Substrate RetentionTime (min) m/z of major ion peaks (%)a Suggested structureb Anthracene 18.60 208 (M+, 100), 180 (82), 152 (51), 126 (6), 76 (28) 9,10-anthraquinone Anthracene 17.27  188 (M+, 48), 170 (100), 142 (59), 115 (12), 114 (38), 71 (22) 2-Hydroxy-3-naphthoic acid Anthracene 18.75 224 (M+, 100), 209 (65), 181 (36), 152 (15), 139 (12), 76 (9) 1-methoxy-2-hydroxyanthracene Anthracene 16.72 196 (M+, 100), 168 (35), 139 (38), 98 (7), 84 (6), 70 (14) 6,7-benzocoumarin Naphthalene 9.35 138 (M+, 52), 120 (100), 92 (61), 64 (24) Salicylic aid Naphthalene 7.65 122 (M+, 100), 121 (91), 104 (17), 93 (28), 76 (25), 65 (43) Salicylaldehyde Naphthalene/biphenyl 8.73 110 (M+, 100), 92 (20), 81 (18), 64 (40), 63 (15) Catechol Biphenyl 14.77 122 (78), 105 (M+, 100), 77 (75), 51 (38), Benzoic acid Biphenyl 15.10 186 (M+, 100), 158 (20), 129 (30), 78 (15), 51 (15) 2,3-dihydroxybiphenyl aIon abundance percentages are shown in parentheses. bIdentification was based on the match of mass spectra (fragmentation and peak intensity) and GC retention times, with those of authentic samples.

Table 1: GC-MS data for the metabolites of anthracene, naphthalene and biphenyl, obtained from the organic extracts of the cultures and resting cell incubations of Sphingobium sp. strain PNB.