Characterization of Streptomyces nymphaeiformis sp. nov., and Its Taxonomic Relatedness to Other Polyhydroxybutyrate-Degrading Streptomycetes

A polyhydroxybutyrate (PHB)-degrading actinomycete, strain SFB5AT, was identified as a species of Streptomyces based on its membrane fatty acid profile and the presence of LL-diaminopimelic acid in the cell wall. It formed sporulating mycelia on most agar media, but flat or wrinkled, moist colonies on trypticase soy agar. Spores were smooth, cylindrical, and borne on long, straight to flexuous chains. It produced a light brown diffusible pigment, but not melanin. Comparison of genomic digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values indicated that strain SFB5AT was related to Streptomyces litmocidini JCM 4394T , Streptomyces vietnamensis GIMV4.0001T , Streptomyces nashvillensis JCM 4498T and Streptomyces tanashiensis JCM 4086T , plus 11 other species. However, the dDDH and ANI values were well below the species differentiation thresholds of \u3c70 and \u3c95%, respectively; also, multilocus sequence analysis distances exceeded the species threshold of 0.007. Moreover, strain SFB5AT differed from the other species in pigmentation and its ability to catabolize arabinose. Strain SFB5AT and 11 of its 15 closest relatives degraded PHB and have genes for extracellular, short-chain-length denatured polyhydroxyalkanoate depolymerases. These enzymes from strain SFB5AT and its closest relatives had a type 1 catalytic domain structure, while those from other relatives had a type 2 structure, which differs from type one in the position of a consensus histidine in the active site. Thus, phenotypic and genotypic differences suggest that strain SFB5AT represents a new species of Streptomyces, for which we propose the name Streptomyces nymphaeiformis sp. nov. The type strain is SFB5AT (=NRRL B-65520T =DSM 112030T )

THE REHABILITATION OF A CONCRETE PAVEMENT USING IN-PLACE RUBBLIZATION AND COLD RECYCLING TECHNOLOGIES

ABSTRACT In 1998, a 19 km portion of Highway 2 located between Woodstock and Thamesford was transferred from the provincial jurisdiction to the County of Oxford, Ontario. County Road 2 was a concrete pavement with 75 mm of hot mix asphalt surfacing. The pavement serviceability was considered poor mainly due to the multiple active joints and rocking of the concrete slabs. In 1999, the County of Oxford made the decision to restore the serviceability of the new County Road 2 using a rehabilitation method that would provide smooth ride, mitigate cracking and eliminate the rocking effect of the concrete slabs. The retained rehabilitation strategy included rubblization of the concrete pavement, cold recycling of the old hot mix asphalt surfacing and placement of new hot mix asphalt surfacing. The rehabilitation of County Road 2 was carried out in three phases and the last phase was completed in the summer of 2001. The experience acquired with every phase of work contributed to define and optimized a construction method that minimizes both, the rehabilitation costs and the construction risks associated with the break up of the concrete pavement structure. This paper presents an overview of the approach undertaken by the County of Oxford to establish a pavement rehabilitation strategy and the step taken to optimize the usage of rubblization and cold recycling of the old hot mix asphalt surfacing