Biologically pure cultures of the following microorganism(MO) strains are new: Pseudomonas spp. DAP 70 (ATCC 55646), DAP 111 (ATCC 55645), DAP 622 (ATCC 55648) and DAP 631 (ATCC 55647); Aeromonas spp. DAP 68 (ATCC 55642) and DAP 119 (ATCC 55641); Corynebacterium sp. DPA 66 (ATCC 55643); Zoogloea sp. DAP 73 (ATCC 55649); and Bacteria DAP 623 (ATCC 55722), DAP 626 (ATCC 55723), DAP 115 (ATCC 557234), DAP 120 (ATCC 55725), DAP 629 (ATCC 55727) and DAP 632 (ATCC 55727). Also new is the biologically mixed MO culture DAP 2 (ATCC 55644). Also claimed are: (i) the use of the MO's for aerobically degrading one or more cpd. (I) selected from aromatic, nitroaromatic, haloaromatic, halonitroaromatic, aliphatic and haloaliphatic cpds.; (ii) prodn. of a fluidised compsn. suitable for aerobic reaction from a (I)-contg. elastomeric solid or sludge, by fluidising the solid or sludge, after conversion into particles, in a current of a fluid selected from O2, O2-contg. gas, water and aq. soln.; (iii) prodn. of a slurry from an elastomeric solid or sludge, by combining the solid or sludge, opt. together with a detackifying agent (II), with water or an aq. soln. and imparting energy to fluidise the mixt.; such slurries also being claimed per se; (iv) the use of the above MO's for bioremediation of a neutral slurry contg. MO, specifically where the slurry is prepd. as described in (iii); and (v) the use of the MO's bioremediation of various other forms of waste contg. (I), e.g. solid, sludge or soil which has been mixed with a bulking agent; or waste which has been pretreated with a chemical reagent to convert heavily halogenated or heavily nitrated organic cpds. or heavily nitrated crosslinked polymers into monomeric cpds.; (vi) a biofilter comprising the MO's immobilised on a solid support; and (vii) use of the biofilter for bioremediation of effluents contg. (I).    USE -   (I) is specifically e.g. toluene, xylene, benzene, phenol, cresol, aniline, anthracene, styrene, halonaphthalene, methanol, chloroform, acenaphthalene, m-toluic acid, cinnamyl acetate, mesitylene, chlorotoluene, salicylate, melamine or limonene. The wastes to be bioremediated include elastomeric solids or sludges (after treatment as above), tarry materials, soil, gases, aerosols and liquids. Heavily halogenated cpds. (e.g. polychlorinated or polybrominated biphenyls) and heavily nitrated cpds. (e.g. trinitrotoluene or nitrocellulose) can also be degraded after pretreatment as in (v).    ADVANTAGE -   The MO's rapidly and efficiently degrade a wide range of (I) to CO2 and H2O (claimed), without producing toxic intermediates or by-prods.. They can be stored for long periods (e.g. at least 4 months) without loss of activity, degrade (I) at relatively high concns. (e.g. 1 wt. % or more) and tolerate a wide range of (I) concns. and concn. variations. In combination with pretreatments as in (ii) and (iii), the MO's can be used to degrade (I) in waste materials which are difficult to treat by prior art methods.