BIODEGRADATION OF THIOPHENE, BENZOTHIOPHENE, AND BENZOFURAN WITH 8 DIFFERENT PRIMARY SUBSTRATES

The aerobic biodegradation of thiophene, benzothiophene, and benzofura n was studied in microcosm experiments using groundwater microorganism s as inoculum. Benzofuran, a heterocyclic aromatic compound containing oxygen, was biodegraded as a sole source of carbon and energy measure d by the disappearance of the compound, whereas two heterocyclic aroma tic compounds containing sulphur (thiophene and benzothiophene) were n ot used as growth substrates. Thiophene was biodegraded with benzene, toluene, and to some extent ethylbenzene as primary substrates. Some b iodegradation of thiophene was observed when p-xylene, o-xylene, m-xyl ene, naphthalene, and 1-methylnaphthalene were the primary substrates. Benzothiophene was completely transformed, with all eight primary sub strates investigated except for benzene and p-xylene, in which 34 and 6% of benzothiophene, respectively, remained after 40 d of incubation. Although benzofuran could be used as a sole source of carbon and ener gy, data showed that the biodegradation of benzofuran definitely was e nhanced by the biodegradation of the primary substrates used.