Exhibit 4 SECOND AMENDMENT TO INDENTURE, SECURITIES, WARRANT AGREEMENT AND WARRANT CERTIFICATES THIS SECOND AMENDMENT TO INDENTURE, SECURITIES, WARRANT AGREEMENT AND WARRANT CERTIFICATES (this "Second Amendment") is made as of and shall be effective for all purposes as of the 28th day of March, 2006, by and between Igene Biotechnology, Inc., a Maryland corporation (the "Company"), and American Stock Transfer & Trust Company, a New York corporation, its successors and assigns, as Trustee (the "Trustee") and as Warrant Agent (the "Warrant Agent"). RECITALS WHEREAS, pursuant to the terms of an Indenture dated as of March 31, 1998, as amended (the "Indenture") between the Company and the Trustee, the Company issued and sold $5,000,000 of its 8% notes due March 31, 2003 (the "Securities"); and WHEREAS, concurrently with the issue of the Securities, the Company issued, pursuant to a Warrant Agreement dated as of March 31, 1998 (the "Warrant Agreement"), 50,000,000 warrants to purchase shares of the Company's Common Stock for $.10 per share, as adjusted in accordance with the terms of the Warrant Agreement; and WHEREAS, on March 18, 2003, the Company and the Consenting Holders (as defined below) amended the Indenture and Securities to reflect the extension of the maturity date on the Securities to March 31, 2006; and WHEREAS, the Company and the Consenting Holders desire to further amend the Indenture and Securities as hereinafter provided to reflect the extension of the maturity date on the Securities from March 31, 2006 until March 31, 2009; and WHEREAS, in return for amending the Indenture and extending the maturity date on the Securities, the Consenting Holders and the Company desire to amend the terms of the Warrant Agreement and each of the Warrant Certificates (within the meaning of the Warrant Agreement) as hereinafter provided to reduce the Warrant Price (as defined in the Warrant Agreement) from $.075 to $.056; and WHEREAS, the terms contained in this Second Amendment are consented to by the holders of at least two-thirds principal amount of all Securities (collectively, the "Consenting Holders"); NOW, THEREFORE, in consideration of the foregoing recitals, and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties to this Second Agreement hereby agree as follows: 1. Incorporation of Recitals. _________________________ The foregoing recitals are incorporated in this Second Amendment and made a part hereof by this reference to the same extent as if set forth herein in full. All section references shall, unless otherwise expressly indicated, mean the corres- ponding section of the Indenture. 2. Definitions. ___________ All capitalized terms used but not defined herein shall have the meanings given such terms in the Indenture. 3. Amendment of the Indenture and Securities. _________________________________________ The Indenture and each of the Securities are hereby amended to replace "March 31, 2006" with "March 31, 2009" wherever such term may appear, thereby extending the maturity date of the Securities until March 31, 2009. 4. Amendment of Warrant Agreement. ______________________________ The Warrant Agreement and each Warrant Certificate is hereby amended to replace "$.075" with "$.056" wherever such term may appear. 5. Ratification of Indenture, Securities, Warrant Agreement and Warrant Certificates. _______________________________________________________ Except as set forth in this Second Amendment, all the terms and conditions contained in the Indenture, Securities, Warrant Agreement or Warrant Certificates, each, as amended, are hereby ratified and shall remain in full force and effect. In the event that any of the terms, conditions and provisions of this Second Amendment shall conflict with any of the terms, conditions and provisions of the Indenture, Securities, Warrant Agreement or Warrant Certificates, each, as amended, then, and in such event, the terms, conditions and provisions of this Second Amendment shall prevail and be controlling. Hereafter, all references to the Indenture, Securities, Warrant Agreement or any Warrant Certificate shall mean the Indenture, Securities, Warrant Agreement or such Warrant Certificate, respectively, as amended by this Second Amendment. 