High-temperature (v60³C) synthetic food waste compost was examined by cultivation-dependent and -independent methods to determine predominant microbial populations. Fluorescent direct counts totaled 6.4 ( þ 2.5)U1010 cells gdw 31 in a freeze-dried 74³C compost sample, while plate counts for thermophilic heterotrophic aerobes averaged 2.6 ( þ 1.0)U10 8 CFU gdw 31 . A pre-lysis cell fractionation method was developed to obtain community DNA and a suite of 16S and 18S rDNA-targeted PCR primers was used to examine the presence of Bacteria, Archaea and fungi. Bacterial 16S rDNA, including a domain-specific 1500-bp fragment and a 300-bp fragment specific for Actinobacteria, was amplified by PCR from all compost samples tested. Archaeal rDNA was not amplified in any sample. Fungal 18S rDNA was only amplified from a separate dairy manure compost that reached a peak temperature of 50³C. Amplified rDNA restriction analysis (ARDRA) was used to screen isolated thermophilic bacteria and a clone library of full-length rDNA fragments. ARDRA screening revealed 14 unique patterns among 63 isolates, with one pattern accounting for 31 of the isolates. In the clone library, 52 unique patterns were detected among 70 clones, indicating high diversity of uncultivated bacteria in hot compost. Phylogenetic analysis revealed that the two most abundant isolates belonged in the genera Aneurinibacillus and Brevibacillus, which are not commonly associated with hot compost. With the exception of one Lactobacillus-type sequence, the clone library contained only sequences that clustered within the genus Bacillus. None of the isolates or cloned sequences could be assigned to the group of obligate thermophilic Bacillus spp. represented by B. stearothermophilus, commonly believed to dominate high-temperature compost. Amplified partial fragments from Actinobacteria, spanning the V3 variable region (Neefs et al. (1990) Nucleic Acids Res. 18, 2237^2242), included sequences related to the genera Saccharomonospora, Gordonia, Rhodococcus and Corynebacterium, although none of these organisms were detected among the isolates or full-length cloned rDNA sequences. All of the thermophilic isolates and sequenced rDNA fragments examined in this study were from Gram-positive organisms. ß

High-temperature (>/=60 degrees C) synthetic food waste compost was examined by cultivation-dependent and -independent methods to determine predominant microbial populations. Fluorescent direct counts totaled 6.4 (+/-2.5)x10(10) cells gdw(-1) in a freeze-dried 74 degrees C compost sample, while plate counts for thermophilic heterotrophic aerobes averaged 2.6 (+/-1.0)x10(8) CFU gdw(-1). A pre-lysis cell fractionation method was developed to obtain community DNA and a suite of 16S and 18S rDNA-targeted PCR primers was used to examine the presence of Bacteria, Archaea and fungi. Bacterial 16S rDNA, including a domain-specific 1500-bp fragment and a 300-bp fragment specific for Actinobacteria, was amplified by PCR from all compost samples tested. Archaeal rDNA was not amplified in any sample. Fungal 18S rDNA was only amplified from a separate dairy manure compost that reached a peak temperature of 50 degrees C. Amplified rDNA restriction analysis (ARDRA) was used to screen isolated thermophilic bacteria and a clone library of full-length rDNA fragments. ARDRA screening revealed 14 unique patterns among 63 isolates, with one pattern accounting for 31 of the isolates. In the clone library, 52 unique patterns were detected among 70 clones, indicating high diversity of uncultivated bacteria in hot compost. Phylogenetic analysis revealed that the two most abundant isolates belonged in the genera Aneurinibacillus and Brevibacillus, which are not commonly associated with hot compost. With the exception of one Lactobacillus-type sequence, the clone library contained only sequences that clustered within the genus Bacillus. None of the isolates or cloned sequences could be assigned to the group of obligate thermophilic Bacillus spp. represented by B. stearothermophilus, commonly believed to dominate high-temperature compost. Amplified partial fragments from Actinobacteria, spanning the V3 variable region (Neefs et al. (1990) Nucleic Acids Res. 18, 2237-2242), included sequences related to the genera Saccharomonospora, Gordonia, Rhodococcus and Corynebacterium, although none of these organisms were detected among the isolates or full-length cloned rDNA sequences. All of the thermophilic isolates and sequenced rDNA fragments examined in this study were from Gram-positive organisms.

Triclosan is a polychlorinated hydroxy diphenylether that has been widely used as an antimicrobial compound. An enrichment using triclosan as a sole source of carbon and energy yielded a consortium of bacteria capable of growing on this compound. The dichloro ring was partially mineralized, resulting in the conversion of approximately 35% of the [(14)C]triclosan to [(14)C]CO(2). Use of molecular fingerprinting techniques and 16S rDNA cloning and sequencing aided in the identification and eventual isolation of an auxotrophic Sphingomonas-like organism, strain Rd1, which was able to partially mineralize triclosan when grown on complex media.