TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Promoter: The promoter of (I) or (II) comprises 1-465 bp of (S1). The promoter is present upstream to (I) or (II).Preferred Recombinant: The host is an absolute anaerobic bacterium, a facultative anaerobic bacterium or an aerobic bacterium or an eukaryotic cell.Preferred Method: In M1 the source material of hydrogen is chitin or starch. SPECIFIC SEQUENCES - (III) has a fully defined sequence of 582 aminoacids as given in the specification (claimed).    (IV) is Clostridium paraputrificum M strain (FERMP -16390) (claimed).    EXAMPLE - The amount of hydrogen gas produced by a recombinant and a control non-transformed organism was studied as follows. Clostridium paraputrificum M strain was cultured at 37 degrees C overnight in 100 mL of GS modified culture medium having glucose as carbon source. The microbial cells were recovered and centrifuged. Phenol-extraction and chloroform- extraction was carried out and chromosomal DNA was extracted. Partial degradation of the chromosomal DNA was performed by EcoRI and partially degraded chromosomal DNA of length 10000-20000 bp was ligated after purification and packed in phage particles. A gene library was constructed using this chromosomal DNA, by infecting E.coli DH5 alpha with the phage particle and bacteria were culture in LB agar-medium containing ampicillin. Transformed E.coli DH5 alpha were obtained which were ampicillin resistant. The hydrogenase gene was amplified by PCR using two primers based on the consensus sequences hydrogenase gene and the chromosomal DNA was used as the template. The 700 bp PCR products was ligated with pT7Blue (R) vector and transformed into E.coli. Ampicillin-resistant colonies were selected and plasmid XL1-Blue was extracted and separated by agarose gel electrophoresis. The base sequence of the plasmid was analyzed using DNA sequencer and it was found that the gene had homology to known Clostridium hydrogenase gene. The DNA fragment containing the hydrogenase gene was cloned. The hydrogenase gene was found to be novel and consisted of 1749 bp and encoded a protein having 582 amino aids. The regulatory sequence of the gene had 465 bp. The hydrogenase gene containing plasmid was built as follows. A shuttle vector pJIR751 was digested with XbaI and ligated to DNA fragment containing hydrogenase gene and regulatory gene, which was treated with alkali phosphatase, speI and xbaI. The ligated fragment was transformed into E.coli and the transformed organism was obtained. The transformed organism was cultured in GS modified culture medium containing N-acetyl-D-glucose amine obtained from shrimp shell or crab shell. The amount of hydrogen gas produced was measured. The recombinant produced 3.0-3.5 L of hydrogen per 1L culture medium and the control non-transformed organism produced 2.0 L of hydrogen per 1L of culture medium. The recombinant showed 1.5-1.8 times higher production of hydrogen than the non-transformed organism.