Hydrogen production

Abstract

The enzyme, iron hydrogenase (HydA), has industrial applications for the production of hydrogen, specifically, for catalyzing the reversible reduction of protons to molecular hydrogen. The present invention relates to the isolation of a nucleic acid sequence from the algae Scenedesmus obliquus, Chlamydomonas reinhardtii and Chlorella fusca that encodes iron hydrogenase. The invention further discloses the genomic nucleic acid, c-DNA and the protein sequences for HydA. The genes and gene products may be used in a photosynthetic process for hydrogen production which includes growing a microorganism containing the gene coding for HydA in a culture medium under illuminated conditions sufficient to accumulate an endogenous substrate; depleting a nutrient selected from the group consisting of sulfur, iron, and manganese from the medium; then allowing the culture to become anaerobic by consumption of an endogenous or exogenous substrate in the light.

1 . An isolated nucleic acid sequence comprising SEQ. ID. NO. 1.  
     
     
         2 . A hydrogenase having an amino acid sequence comprising SEQ. ID. No. 4:  
     
     
         3 . An isolated nucleic acid sequence comprising SEQ. ID. NO. 7.  
     
     
         4 . (canceled)  
     
     
         5 . A hydrogenase having an amino acid sequence comprising SEQ. ID. NO. 5.  
     
     
         6 . (canceled)  
     
     
         7 . An isolated nucleic acid sequence comprising SEQ. ID. NO. 3.  
     
     
         8 . A hydrogenase having an amino acid sequence comprising SEQ. ID. NO. 6.  
     
     
         9 . An isolated nucleic acid sequence comprising SEQ. ID. NO. 9.  
     
     
         10 . A cell comprising an isolated nucleic acid sequence encoding a protein comprising SEQ. ID. NO. 4.  
     
     
         11 . (canceled)  
     
     
         12 . A cell comprising an isolated nucleic acid sequence encoding a protein comprising SEQ. ID. NO. 6.  
     
     
         13 . A photosynthetic process for hydrogen production comprising the steps of: (a) growing a microorganism containing a gene coding for HydA having a nucleic acid sequence set forth in SEQ. ID. NO. 2 in a culture medium containing nutrients under illuminated conditions sufficient to accumulate an endogenous substrate; then (b) depleting a nutrient in the culture medium selected from the group consisting of sulfur, iron, and manganese; then (c) allowing the culture to become anaerobic by consumption of an endogenous or exogenous substrate in the light.  
     
     
         14 . The photosynthetic process for hydrogen production in accordance with  claim 13  wherein said nucleic acid sequence comprises SEQ. ID. NO. 2.  
     
     
         15 . The photosynthetic process for hydrogen production in accordance with  claim 13  wherein said nucleic acid sequence comprises SEQ. ID. NO. 3.  
     
     
         16 . A photosynthetic process for hydrogen production comprising the steps of: (a) growing a microorganism producing a Fe-Hydrogenase enzyme comprising an amino acid sequence sequence set forth in SEQ. ID. NO. 4 in a culture medium containing nutrients under illuminated conditions sufficient to accumulate an endogenous substrate; then (b) depleting a nutrient in the culture medium selected from the group consisting of sulfur, iron, and manganese; then (c) allowing the culture to become anaerobic by consumption of an endogenous or exogenous substrate in the light.  
     
     
         17 . The photosynthetic process of  claim 16  wherein said amino acid sequence of said Fe-Hydrogenase enzyme comprises an amino acid sequence as set forth in SEQ. ID. NO 5.  
     
     
         18 . The photosynthetic process of  claim 16  wherein said amino acid sequence of said Fe-Hydrogenase enzyme comprises an amino acid sequence as set forth in SEQ. ID. NO 6.  
     
     
         19 . An isolated amino acid sequence selected from the group consisting of SEQ ID NO. 4, SEQ ID NO. 5, or SEQ ID NO. 6.  
     
     
         20 . An isolated amino acid sequence with 75% or more sequence homology to a polypeptide selected from the group consisting of SEQ ID NO. 4, SEQ ID NO. 5, or SEQ ID NO. 6.