**EXHIBIT 10.15**

**REGISTRATION RIGHTS AGREEMENT**

ThisREGISTRATION RIGHTS AGREEMENT (this “*Agreement*”),dated as of March 31, 2006, is made by and between Earth Biofuels, Inc., a Delawarecorporation (the “*Company*”), andTom Groos (the “*Investor*”).

WHEREAS:

# **A.****                                   **In connection with the Convertible PromissoryNote in the principal amount of $450,000 of even date herewith by and between theCompany and the Investor (the “*Note*”),the Company has agreed to issue to the Investor shares of the Company’s commonstock (the “*Common Stock*”)upon the terms and subject to the limitations and conditions set forth in the Note;and

# **B.****                                   **To induce the Investor to execute the Note,the Company has agreed to provide certain registration rights under theSecurities Act of 1933, as amended, and the rules and regulations thereunder(collectively, the “*1933 Act*”),and applicable state securities laws;

**NOW, THEREFORE,** in consideration of the premises and themutual covenants contained herein and other good and valuable consideration,the receipt and sufficiency of which are hereby acknowledged, the Company andthe Investor hereby agree as follows:

## **1.****                                     ****DEFINITIONS.**

### Asused in this Agreement, the following terms shall have the following meanings:

#### **(i)****                                   **“*Investor*”means the Investor and any transferee or assignee who agrees to become bound bythe provisions of this Agreement in accordance with Section 9 hereof.

#### **(ii)****                               **“*register*,” “*registered*,” and “*registration*” refer to aregistration effected by preparing and filing a Registration Statement in compliancewith the 1933 Act and pursuant to Rule 415 under the 1933 Act or any successorrule providing for offering securities on a continuous basis (“*Rule 415*”), and the declaration ofeffectiveness of such Registration Statement by the United States Securitiesand Exchange Commission (the “*SEC*”).

#### **(iii)****                           **“*Registrable Securities*”means the all of the shares of Common Stock issued or issuable upon conversionpursuant to the Note.

#### **(iv)****                              **“*Registration Statement*”means a registration statement of the Company under the 1933 Act.

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## **2.****                                     ****REGISTRATION.**

### **a.****                                      ****Mandatory Registration**.  TheInvestor shall be entitled to make written request for registration of theRegistrable Securities, no later than 90 days following conversion of theNote.  Provided that the Investor hasmade a timely request therefore, the Company shall effect the registration ofthe Registrable Securities.  Within forty-five(45) days of receipt of written request from the Investor, the Company shall filewith the SEC a Registration Statement to effect the registration of theRegistrable Securities that the Company has been requested to register fordisposition as described in the request of the Investor.

### **b.****                                      ****Piggy-Back Registrations**. Subject to the last sentence of this Section 2(b), if at any time priorto the expiration of the Registration Period (as hereinafter defined) theCompany shall determine to file with the SEC a Registration Statement relatingto an offering for its own account or the account of others under the 1933 Actof any of its equity securities (other than on Form S-4 or Form S-8 relating toequity securities to be issued solely in connection with any acquisition of anyentity or business or equity securities issuable in connection with stockoption or other employee benefit plans), the Company shall send to the Investorwritten notice of such determination and, if within fifteen (15) days after theeffective date of such notice, the Investor shall so request in writing, theCompany shall include in such Registration Statement all or any part of theRegistrable Securities the Investor requests to be registered.  If an offering in connection with which the Investoris entitled to registration under this Section 2(b) is an underwrittenoffering, then the Investor shall, unless otherwise agreed by the Company,offer and sell such Registrable Securities in an underwritten offering usingthe same underwriter or underwriters and, subject to the provisions of thisAgreement, on the same terms and conditions as other shares of Common Stockincluded in such underwritten offering. Notwithstanding anything to the contrary set forth herein, theregistration rights of the Investor pursuant to this Section 2(b) shall only beavailable in the event the Company fails to timely file, obtain effectivenessor maintain effectiveness of any Registration Statement to be filed pursuant toSection 2(a) in accordance with the terms of this Agreement.

### **c.****                                      ****Eligibility for Form SB-2**.  TheCompany represents and warrants that it meets the requirements for the use ofSB-2 for registration of the sale by the Investor of the RegistrableSecurities.   The Company agrees to fileall reports required to be filed by the Company with the SEC in a timely mannerso as to remain eligible or become eligible, as the case may be, and thereafterto maintain its eligibility, for the use of Form SB-2.

