JP2730671B

PROBLEM TO BE SOLVED: To obtain the subject new microorganism which is a cyanobacterium Synechococcus sp. MA strain having the ability to produce poly-β-hydroxybutyric acid and useful for producing the biodegradable resin poly-/β-hydroxybutyric acid, recycling, etc., of gaseous carbon dioxide. SOLUTION: This cyanobacterium is a new cyanobacterium Synechococcus sp. MA strain (FERM P-15099) having the ability to produce poly-β- hydroxybutyric acid and useful for producing the poly-β-hydroxybutyric acid expected as a thermoplastic resin degradable by microorganisms for utilization in many directions such as medicines, agrochemicals, medical materials and industrial materials and recycling, etc., of gaseous carbon dioxide. The cyanobacterium is obtained by culturing cyanobacterium granules from hot springs in various places in Japan in a culture medium at 50 deg.C under irradiation with light, separating the propagated cyanobacterium into single bacterium according to a plate smearing method, culturing the bacterium in a culture medium deficient in a nitrogen source and selecting the cyanobacterium capable of producing a large amount of the poly-β-hydroxybutyric acid.