[show abstract][hide abstract] ABSTRACT: Two chitinolytic bacterial strains (designated MK2(T) and V7) were isolated from the mycorhizosphere of the fungus Tylopilus felleus. The strains were facultatively anaerobic G(+) endospore formers. Physiological analysis and 16S rRNA gene PCR-RFLP assays revealed nearly identical profiles for both strains, demonstrating their relationship at the species level. Sequences specific for the genus Paenibacillus were found within the 16S rRNA gene sequence of the strain MK2(T). The 16S rRNA gene sequence showed the highest similarity to the sequences of Paenibacillus amylolyticus, P. pabuli and P. xylanilyticus. DNA-DNA relatedness of the strain with the type strain of P. amylolyticus was 4.95 %, of P. pabuli 38.0 %, and of P. xylanilyticus 46.3 %, indicating no relatedness between MK2(T) and any of them at the species level. The most abundant fatty acids in strains MK2(T) and V7 were anteiso-C(15:0), iso-C(16:0), iso-C(15:0) and n-C(16:0). DNA-DNA relatedness, morphological, physiological and chemotaxonomic analyses, and phylogenetic data based on 16S rRNA gene sequencing made it possible to describe both strains as the novel species of the genus Paenibacillus, for which the name Paenibacillus tylopili is proposed, the type strain being MK2(T) (DSM 18927(T), LMG 23975(T)).