## **3.****                                     ****OBLIGATIONS OF THE COMPANY.**

In connection with theregistration of the Registrable Securities, the Company shall have thefollowing obligations:

### **a.****                                      **The Company shall keep the RegistrationStatement effective pursuant to Rule 415 at all times until such date as is theearlier of (i) the date on which all of the Registrable Securities have beensold and (ii) the date on which the Registrable Securities (in the opinion ofcounsel to the Investor) may be immediately sold to the public withoutregistration or restriction (including, without limitation, as to volume by theholder thereof) under the 1933 Act (the “*Registration Period*”),which Registration Statement (including any amendments or

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### supplementsthereto and prospectuses contained therein) shall not contain any untruestatement of a material fact or omit to state a material fact required to bestated therein, or necessary to make the statements therein not misleading.

### **b.****                                      **The Company shall prepare and file with theSEC such amendments (including post-effective amendments) and supplements tothe Registration Statement and the prospectus used in connection with theRegistration Statement as may be necessary to keep the Registration Statementeffective at all times during the Registration Period, and, during such period,comply with the provisions of the 1933 Act with respect to the disposition ofall Registrable Securities of the Company covered by the Registration Statementuntil such time as all of such Registrable Securities have been disposed of inaccordance with the intended methods of disposition thereof as set forth in theRegistration Statement.

### **c.****                                      **The Company shall furnish to the Investor (i) promptly(but in no event more than two (2) business days) after the same is preparedand publicly distributed, filed with the SEC, or received by the Company, onecopy of each Registration Statement and any amendment thereto, each preliminaryprospectus and prospectus and each amendment or supplement thereto, and (ii) promptly(but in no event more than two (2) business days) after the RegistrationStatement is declared effective by the SEC, such number of copies of aprospectus, including a preliminary prospectus, and all amendments andsupplements thereto and such other documents as the Investor may reasonablyrequest in order to facilitate the disposition of the Registrable Securitiesowned by the Investor.  The Company willimmediately notify the Investor by facsimile of the effectiveness of each RegistrationStatement or any post-effective amendment. The Company will promptly (but in no event more than five (5) businessdays) respond to any and all comments received from the SEC (which commentsshall promptly be made available to the Investor upon request), with a viewtowards causing each Registration Statement or any amendment thereto to bedeclared effective by the SEC as soon as practicable, shall promptly file anacceleration request as soon as practicable (but in no event more than two (2)business days) following the resolution or clearance of all SEC comments or, ifapplicable, following notification by the SEC that any such RegistrationStatement or any amendment thereto will not be subject to review and shallpromptly file with the SEC a final prospectus as soon as practicable (but in noevent more than two (2) business days) following receipt by the Company fromthe SEC of an order declaring the Registration Statement effective.

### **d.****                                      **The Company shall use reasonable efforts to (i) registerand qualify the Registrable Securities covered by the Registration Statementunder such other securities or “blue sky” laws of such jurisdictions in theUnited States as the Investor reasonably requests, (ii) prepare and filein those jurisdictions such amendments (including post-effective amendments)and supplements to such registrations and qualifications as may be necessary tomaintain the effectiveness thereof during the Registration Period, (iii) takesuch other actions as may be necessary to maintain such registrations andqualifications in effect at all times during the Registration Period, and (iv) takeall other actions reasonably necessary or advisable to qualify the RegistrableSecurities for sale in such jurisdictions; provided, however,that the Company shall not be required in connection therewith or as acondition thereto to (a) qualify to do business in any jurisdiction whereit would not otherwise be required to qualify but for this Section 3(d), (b) subjectitself to general taxation in any such jurisdiction, (c) file a general

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### consentto service of process in any such jurisdiction, or (d) provide anyundertakings that cause the Company undue expense or burden.

### **e.****                                      **As promptly as practicable after becomingaware of such event, the Company shall notify the Investor of the happening ofany event, of which the Company has knowledge, as a result of which theprospectus included in any Registration Statement, as then in effect, includesan untrue statement of a material fact or omission to state a material factrequired to be stated therein or necessary to make the statements therein notmisleading, and use its best efforts promptly to prepare a supplement oramendment to any Registration Statement to correct such untrue statement oromission, and deliver such number of copies of such supplement or amendment to theInvestor as the Investor may reasonably request.

