part, of any such document, instrument or agreement or any term thereof, (e) any bankruptcy, insolvency, reorganization, composition, adjustment, dissolution, liquidation or other like proceeding relating to the Company, or any action taken with respect to this Guaranty by any trustee or receiver, or by any court, in any such proceeding, whether or not the undersigned shall have notice or knowledge of any of the foregoing, (f) any exchange, release or nonperfection of any collateral, or any release, or amendment or waiver of or consent to departure from any guaranty or security, for all or any of the Obligations or (g) any other circumstance which might otherwise constitute a defense available to, or a discharge of, the undersigned. Any amounts due from the undersigned to the Creditor Parties shall bear interest until such amounts are paid in full at the highest rate then applicable to the Obligations. Obligations include post-petition interest whether or not allowed or allowable.

3. Waivers .

(a) This Guaranty is a guaranty of payment and not of collection. The Creditor Parties shall be under no obligation to institute suit, exercise rights or remedies or take any other action against the Company or any other person or entity liable with respect to any of the Obligations or resort to any collateral security held by it to secure any of the Obligations as a condition precedent to the undersigned being obligated to perform as agreed herein and the Guarantor hereby waives any and all rights which it may have by statute or otherwise which would require the Creditor Parties to do any of the foregoing. The Guarantor further consents and agrees that the Creditor Parties shall be under no obligation to marshal any assets in favor of Guarantor, or against or in payment of any or all of the Obligations. The undersigned hereby waives all suretyship defenses and any rights to interpose any defense, counterclaim or offset of any nature and

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description which the undersigned may have or which may exist between and among any Creditor Party, the Company and/or the undersigned with respect to the undersigned’s obligations under this Guaranty, or which the Company may assert on the underlying debt, including but not limited to failure of consideration, breach of warranty, fraud, payment (other than cash payment in full of the Obligations), statute of frauds, bankruptcy, infancy, statute of limitations, accord and satisfaction, and usury.

(b) The undersigned further waives (i) notice of the acceptance of this Guaranty, of the making of any such loans or extensions of credit, and of all notices and demands of any kind to which the undersigned may be entitled, including, without limitation, notice of adverse change in the Company’s financial condition or of any other fact which might materially increase the risk of the undersigned and (ii) presentment to or demand of payment from anyone whomsoever liable