6. Effective Date of Second Amendment. __________________________________ The effective date of this Second Amendment shall be March 28, 2006. 7. Counterparts. ____________ This Second Amendment may be executed in any number of counterparts, each of which shall be deemed an original, and all of which, when taken together, shall be deemed to be a single instrument. 8. Applicable Law. ______________ This Second Amendment shall be governed by the laws of the State of New York, without regard to its conflicts of law rules. 9. Disclaimer. __________ In accordance with Section 7.04 of the Indenture, American Stock Transfer and Trust Company makes no representation or warranty as to the validity or adequacy of this Second Amendment and shall not be responsible for any of the recitals set forth herein. IN WITNESS WHEREOF, and intending to be legally bound, the Company, Trustee and Warrant Agent have caused this Second Amendment to be executed on their behalf by their duly authorized representatives as of the date set forth above. ATTEST: THE COMPANY: IGENE BIOTECHNOLOGY, INC. /s/ CHRISTINE L. FITCH By: /s/ STEPHEN F. HIU _________________________ _________________________ CHRISTINE L. FITCH Name: STEPHEN F. HIU Title: President ATTEST: THE TRUSTEE AND WARRANT AGENT: AMERICAN STOCK TRANSFER & TRUST COMPANY /s/ SUSAN SILBER By: /s/ HERBERT J. LEMMER _______________________ _______________________________ SUSAN SILBER Name: HERBERT J. LEMMER Title: Vice President CONSENT OF CONSENTING HOLDERS Each of the undersigned, collectively constituting holders of at least two-thirds in principal amount of all Securities, do hereby irrevocably consent, on behalf of all holders of Securities pursuant to and in accordance with the terms of the Indenture, to the amendment of the Securities, the Indenture, the Warrant Agreement and the Warrant Certificates, as set forth in this Second Amendment. Each of the persons signing below in their capacity as trustee on behalf of any trust represent that they currently serve as trustee under the trust(s) listed immediately above their names, and have the trust power and authority to sign below and to bind the trust(s) listed immediately above their names to this Consent of Consenting Holders in accordance with its terms. CONSENTING HOLDERS: WITNESS: /s/ PATRICIA SPERA /s/ THOMAS L. KEMPNER _______________________ _______________________________ PATRICIA SPERA THOMAS L. KEMPNER, record and beneficial holder of $32,395 principal amount of Securities WITNESS: /s/ MARY CLANCY /s/ SIDNEY R. KNAFEL _______________________ _______________________________ MARY CLANCY SIDNEY R. KNAFEL, record holder of $1,214,544 principal amount of Securities WITNESS: Trust U/W of Carl M. Loeb FBO Thomas L. Kempner, beneficial and record holder of $944,933 principal amount of Securities /s/ PATRICIA SPERA /s/ THOMAS L. KEMPNER _______________________ _______________________________ PATRICIA SPERA THOMAS L. KEMPNER Trustee /s/ PATRICIA SPERA /s/ WILLIAM PERLMUTH _______________________ _______________________________ PATRICIA SPERA WILLIAM PERLMUTH Trustee WITNESS: Alan H. Kempner III, beneficial and record holder of $942,773 principal amount of Securities /s/ PATRICIA SPERA /s/ ALAN H. KEMPNER III _______________________ _______________________________ PATRICIA SPERA ALAN H. KEMPNER III WITNESS: Trust U/A dated 9/13/1978 FBO Andrew G. Knafel, holder of $340,341.50 principal amount of Securities /s/ ANNE HUNTER /s/ ANDREW G. KNAFEL _______________________ _______________________________ ANNE HUNTER ANDREW G. KNAFEL Trustee WITNESS: Trust U/A dated 9/13/1978 FBO Douglas R. Knafel, holder of $340,341.50 principal amount of Securities /s/ ANNE HUNTER /s/ ANDREW G. KNAFEL _______________________ ______________________________ ANNE HUNTER ANDREW G. KNAFEL Trustee