### **f.****                                        **The Company shall use its best efforts toprevent the issuance of any stop order or other suspension of effectiveness ofany Registration Statement, and, if such an order is issued, to obtain thewithdrawal of such order at the earliest possible moment and to notify the Investorof the issuance of such order and the resolution thereof.

### **g.****                                     **The Company shall take all other reasonableactions necessary to expedite and facilitate disposition by the Investor ofRegistrable Securities pursuant to a Registration Statement.

## **4.****                                     ****OBLIGATIONS OF THE INVESTOR.**

In connection with theregistration of the Registrable Securities, the Investor shall have the followingobligations:

### **a.****                                      **The Investor shall furnish to the Companysuch information regarding himself, the Registrable Securities held by him andthe intended method of disposition of the Registrable Securities held by him asshall be reasonably required to effect the registration of such RegistrableSecurities and shall execute such documents in connection with suchregistration as the Company may reasonably request.  At least three (3) business days prior to thefirst anticipated filing date of the Registration Statement, the Company shallnotify the Investor of the information the Company requires from the Investor.

### **b.****                                      **The Investor agrees to cooperate with theCompany as reasonably requested by the Company in connection with thepreparation and filing of the Registration Statement hereunder.

### **c.****                                      **The Investor agrees that, upon receipt of anynotice from the Company of the happening of any event of the kind described inSection 3(e) or 3(f), the Investor will immediately discontinue disposition ofRegistrable Securities pursuant to the Registration Statement covering suchRegistrable Securities until the Investor’s receipt of the copies of asupplemented or amended prospectus and, if so directed by the Company, the Investorshall deliver to the Company or destroy (and deliver to the Company acertificate of destruction) all copies in the Investor’ possession, of theprospectus covering such Registrable Securities current at the time of receiptof such notice.

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## **5.****                                     ****EXPENSES OF REGISTRATION.**

All reasonable expenses,other than underwriting discounts and commissions, incurred in connection withregistrations, filings or qualifications pursuant to Sections 2 and 3,including, without limitation, all registration, listing and qualificationfees, printers and accounting fees, and the fees and disbursements of counselfor the Company, shall be borne by the Company.

## **6.**                                      **INDEMNIFICATION.**

In the event any RegistrableSecurities are included in a Registration Statement under this Agreement:

### **a.****                                      **To the extent permitted by law, the Companywill indemnify, hold harmless and defend (i) the Investor who holds suchRegistrable Securities and (ii) the directors, officers, partners,employees, agents and each person who controls the Investor within the meaningof the 1933 Act or the Securities Exchange Act of 1934, as amended (the “*1934 Act*”), if any, (each, an “*Indemnified Person*”), against anyjoint or several losses, claims, damages, liabilities or expenses(collectively, together with actions, proceedings or inquiries by any regulatoryor self-regulatory organization, whether commenced or threatened, in respectthereof, “*Claims*”) to which any of themmay become subject insofar as such Claims arise out of or are based upon: (i)any untrue statement or alleged untrue statement of a material fact in aRegistration Statement or the omission or alleged omission to state therein amaterial fact required to be stated or necessary to make the statements thereinnot misleading; (ii) any untrue statement or alleged untrue statement of amaterial fact contained in any preliminary prospectus if used prior to theeffective date of such Registration Statement, or contained in the finalprospectus (as amended or supplemented, if the Company files any amendmentthereof or supplement thereto with the SEC) or the omission or alleged omissionto state therein any material fact necessary to make the statements madetherein, in light of the circumstances under which the statements therein weremade, not misleading; or (iii) any violation or alleged violation by theCompany of the 1933 Act, the 1934 Act, any other law, including, withoutlimitation, any state securities law, or any rule or regulation thereunderrelating to the offer or sale of the Registrable Securities (the matters in theforegoing clauses (i) through (iii) being, collectively, “*Violations*”).  The Company shall reimburse the IndemnifiedPerson, promptly as such expenses are incurred and are due and payable, for anyreasonable legal fees or other reasonable expenses incurred by the IndemnifiedPerson in connection with investigating or defending any such Claim.  Notwithstanding anything to the contrarycontained herein, the indemnification agreement contained in this Section 6(a):(i) shall not apply to a Claim arising out of or based upon a Violation whichoccurs in reliance upon and in conformity with information furnished in writingto the Company by any Indemnified Person expressly for use in connection withthe preparation of such Registration Statement or any such amendment thereof orsupplement thereto, if such prospectus was timely made available by the Companypursuant to Section 3(c) hereof; (ii) shall not apply to amounts paid insettlement of any Claim if such settlement is effected without the priorwritten consent of the Company, which consent shall not be unreasonablywithheld; and (iii) with respect to any preliminary prospectus, shall not inureto the benefit of any Indemnified Person if the untrue statement or omission ofmaterial fact contained in the preliminary prospectus was corrected on a timelybasis in the prospectus, as then amended or supplemented, such correctedprospectus was timely made available by the Company pursuant to Section 3(c)hereof, and the Indemnified Person was promptly advised in writing not to usethe incorrect prospectus prior to the use giving rise to a Violation and such 

