Two newly isolated aniline-degrading bacterial strains were characterized with regard to their enzyme systems responsible for aniline catabolism. One of them identified as a Rhodococcus sp. metabolized aniline exclusively via the ,3-ketoadipate pathway by means of inducible enzymes. The aniline-degrading enzyme system of the second isolate, presumably a pseudomonad, was shown to consist of an inducible aniline-converting enzyme and constitutive meta-pathway enzymes. Both isolates failed to metabolize monochlorinated anilines in the absence of additional carbon sources. To explain this the ring-cleaving enzymes of both isolates were examined for their substrate specificities. Furthermore, the effect of 4-chlorocatechol on the enzymes catalyzing aniline conversion and catechol oxygenation was investigated.Microbial degradation of phenyl amides is of environmental relevance. Thus aniline and its derivatives can be found among the waste products of certain chemical industries. I n agricultural soils treated with herbicides of the phenyl amide type (phenylureas, phenylcarbamates, acylanilides) , chloroanilines are formed by microbial transformation of the man-made chemicals. I n some cases the chloroanilines which may react to produce hazardous azocompounds (BARTHA and PRAMER 1970) when accumulated in soil proved to be even more persistent than the applied herbicides.Soil bacteria capable of utilizing aniline as sole source of carbon, nitrogen, and energy normally fail to degrade chlorinated anilines. However, some of them do metabolize these compounds in the presence of additional energy-providing carbon sources (RE-BER et al. Materials and methodsIsolation of the bacterial strains and their identification are described in the experimental part. Cultivation: Both strains An 117 and SB 3 were maintained a t 4 "C on agar slants using the R (rich)-medium of KAZUHIKO and KOMAGATA (1972). Liquid cultures were grown a t 28 "C in a mineral salts medium containing per litre: 9.0 g Na2HP04-12 H,O, 1.5 g KH,PO,, 0.2 g MgSO,.7 H,O, 0.01 g CaCl,, 0.0025 g FeSO, * 7 H,O, 0.5 mg H,BO,, 0.1 mg KJ, 0.4 mg MnSO, -4 H20, 0.4 mg ZnSO, * 7 H,O, 0.2 mg Na2Mo0, * 2 H20, 0.1 mg CuSO, 5 H,O; pH was 6.9. When carbon sources other than aniline were used as substrates, the medium was supplemented with 1 g/lNH,NO,. Nature and concentration of the carbon sources used are mentioned in the experimental part.Cell-free extracts: Crude extracts were prepared as described by SALA-TREPAT and EVANS (1971) without the high-speed centrifugation step. The protein was estimated by the method of LOWRY et al. (1951) using bovine serum albumin as standard.Enzyme assays : The activity of catechol2,3-dioxygenase (metapyrocatechase, EC 1.13.1.2) was determined according to NOZAKI (1970). The activity of the enzymes metabolizing 2-hydroxymu-

Two newly isolated aniline-degrading bacterial strains were characterized with regard to their enzyme systems responsible for aniline catabolism. One of them identified as a Rhodococcus sp. metabolized aniline exclusively via the beta-ketoadipate pathway by means of inducible enzymes. The aniline-degrading enzyme system of the second isolate, presumably a pseudomonad, was shown to consist of an inducible aniline-converting enzyme and constitutive meta-pathway enzymes. Both isolates failed to metabolize monochlorinated anilines in the absence of additional carbon sources. To explain this the ring-cleaving enzymes of both isolates were examined for their substrate specificities. Furthermore, the effect of 4-chlorocatechol on the enzymes catalyzing aniline conversion and catechol oxygenation was investigated.

Comparative experiments were conducted to examine undefined methanogenic consortia from Saale river sediment acclimated to either 0-, m-or p-cresol for their potential to degrade different aromatic compounds.Each of the consortia under study proved specifically acclimated with respect to the particular cresol isomer used as the substrate during the enrichment procedure and failed to deal with any of the dimethylphenols tested. These findings clearly indicate that the enzyme systems initiating anaerobic (methanogenic) degradation of the different cresol (monomethylphenol) isomers are characterized by a narrow substrate speciDegradation of the particular cresol isomers was accompanied by production of methane in amounts which correspond to 89-97 "/, of the theoretically possible yield. In addition, several exogenously added structural analogues ( e g benzoate, 2-, 3-and Chydroxybenzoic acid, guaiacol, catechol) were degraded with high rates after short acclimation periods or even without any initial delay, depending on the particular type of consortium used.Distinct patterns of degradative activity towards the different aromatic test substrates were observed for the cresol-acclimated bacterial consortia under study. The results obtained are insufficient to specblaie about the precise degradation routes involved. They provide clear-cut evidence, however, that use of mixtures of methanogenic consortia like those from Saale river sediment acclimated to 0-, rn-andp-cresol, respectively. would allow relatively fast biodegradation of a wide range of aromatic compounds under anaerobic (methanogenic) conditions. ficity.Phenolics are riskful waste products from chemical industries (e.g. polymeric resin production, oil refining) and coal conversion processing. Currently, there is a growing interest in applying anaerobic processes for biological treatment of wastewaters containing phenolic materials, mainly because of economic reasons (no aeration required; low sludge production compared to aerobic processes; biogas production). Since the early reports of CHMIELOWSKI and his coworkers (CHMIELOWSKI et al. 1965, CHMIELOWSKI and WASI-LEWSKI 1966), many other workers have documented the potential of methanogenic consortia to deal with phenolics. Alkylphenols, however, proved rather recalcitrant in this respect as compared to other aromatic compounds.The ability of methanogenic consortia from different sources to degrade p-cresol to CH, andCO, has been well established while there are contradictory reports in the literature concerning methanogenic degradation of o-and m-cresol. For example, CHMII: LOWSKI et ul. (1965)