NOVELTY - A microorganism which can be grown in a culture medium containing caffeine as only source of organic substance nutrition, is new.    USE - For manufacturing organic substance materials such as fertilizer, soil substitute and soil improvement material, from caffeine containing materials such as residue of coffee and/or tea from domestic foodstuff works (claimed) or restaurants.    ADVANTAGE - The caffeine which inhibits the growth of crops, can be effectively decomposed in a short time. The microorganism especially Micrococcus sp. SAM2240 (FERM P-17511) strain, can be isolated from the coffee and/or tea extract residue efficiently. The residue of coffee and/or tea extract can be converted into organic substance such as fertilizer using the microorganism within a short period of time. 1 kg of mixture of microorganism (10 to the power of 8 cells/g) isolated from pig feces was dispersed in a culture medium containing caffeine (0.1 g), ammonium chloride (0.2 g), calcium chloride (0.1 g), potassium dihydrogen phosphate (0.1 g), hydrated magnesium sulfate (0.02), ferrous sulfate (0.01), cobalt chloride (10 microM) yeast extract (0.02 g) and water (100 ml). The culture solution was mixed with 5 kg of coffee extract residue and the pH was adjusted to neutral by sodium carbonate. The solution was placed in a wooden box and allow to ferment for 7 days. The culture solution was incubated in flat plate culture medium and 105 strains were isolated. The strains were cultivated for 36 hours at 30 degrees C in a culture medium containing calcium chloride (0.01), potassium dihydrogen phosphate (0.1 g), hydrated magnesium sulfate (0.02), ferrous sulfate (0.01), cobalt chloride (10 microM) and water. The decomposition ratio of caffeine was evaluated by high performance liquid chromatography analysis. 9 strains of microorganism were found to have 100% decomposition ratio. Strain 1 was evaluated to be grown in culture medium containing only caffeine and found to have high caffeine decomposability.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) manufacture of organic substance materials from caffeine containing material using the microorganism Micrococcus sp; and    (2) screening method of microorganisms which involves cultivating microorganism in a culture medium containing caffeine as source of organic nutrition.