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### IndemnifiedPerson, notwithstanding such advice, used it. Such indemnity shall remain in full force and effect regardless of anyinvestigation made by or on behalf of the Indemnified Person.

### **b.****                                      **In connection with any Registration Statementin which the Investor are participating, the Investor agrees to indemnify, holdharmless and defend, to the same extent and in the same manner set forth inSection 6(a), the Company, each of its directors, each of its officers whosigns the Registration Statement, each person, if any, who controls the Companywithin the meaning of the 1933 Act or the 1934 Act, any underwriter and anyother shareholder selling securities pursuant to the Registration Statement orany of its directors or officers or any person who controls such shareholder orunderwriter within the meaning of the 1933 Act or the 1934 Act (collectivelyand together with an Indemnified Person, an “*IndemnifiedParty*”), against any Claim to which any of them may becomesubject, under the 1933 Act, the 1934 Act or otherwise, insofar as such Claimarises out of or is based upon any Violation by such Investor, in each case tothe extent (and only to the extent) that such Violation occurs in reliance uponand in conformity with written information furnished to the Company by suchInvestor expressly for use in connection with such Registration Statement; and suchInvestor will reimburse any legal or other expenses (promptly as such expensesare incurred and are due and payable) reasonably incurred by them in connectionwith investigating or defending any such Claim; provided, however,that the indemnity agreement contained in this Section 6(b) shall not apply toamounts paid in settlement of any Claim if such settlement is effected withoutthe prior written consent of such Investor, which consent shall not beunreasonably withheld; provided, further, however, that suchInvestor shall be liable under this Agreement (including this Section 6(b) andSection 7) for only that amount as does not exceed the net proceeds to suchInvestor as a result of the sale of Registrable Securities pursuant to suchRegistration Statement.  Notwithstandinganything to the contrary contained herein, the indemnification agreementcontained in this Section 6(b) with respect to any preliminary prospectus shallnot inure to the benefit of any Indemnified Party if the untrue statement oromission of material fact contained in the preliminary prospectus was correctedon a timely basis in the prospectus, as then amended or supplemented.

### **c.****                                      **Promptly after receipt by an IndemnifiedPerson or Indemnified Party under this Section 6 of notice of the commencementof any action (including any governmental action), such Indemnified Person orIndemnified Party shall, if a Claim in respect thereof is to be made againstany indemnifying party under this Section 6, deliver to the indemnifying partya written notice of the commencement thereof, and the indemnifying party shallhave the right to participate in, and, to the extent the indemnifying party sodesires, jointly with any other indemnifying party similarly noticed, to assumecontrol of the defense thereof with counsel mutually satisfactory to theindemnifying party and the Indemnified Person or the Indemnified Party, as thecase may be; provided, however, that an Indemnified Person orIndemnified Party shall have the right to retain its own counsel with the feesand expenses to be paid by the indemnifying party, if, in the reasonable opinionof counsel retained by the indemnifying party, the representation by suchcounsel of the Indemnified Person or Indemnified Party and the indemnifyingparty would be inappropriate due to actual or potential differing interestsbetween such Indemnified Person or Indemnified Party and any other partyrepresented by such counsel in such proceeding. The indemnifying party shall pay for only one separate legal counsel forthe Indemnified Persons or the Indemnified Parties, as applicable, and suchlegal counsel shall be selected by the Investor if the Investor is entitled toindemnification 

