Phylogenetic and physiological characterization of mesophilic and thermophilic bacteria from a sewage sludge composting process in Sapporo, Japan

Abstract

The phylogenetic and physiological characteristics of mesophilic and thermophilic bacteria isolated from a field-scale sewage sludge composter were determined by 16S rDNA and phenotype analyses. Of the 34 mesophilic isolates, 5 (15%), 16 (47%), and 3 (9%) displayed amylase, protease, and lipase activities, respectively. Among these isolates, the following species were identified based on their 16S rRNA gene sequences: Aneurinibacillus aneurinilyticus, Bacillus fortis, Bacillus subtilis, Brachybacterium paraconglomeratum, Brevibacterium otitidis, Dietzia maris, Pseudomonas xiamenensis, Staphylococcus lentus, Thermobifida fusca, Ureibacillus thermosphaericus, and Vagococcus lutrae. However, 15 isolates could not be identified as known taxa, thus indicating new bacterial taxa. Of these new taxa, it is likely that NoID A plays an important role in organic matter decomposition during composting based on its physiological characteristics. Sapporo sewage sludge compost contains a microbial ecosystem with novel bacterial biodiversity, comprising a high percentage of previously unrecognized species. This study improves our knowledge of the unique bacteria in sewage sludge compost, providing a future resource for bacterial genetic information and bacterial species of agricultural benefit.

Examination and Comparison of Microbial Diversity in Field-Scale Sewage Sludge Composters

“…Hence, the main phylogenetic groups of bacteria that actively contribute to the composting process under each temperature condition vary according to the phylum level. The same tendency was observed for Sapporo Compost (Ohnishi et al, 2011 (Fig. 1).…”

“…Most strains of B. subtilis were able to utilize 23 sole carbon sources, which were mainly carbohydrates, polymers, carboxylic acids, and alcohols. The hydrolysis of starch and casein has also been observed for members of this group (Ohnishi et al, 2011). In addition, B. subtilis may inhibit fungal growth when compost is applied to agricultural land (Phae et al, 1990).…”

“…In addition, B. subtilis may inhibit fungal growth when compost is applied to agricultural land (Phae et al, 1990). The "NoID D" group can also hydrolyze casein (Ohnishi et al, 2011), and utilize 17 sole carbon sources, which primarily include carboxylic acid, amino acid, and nucleoside. However, this group shows weak ability to utilize carbohydrate.…”

“…The amplified 16S rRNA gene was directly sequenced using an ABI PRISM BigDye Terminator Cycle Sequencing Ready Reaction kit and an ABI PRISM model 310 Genetic Analyzer (Applied Biosystems). The following 5 primers were used: 20F, 1540R, 350F (5′-CCTACGGGAGGCAGCAGT-3′, positions 341-358), 800F (5′-GTAGTCCACGCCGTAAACGA-3′, positions 803-819), and 900R (5′-CGGCCGTACTCCCCAGGCGG-3′, positions 879-898) (Ohnishi et al, 2011).…”

“…Our research group previously used the culture-dependent approach to provide important information about unknown microbial diversity and potential available resources in a fieldscale model of a sewage sludge composter that was set up in Sapporo, Japan (Ohnishi et al, 2011). During composting, microorganisms decompose solid wastes, such as urban wastes, sewage sludge, and food garbage.…”