Isolation and characterization of Pseudarthrobacter cremeus sp. nov. and Ideonella flava sp. nov. from mountain soil

Two novel bacterial strains, designated as YS3 ^T and YS5 ^T , were isolated from soil collected at Nogo Mountain, Gyeonggi-do, Republic of Korea. Strain YS3 ^T is Gram-positive, aerobic, non-motile and rod-shaped, forming opaque, cream-coloured colonies with smooth surfaces. Phylogenetic analysis based on the 16S rRNA gene sequence revealed the highest similarity to Pseudarthrobacter humi RMG13 ^T (99.2%) and Pseudarthrobacter siccitolerans 4J27 ^T (99.2%). Strain YS3 ^T grew at 4–35 °C (optimum, 30 °C), at pH 4.0–12.0 (optimum, pH 8.0), and tolerated up to 6% (w/v) NaCl, with optimal growth occurring in the absence of NaCl. The genomic G+C content of strain YS3 ^T was 65.0 mol%. Average nucleotide identity (ANI) values between strain YS3 ^T and related Pseudarthrobacter species ranged from 81.2% to 84.9%, while digital DNA–DNA hybridization (dDDH) values ranged from 20.7% to 39.0%. Strain YS5 ^T is Gram-negative, aerobic, motile and rod-shaped, forming translucent, yellow colonies with smooth surfaces. Phylogenetic analysis based on the 16S rRNA gene sequence showed the highest similarity to Ideonella dechloratans CCUG 30898 ^T (98.9%) and Ideonella alba 3Y2 ^T (98.7%). Strain YS5 ^T grew at 10–35 °C (optimum, 30 °C), at pH 4.0–12.0 (optimum, pH 8.0), and tolerated up to 1% (w/v) NaCl, with optimal growth in the absence of NaCl. The genomic G+C content of strain YS5 ^T was 69.0 mol%. ANI values between strain YS5 ^T and Ideonella species ranged from 77.9% to 81.2%, while dDDH values ranged from 15.1% to 22.4%. On the basis of phenotypic, genotypic, phylogenetic and chemotaxonomic evidence, strain YS3 ^T represents a novel species of the genus Pseudarthrobacter , for which the name Pseudarthrobacter cremeus sp. nov. is proposed (type strain YS3 ^T =KACC 24143 ^T =TBRC 21184 ^T ). Similarly, strain YS5 ^T represents a novel species of the genus Ideonella , for which the name Ideonella flava sp. nov. is proposed (type strain YS5 ^T =KACC 24144 ^T =TBRC 21186 ^T ).