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### hereunder,or the Company, if the Company is entitled to indemnification hereunder, asapplicable.  The failure to deliverwritten notice to the indemnifying party within a reasonable time of thecommencement of any such action shall not relieve such indemnifying party ofany liability to the Indemnified Person or Indemnified Party under this Section6, except to the extent that the indemnifying party is actually prejudiced inits ability to defend such action.  Theindemnification required by this Section 6 shall be made by periodic paymentsof the amount thereof during the course of the investigation or defense, assuch expense, loss, damage or liability is incurred and is due and payable.

## **7.****                                     ****CONTRIBUTION.**

To the extent anyindemnification by an indemnifying party is prohibited or limited by law, theindemnifying party agrees to make the maximum contribution with respect to anyamounts for which it would otherwise be liable under Section 6 to the fullestextent permitted by law; provided, however, that (i) nocontribution shall be made under circumstances where the maker would not havebeen liable for indemnification under the fault standards set forth in Section6, (ii) no seller of Registrable Securities guilty of fraudulentmisrepresentation (within the meaning of Section 11(f) of the 1933 Act) shallbe entitled to contribution from any seller of Registrable Securities who wasnot guilty of such fraudulent misrepresentation, and (iii)contribution(together with any indemnification or other obligations under this Agreement)by any seller of Registrable Securities shall be limited in amount to the netamount of proceeds received by such seller from the sale of such RegistrableSecurities.

## **8.****                                     ****REPORTS UNDER THE 1934 ACT.**

With a view to makingavailable to the Investor the benefits of Rule 144 promulgated under the 1933Act or any other similar rule or regulation of the SEC that may at any timepermit the Investor to sell securities of the Company to the public withoutregistration (“*Rule 144*”), the Companyagrees to:

### **a.****                                      **make and keep public information available,as those terms are understood and defined in Rule 144;

### **b.****                                      **file with the SEC in a timely manner allreports and other documents required of the Company under the 1933 Act and the1934 Act so long as the Company remains subject to such requirements and thefiling of such reports and other documents is required for the applicableprovisions of Rule 144; and

### **c.****                                      **furnish to the Investor so long as the Investorowns Registrable Securities, promptly upon request, (i) a writtenstatement by the Company that it has complied with the reporting requirementsof Rule 144, the 1933 Act and the 1934 Act, (ii) a copy of the most recentannual or quarterly report of the Company and such other reports and documentsso filed by the Company, and (iii) such other information as may bereasonably requested to permit the Investor to sell such securities pursuant toRule 144 without registration.

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## **9.****                                     ****ASSIGNMENT OF REGISTRATIONRIGHTS.**

The rights under thisAgreement shall be automatically assignable by the Investor to any transfereeof all or any portion of the Note if: (i) the Investor agrees in writingwith the transferee or assignee to assign such rights, and a copy of suchagreement is furnished to the Company within a reasonable time after suchassignment, (ii) the Company is, within a reasonable time after suchtransfer or assignment, furnished with written notice of the name and addressof such transferee or assignee, (iii) at or before the time the Companyreceives the written notice contemplated by clause (ii) of this sentence, thetransferee or assignee agrees in writing with the Company to be bound by all ofthe provisions contained herein, and (iv) such transferee shall be an “*accredited investor*” as that termdefined in Rule 501 of Regulation D promulgated under the 1933 Act.

## **10.****                              ****AMENDMENT OF REGISTRATIONRIGHTS.**

Provisions of this Agreementmay be amended and the observance thereof may be waived (either generally or ina particular instance and either retroactively or prospectively), only withwritten consent of the Company and the Investor.  Any amendment or waiver effected inaccordance with this Section 10 shall be binding upon the Investor and theCompany.

## **11.****                              ****MISCELLANEOUS.**

### **a.****                                      **A person or entity is deemed to be a holderof Registrable Securities whenever such person or entity owns of record suchRegistrable Securities.  If the Companyreceives conflicting instructions, notices or elections from two or morepersons or entities with respect to the same Registrable Securities, theCompany shall act upon the basis of instructions, notice or election receivedfrom the registered owner of such Registrable Securities.

