Strain Differentiation and Taxonomic Characterisation of a Thermophilic Group of Phenol-degrading Bacilli

Abstract

Thirteen new thermophilic phenol degrading strains were isolated from a number of geographically distinct thermal sources. The strains demonstrated similar growth characteristics with pH optima between 6.0–7.2, temperature optima between 60 °C–70 °C and similar substrate utilisation spectra. The comparison of chromosomal restriction endonuclease, ribotyping and total cellular protein patterns in addition to bacteriocin typing was used for strain differentiation and resulted in the formation of five different groups to which the isolates could be assigned. Eight of the isolates were assigned to group 2 based on identical patterns generated for each method applied. Additional methods such as the comparison of antibiotic MIC values, phenol tolerance, co-metabolic transformation of chlorophenols, fatty acid methyl ester (FAME) patterns and RFLP patterns revealed minor differences between the isolates of group 2. Isolate A2, of this group and A7, which displayed differences using every technique applied, were selected for taxonomic identification and were identified as B. thermoleovorans and B. thermoglucosidasius respectively. This is the first report of phenol degrading isolates belonging to these species.