NOVELTY - A high growth methanotrophic bacterial strain (I), which grows on a C1 carbon substrate e.g. methane and methanol, and comprises a functional Embden-Meyerhof carbon pathway comprising a gene (II) coding a pyrophosphate dependent phosphofrutokinase enzyme (III) or a 16s RNA comprising a sequence of 1429 nucleotides, given in the specification, is new.    USE - (I) produces glycogen comprising about 50 % dry weight of biomass. (I) is useful for the production of single cell protein, where (I) is contacted with a bacterial strain under anaerobic or aerobic conditions. (I) is also useful for the biotransformation of a nitrogen containing compound, e.g. ammonia, nitrate, nitrite or nitrogen. (I) is also useful for the production of a feed product comprising a protein, carbohydrates and a pigment. (I) is also useful in the production of a feed product (claimed). (I) is useful for reducing oxygen demand, for removing nitrates and nitrites in methane-containing environments such as landfills, waste water treatment systems or anywhere that methane, oxygen and nitrates are present. (I) is also useful as a denitrifying agent for the conversion of nitrate or nitrite to nitrous oxide with methane or methanol as a carbon source. (I) is also useful for the production of biomass including proteins, carbohydrates and a wide variety of pigments, particularly for isoprenoid pigments for the purpose of generating animal feeds. (I) is also useful for the production of terpenoid and carotenoid compounds, useful as pigments and as monomers in polymeric materials. (I) is also useful for producing exopolysaccharides at high levels. (I) is also useful as a food or feed product.    ADVANTAGE - (I) has a yield of greater than 1.0 g of cell mass/g of methane consumed. The carbon conversion efficiency of (I) is greater than 40 g/mol methane/g/mol biomass, preferably 70 g/mol methane/g/mol biomass (claimed). The possession of this pathway conveys an energetic advantage to the strain, making it particularly suitable as a production platform for the production of biomass from a C1 carbon source for more efficient production of commercially useful products. (I) produces upto 1.3 g/protein/dry weight/g methane and upto 0.45 g/protein/dry weight/g methanol. (I) is only capable of growth on methane or methanol and is incapable for proliferating in the human body, and thus is completely harmless and non-pathogenic. The strain has particularly high value in the production of food and feed materials as it is possible to manipulate the various concentrations of protein, carbohydrate and starch all within the same organism. (I) has no requirement for organic growth factors such as yeast extract or other costly fermentation additives. The strain requires only methane or methanol, inorganic minerals, oxygen and water for optimum growth, giving an advantage for large scale growth at low cost.    DETAILED DESCRIPTION - A new high growth methanotrophic bacterial strain (I), which grows on a C1 carbon substrate e.g. methane and methanol, comprises a functional Embden-Meyerhof carbon pathway comprising a gene (II) coding a pyrophosphate dependent phosphofrutokinase enzyme (III) or a 16s RNA comprising a sequence of 1429 nucleotides, given in the specification. (II) is selected from:    (a) an isolated nucleic acid molecule encoding a sequence (S1) comprising 437 amino acids, given in the specification;    (b) an isolated nucleic acid molecule that hybridizes with S1 under hybridization conditions (HC) comprising 0.1 X saline sodium citrate (SSC), 0.1 % sodium dodecyl sulfate (SDS), 65 degrees Centigrade and washed with 2 X SSC, 0.1 % SDS followed by 0.1 X SSC, 0.1 % SDS;    (c) an isolated nucleic acid molecule comprising a first nucleotide sequence encoding a polypeptide of at least 437 amino acids having at least 63 % identity based on the Smith-Waterman method of alignment when compared to a polypeptide having S1, and their complements.    An INDEPENDENT CLAIM is also included for identifying (I), comprising:    (a) growing a sample suspected of containing a high growth methanotrophic bacterial strain on a suitable growth medium in the presence of methane as a sole carbon source;    (b) identifying colonies that grow on the conditions; and    (c) analyzing the identified colonies for the activity of (III).