(DE4415127-A1)      A process is claimed for the disposal of waste material (I) in which the solid components consist mainly of polyester, polylactide, polylactone and/or polycarbonate plastics, and which is contaminated with potentially infectious biological substances. The process comprises (A) incubating (I) in aq. medium in the presence of micro-organisms (II) and/or (B) heating in aq. alkaline medium until the solid plastic is at least partly dissolved.    Also claimed is micro-organism SK 37 (DSM 8962).    USE -   Micro-organism SK 37 (or micro-organisms with an equiv. power of degradation) is used for the liquefaction of biodegradable plastics in aq. media (claimed). Also claimed is the use of polyhydroxybutyric acid copolymers for the prodn. of plastic laboratory materials (pref. moulded pipette tips, reaction vessels, optical cells and microtitration plates) which are completely biodegradable by micro-organisms within 20 days, and the use of polyhydroxy-fatty acid polymers for the prodn. of such materials which are completely degraded by heating under alkaline conditions for 24 hrs.    ADVANTAGE -   Enables the inexpensive disposal of large amounts of waste plastic material from laboratories, industrial units and hospitals in a reasonable time without using aggressive chemicals and without adverse environmental effects.    (JP8038587-A)      A process is claimed for the disposal of waste material (I) in which the solid components consist mainly of polyester, polylactide, polylactone and/or polycarbonate plastics, and which is contaminated with potentially infectious biological substances. The process comprises (A) incubating (I) in aq. medium in the presence of micro-organisms (II) and/or (B) heating in aq. alkaline medium until the solid plastic is at least partly dissolved.    Also claimed is micro-organism SK 37 (DSM 8962).    USE -   Micro-organism SK 37 (or micro-organisms with an equiv. power of degradation) is used for the liquefaction of biodegradable plastics in aq. media (claimed). Also claimed is the use of polyhydroxybutyric acid copolymers for the prodn. of plastic laboratory materials (pref. moulded pipette tips, reaction vessels, optical cells and microtitration plates) which are completely biodegradable by micro-organisms within 20 days, and the use of polyhydroxy-fatty acid polymers for the prodn. of such materials which are completely degraded by heating under alkaline conditions for 24 hrs.    ADVANTAGE -   Enables the inexpensive disposal of large amounts of waste plastic material from laboratories, industrial units and hospitals in a reasonable time without using aggressive chemicals and without adverse environmental effects.