These subsystems (except “Benzoate transport and degradation cluster”) were also considerably more abundant in Tplain and Tpm1-2 than in the other Troll metagenomes (Figure 6). This was also seen in the PCA analysis, where the level I SEED subsystem “Metabolism of Aromatic Compounds” was contributing to the separation of Tplain and Tpm1-2 from the Oslofjord samples (Figure 3). Figure 6 Significant differences in potential for nitrogen and aromatic compound metabolism between Troll and Oslofjord metagenomes. The figure shows differences in level III SEED subsystems involved in metabolism of nitrogen and aromatic compounds where at least one Troll metagenomes was significantly different from both Oslofjord

metagenomes in the STAMP analysis. Troll metagenomes significantly different from the Oslofjord metagenomes are marked by red arrows. Identification of selected key enzymes for hydrocarbon degradation further supported a ABT-263 price higher potential for hydrocarbon degradation KU-60019 purchase in Tplain and Tpm1-2 compared to the other samples (Figure 7). Anaerobic degradation of several aromatic compounds is often funneled through benzoate and benzoyl-CoA by benzoate-CoA ligase and subsequent dearomatization by benzoyl-CoA reductase [34]. The anaerobic activation step of

toluene and several other aromatic hydrocarbons with fumarate addition can be catalyzed by benzylsuccinate synthase. We searched for these anaerobic key enzymes as well as for several dioxygenases involved in aerobic ring-cleavage of the aromatic intermediates catechol, protocatechuate, gentisate and homogentisate. Figure 7 Key genes Cell Penetrating Peptide for hydrocarbon degradation detected. The figure shows reads assigned to a selection of key genes for hydrocarbon degradation

detected in the metagenomes. The reads were identified by search in MG- rast 3; and against a reference library for alkane monooxygenase. Both benzoate-CoA ligase, and several dioxygenases (e.g. protocatechuate 3,4-dioxygenase and homogentisate 1,2-dioxygenase) were overrepresented in the metagenomes from Tplain and Tpm1-2. Alkane 1-monooxygenase (alkB), the key enzyme in alkane degradation, was also seen to be more abundant in Tplain and Tpm1-2 than in the other metagenomes. A few reads assigned to the key genes in anaerobic (methyl-coenzyme M reductase) and aerobic (particulate and soluble methane monooxygenase) methane oxidation were also detected in the Tpm1-2 metagenome. The soluble methane monooxygenase was identified in the metagenomes from Tplain and OF2 as well. An inspection of the level 3 SEED subsystems sorting under “Nitrogen Metabolism” (Figure 6) revealed that “Ammonia assimilation” was overrepresented in all Troll metagenomes, although the difference was only significant for Tplain. This fits well with the overrepresentation of autotrophic nitrifiers in the Troll metagenomes.