A Gram-stain-negative, aerobic, rod-shaped, non-motile, non-spore-forming bacterial strain, designated J22 T , was isolated from fresh pasta filled with pork (tortellini) that had been stored at 6 6C. Based on 16S rRNA gene sequence analysis, strain J22T falls within the radiation of species of the genus Pedobacter. On the basis of 16S rRNA gene sequence similarities, the closest species phylogenetically are Pedobacter panaciterrae LMG 23400 T (98.7 %), Pedobacter africanus DSM 12126 T (98.5 %) and Pedobacter heparinus DSM 2366 T (98.3 %). The only isoprenoid quinone of strain J22 T was menaquinone 7 (MK-7). The major fatty acids were iso-C 15 : 0 (34.8 %), C 16 : 1 cis9 (24.9 %), C 16 : 0 (7.3 %), C 14 : 0 (4.8 %) and iso-C 17 : 0 3-OH (4.4 %). These chemotaxonomic characteristics supported the assignment of the isolate to the genus Pedobacter. DNA-DNA hybridization experiments showed that the DNA-DNA relatedness between strain J22 T and its closest phylogenetic neighbour, Pedobacter panaciterrae LMG 23400 T , was less than 36 %. This indicated that the isolate was distinct from this species. Biochemical tests allowed strain J22T to be phenotypically differentiated from closely related species of the genus Pedobacter. As a consequence, strain J22 T should be classified as a representative of a novel species of the genus Pedobacter for which the name Pedobacter nutrimenti sp. nov. is proposed. The type strain is J22 T (5DSM 27372 T 5CCUG 64422 T ).

Five isolates from chilled food and refrigerator inner surfaces and closely related reference strains of the species Escherichia coli, Listeria monocytogenes, Staphylococcus xylosus, Bacillus cereus, Pedobacter nutrimenti, and Pedobacter panaciterrae were tested for the effect of growth temperature (30°C and 10°C) on biomass formation. Growth was monitored via optical density, and biomass formation was measured at the early stationary phase based on the following parameters in complex and defined media: viable cell count, total cell count, cell dry weight, whole-cell protein content, and cell morphology. According to the lack of growth at 1°C, all strains were assigned to the thermal class of mesophiles. Glucose and ammonium consumption related to cell yield were analyzed in defined media. Except for the protein content, temperature had a significant (t test, P < 0.05) effect on all biomass formation parameters for each strain. The results show a significant difference between the isolates and the related reference strains. Isolates achieved an increase in biomass production between 20% and 110% at the 10°C temperature, which is 15 to 25°C lower than their maximum growth rate temperatures. In contrast, reference strains showed a maximum increase of only about 25%, and some reference strains showed no increase or a decrease of approximately 25%. As expected, growth rates for all strains were higher at 30°C than at 10°C, while biomass production for isolates was higher at 10°C than at 30°C. In contrast, the reference strains showed similar growth yields at the two temperatures. This also demonstrates for mesophilic bacterial strains more efficient nutrient assimilation during growth at low temperatures. Until now, this characteristic was attributed only to psychrophilic microorganisms. IMPORTANCEFor several psychrophilic species, increased biomass formation was described at temperatures lower than optimum growth temperatures, which are defined by the highest growth rate. This work shows increased biomass formation at low growth temperatures for mesophilic isolates. A comparison with closely related reference strains from culture collections showed a significantly smaller increase or no increase in biomass formation. This indicates a loss of specific adaptive mechanisms (e.g., cold adaptation) for mesophiles during long-term cultivation. The increased biomass production for mesophiles under low-temperature conditions opens new avenues for a more efficient biotechnological transformation of nutrients to microbial biomass. These findings may also be important for risk assessment of cooled foods since risk potential is often correlated with the cell numbers present in food samples.T emperature has an obvious influence on the physiological functions and, consequently, on the growth and survival of bacteria (1, 2). Accordingly, bacteria have adapted to the specific temperature ranges of various environments, which can be summarized in different temperature classes.Cold-adapted microorganisms are classified as ps...