Allegro
                Biodiesel Corporation

              6033
                West Century Blvd., Suite 1090

              Los
                Angeles, California 90045

              Tel:
                (310) 670-2093

              Fax:
                (310) 670-4107

              www.allegrobiodiesel.com 

            


    

    
      
        
          

        

      

       

      June
        13,
        2008

       

      Via
        Federal Express

       

      Attention:
        Ronda Carson

      JPMorgan
        Chase Bank, N.A.

      Escrow
        Services

      333
        South
        Grand Avenue, 36th
        Floor

      Los
        Angeles, CA 90065

       

      
        	 	
                Re:

              	
                Joint
                  Escrow Instructions re Escrow
                  Agreement (“Escrow Agreement”) by and among Diametrics Medical, Inc., the
                  Members and JPMorgan Chase Bank, N.A. dated as of September 20,
                  2006 

              


      

       

      Ladies
        and Gentlemen:

       

      Allegro
        Biodiesel Corporation (fka Diametrics Medical, Inc., “Allegro”) has submitted to
        you various demands for release from the Escrow Deposit under the Escrow
        Agreement. The parties to the Escrow Agreement have not resolved any of such
        claims other than Allegro’s demand dated February 22, 2008, for the release of
        $47,448.49 relating to certain taxes. Joint escrow instructions for the release
        of such amount were delivered to you on or about May 16, 2008. 

       

      Notwithstanding
        that our remaining claims continue to be outstanding, the parties to the
        Escrow
        Agreement have agreed to release a portion of the Cash Escrow Deposit and
        a
        portion of the Stock Escrow Deposit as set forth below.

       

      Accordingly,
        you are hereby instructed to release (i) to Allegro from the Cash Escrow
        Deposit
        the sum of $151,628.08
        and from
        the Stock Escrow Deposit, 124,961
        shares
        of Allegro common stock and (ii) to the Members from the Cash Escrow Deposit
        the
        aggregate sum of $201,129.30
        and from
        the Stock Escrow Deposit an aggregate of 126,250
        shares
        of Allegro common stock. It is requested that these funds and shares be released
        as promptly as possible. 

       

      
        	 	
                Funds
                  released to Allegro shall be paid by wire transfer to the following
                  account:

                 

                Bank
                  of America

                4754
                  Admiralty Way

                Marina
                  Del Rey, CA 90292

                ABA
                  No. 026009593

                 

                Account
                  Number 09145-41651

                 

                Shares
                  of Allegro common stock released to Allegro shall be delivered
                  to the
                  following address:

              


      

       

      
        
          
          

        

        
          
          

          
            

          

        

        
          
          

        

      

       

      
        	 	
                Allegro
                  Biodiesel Corporation

                6033
                  West Century Blvd., Suite 1090

                Los
                  Angeles, CA 90045

                Attention:
                  W. Bruce Comer III

                Telephone
                  No.: (310) 670-2721

              


      

       

      
        Funds
          released to the Members shall be paid by wire transfer to Troy Villa at
          Breazeale, Sachse & Wilson LLP, using the following
          information:

      

       

      
        	 	
                Regions
                  Bank

                8440
                  Jefferson Hwy. 

                Baton
                  Rouge, LA 70809

                ABA
                  No. 062005690

                Account
                  Number 1450901416

              
	 	
              


      

       

      
        
          
          

        

        
          
          

          
            

          

        

        
          
          

        

      

       

       

       

      
        		
                Allegro
                  Biodiesel Corporation

                6033
                  West Century Blvd., Suite 1090

                Los
                  Angeles, California 90045

                Tel:
                  (310) 670-2093

                Fax:
                  (310) 670-4107

                www.allegrobiodiesel.com 

              


      

       

      
        
          

        

      

       

      
        	 	
                Shares
                  of Allegro common stock released to the Members shall be delivered
                  to the
                  following address:

              
	 	 
	 	
                Breazeale,
                  Sachse & Wilson, L.L.P.

                23rd
                  Floor, One American Place

                301
                  Main Street

                Baton
                  Rouge, LA 70821-3197

                Attn:
                  B. Troy Villa

                Telephone
                  No.: (225) 387-4000

              
	 	 
	 	
                Capitalized
                  terms used herein without definition have the meaning ascribed
                  thereto
                  under the Escrow Agreement.

              


      

       

       

      
        
          
          

        

        
          
          

          
            

          

        

        
          
          

        

      

       

      
        		
                Allegro
                  Biodiesel Corporation

                6033
                  West Century Blvd., Suite 1090

                Los
                  Angeles, California 90045

                Tel:
                  (310) 670-2093

                Fax:
                  (310) 670-4107

                www.allegrobiodiesel.com 

              


      

       

      
        
 

       

      
        	 	Please call Stephen Blevit of Sidley
                Austin
                LLP at 213-896-6029 with any questions regarding these joint escrow
                instructions.
	 	 
	 	Very truly yours,
	 	 
	ALLEGRO BIODIESEL
                CORPORATION


      

       

       

      
        	
                 

                 

                By:     
                   /s/
                  W. Bruce Comer,
                  III                                    

                Name:
                  W. Bruce Comer, III

                Title:  
                  Chief Executive Officer

              	
                 

                 

                /s/  Darrell
                  Dubroc                                 
                      

                DARRELL
                  DUBROC,
                  

                as
                  Member Representative