### **b.****                                      **All notices and other communicationshereunder shall be in writing or by telecopy, and shall be deemed to have beenduly made when delivered in person or sent by telecopy, same day or overnightcourier, or 72 hours after having been deposited in the United Statesregistered or certified mail return receipt requested, postage prepaid, to aparty at the address set forth below (which may be changed in accordance withthese notice procedures):

| If to the Company:                  |
|-------------------------------------|
|                                |
| Earth Biofuels,  Inc.               |
| 3001 Knox  Street, Suite 403        |
| Dallas, TX 75205                    |
| Fax Number:  (214) 389-9805         |
| Attention: Chief  Executive Officer |
|                                |
|                                |
| With a copy to:                     |
|                                |
| Roger A. Crabb                      |
| Scheef &  Stone, LLP            |
| 5956 Sherry  Lane, Suite 1400       |
| Dallas, TX 75225                    |
| Fax number:  (214) 706-4242         |

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| If to the Investor:           |
|-------------------------------|
|                          |
| Tom Groos                     |
| 161 Ottawa St.  NW, Suite 502 |
| Grand Rapids,  Michigan 49503 |
| Fax number:  (616) 831-6454   |

 

### **c.****                                      **Failure of any party to exercise any right orremedy under this Agreement or otherwise, or delay by a party in exercisingsuch right or remedy, shall not operate as a waiver thereof.

### **d.****                                      ** This Agreement shall be governed by andconstrued in accordance with the laws of the State of Texas.  In the event of a dispute involving thisAgreement or any other instruments executed in connection herewith, the partiesirrevocably agree that exclusive venue for such dispute shall lie in any courtof competent jurisdiction in Dallas County, Texas, and the parties waive anyclaim that such forum is inappropriate or inconvenient.

### **e.****                                      **In the event that any provision of thisAgreement is invalid or unenforceable under any applicable statute or rule oflaw, then such provision shall be deemed inoperative to the extent that it mayconflict therewith and shall be deemed modified to conform with such statute orrule of law.  Any provision hereof whichmay prove invalid or unenforceable under any law shall not affect the validityor enforceability of any other provision hereof.

### **f.****                                        **This Agreement constitutes the entireagreement among the parties hereto with respect to the subject matterhereof.  There are no restrictions,promises, warranties or undertakings, other than those set forth or referred toherein and therein.  This Agreementsupersedes all prior agreements and understandings among the parties heretowith respect to the subject matter hereof.

### **g.****                                     **Subject to the requirements of Section 9hereof, this Agreement shall be binding upon and inure to the benefit of theparties and their successors and assigns.

### **h.****                                     **The headings in this Agreement are forconvenience of reference only and shall not form part of, or affect theinterpretation of, this Agreement.

### **i.****                                        **This Agreement may be executed in two or morecounterparts, each of which shall be deemed an original but all of which shallconstitute one and the same agreement and shall become effective whencounterparts have been signed by each party and delivered to the other parties.  This Agreement, once executed by a party, maybe delivered to the other parties hereto by facsimile transmission of a copy ofthis Agreement bearing the signature of the party so delivering this Agreement.

### **j.****                                        **Each party shall do and perform, or cause tobe done and performed, all such further acts and things, and shall execute anddeliver all such other agreements, certificates, instruments and documents, asthe other parties may reasonably request in order to carry out the intent andaccomplish the purposes of this Agreement and the consummation of thetransactions contemplated hereby.

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**IN WITNESSWHEREOF,** the Companyand the Investor have caused this Agreement to be duly executed as of the datefirst above written.
| EARTH BIOFUELS, INC.    | ** **                        | ** ** |
|-------------------------|-----------------------------------|------------|
| ** **              | ** **                        | ** ** |
| ** **              | ** **                        |
| **By:**                 | **/s/ DENNIS G. MCLAUGHLIN, III** | ** ** | ** ** |
| Name:                   | Dennis G. McLaughlin, III         |       |
| Title:                  | Chief Executive Officer           |       |
|                    |                              |       |
|                    |                              |       |
| **TOM GROOS**           |                              |
| ** **              |                              |
| ** **              |                              |
| /s/ TOM GROOS           |                              |       |
| Tom Groos, individually |                              |
|                         |                                   |            |  |  |  |

 

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