Abstract

Phenotypic and phylogenetic studies were performed for the facultative alkalophile from the rhizosphere of Ipomoea pes caprae, a plant growing on coastal sand dunes. The isolate was Gram positive and showed optimum growth at pH 10.5. Chemotaxonomic analysis revealed that the isolate contained type B1 peptidoglycans with L-lysine as the diamino acid; rhamnose and galactose were the cell wall sugars and belonged unambiguously to the genus Microbacterium. The major menaquinones were MK-11 and MK-12. The 16S rDNA sequence of the Microbacterium arborescens isolate was deposited in the GenBank with an accession number DQ287961. The phylogenetic and phenotypic distinctiveness of the strain indicates it as a novel Microbacterium sp., named as M. arborescens AGSB.

Key words: facultative alkaliphile, Microbacterium arborescens AGSB, Coastal sand dune vegetation, Ipomoea pes caprae, 16S rRNA sequencing.