SPECIFIC MICROORGANISMS - The bacterium belonging to Sphingomonas genus is preferably S. capsulata.    EXAMPLE - River water (500 ml) was filtered using several sheets of membrane filter (0.1-0.5 microm pore size). The obtained filter was dipped in 50 ml polyvinyl alcohol (PVA) culture medium which contained PVA (5 g), ammonium sulfate (1 g), potassium dihydrogen phosphate (0.2 g), di-potassium hydrogen phosphate (1.6 g), magnesium sulfate 7H2O (0.2 g), sodium chloride (0.1 g), calcium chloride 2H2O (0.02 g), ferric sulfate 7H2O (0.01 g), di-sodium molybdate dihydrate (0.5 mg), sodium tungstate dihydrate (0.5 mg), manganese sulfate 5H2O (0.5 mg), calcium pantothenate (0.4 mg), inositol (2 mg), nicotinic acid (0.4 mg), p-aminobenzoic acid (0.2 mg), pyridoxine hydrochloride, thiamine hydrochloride, biotin, cyanocobalamine, pyrroloquinoline-quinone. The culture container containing PVA culture medium was dipped in ultrasonic washing machine and ultrasonication was carried out for 30 seconds-1 minute. The culture medium in the container was aseptically dispensed in 500 ml shaking flask and shaking culture was carried out at 30 degreesC. A part of the culture solution exhibiting turbidity was aseptically inoculated into new PVA culture medium after 2-5 days. The process was repeated 2-3 times and then a part of the culture medium was smeared to a PVA agar medium and culturing was carried out at 30 degreesC. After culturing for 2-5 days, a single colony which showed growth characteristics, was selected from the plate. The colony was identified to be a Sphingomonas capsulata UP-3 strain. The strain was inoculated into a shaking flask containing 50-100 ml PVA culture medium and shaking culture was carried out at 30 degreesC. A part of the culture solution in which the turbidity is increased, was inoculated into new PVA culture medium after 1-2 days and shaking culture was carried out at 30 degreesC. A part of the culture solution was extracted after a certain period of time and turbidity and PVA concentration were measured. The results showed that the novel strain effectively degraded PVA.