Paenibacillus sinensis sp. nov., a nitrogen-fixing species isolated from plant rhizospheres

Paenibacillus mesotrionivorans sp. nov., a Mesotrione-Degrading Strain Isolated from Soil

A Gram-stain-positive, facultatively anaerobic, motile with peritrichous flagella, and rod-shaped bacterium, designated as P15T, was isolated from an agricultural soil sample collected in Jiangxi Province, PR China. Strain P15T completely degraded 100 mg/L of mesotrione, a herbicide, within 48 h of incubation. Strain P15T grew at 15-42 °C (optimum 30 °C), pH 6.0-9.0 (optimum 7.0), and 0-4.0% (w/v) NaCl (optimum 1.0%). Strain P15T exhibited less than 93.3% 16S rRNA gene sequence similarity with type strains of genus Paenibacillus. In the phylogenetic tree based on 16S rRNA gene sequences, strain P15T was clustered in genus Paenibacillus and formed a subclade with P. cavernae C4-5T, P. contaminans CKOBP-6T, and P. doosanensis CAU 1005T. The major cellular fatty acids (≥ 5% of the total) were anteiso-C15:0, iso-C16:0, C14:0, C16:0, and iso-C14:0. The predominant respiratory quinone was MK-7. The major polar lipids were diphosphatidylglycerol, phosphatidylglycero, phosphatidylethanolamine, one unidentified glycolipid, one unidentified aminophosphoglycolipid, two unidentified aminophospholipids, two unidentified phospholipid, and two unidentified lipids. The diagnostic diamino acid of the peptidoglycan was meso-diaminopimelic acid. The DNA G + C content was 53.9 mol%. Based on the phylogenetic, phenotypic, and chemotaxonomic characteristics, strain P15T represents a novel species within genus Paenibacillus, for which the name Paenibacillus mesotrionivorans sp. nov is proposed, with strain P15T (= MCCC 1K09191T = KCTC 43705T) as the type strain.

Nitrogen-Fixing Paenibacillus haidiansis and Paenibacillus sanfengchensis: Two Novel Species from Plant Rhizospheres

Two strains, M1 and H32 with nitrogen-fixing ability, were isolated from the rhizospheres of different plants. Genome sequence analysis showed that a nif (nitrogen fixation) gene cluster composed of nine genes (nifB nifH nifD nifK nifE nifN nifX hesA nifV) was conserved in the two strains. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strains M1 and H32 are members of the genus Paenibacillus. Strains M1 and H32 had 97% similarity in the 16S rRNA gene sequences. Strain M1 had the highest similarity (97.25%) with Paenibacillus vini LAM 0504T in the 16S rRNA gene sequences. Strain H32 had the highest similarity (97.48%) with Paenibacillus faecis TCIP 101062T in the 16S rRNA gene sequences. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain M1 and its closest member P. vini were 78.17% and 22.3%, respectively. ANI and dDDH values between strain H32 and its closest member P. faecis were 88.94% and 66.02%, respectively. The predominant fatty acid of both strains is anteiso-C15:0. The major polar lipids of both strains are DPG (diphosphatidylglycerol) and PG (phosphatidylglycerol). The predominant isoprenoid quinone of both strains is MK-7. With all the phylogenetic and phenotypic divergency, two novel species Paenibacillus haidiansis sp. nov and Paenibacillus sanfengchensis sp. nov are proposed with the type strain M1T [=GDMCC (Guangdong Culture Collection Centre of Microbiology) 1.4871 = JCM (Japan Collection of Microorganisms) 37487] and with type strain H32T (=GDMCC 1.4872 = JCM37488).

Microbial cell factories using Paenibacillus: status and perspectives

Considered a "Generally Recognized As Safe" (GRAS) bacterium, the plant growth-promoting rhizobacterium Paenibacillus has been widely applied in: agriculture, medicine, industry, and environmental remediation. Paenibacillus species not only accelerate plant growth and degrade toxic substances in wastewater and soil but also produce industrially-relevant enzymes and antimicrobial peptides. Due to a lack of genetic manipulation tools and methods, exploitation of the bioresources of naturally isolated Paenibacillus species has long been limited. Genetic manipulation tools and methods continue to improve in Paenibacillus, such as shuttle plasmids, promoters, and genetic tools of CRISPR. Furthermore, genetic transformation systems develop gradually, including: penicillin-mediated transformation, electroporation, and magnesium amino acid-mediated transformation. As genetic manipulation methods of homologous recombination and CRISPR-mediated editing system have developed gradually, Paenibacillus has come to be regarded as a promising microbial chassis for biomanufacturing, expanding its application scope, such as: industrial enzymes, bioremediation and bioadsorption, surfactants, and antibacterial agents. In this review, we describe the applications of Paenibacillus bioproducts, and then discuss recent advances and future challenges in the development of genetic manipulation systems in this genus. This work highlights the potential of Paenibacillus as a new microbial chassis for mining bioresources.

Paenibacillus glufosinatiresistens sp. nov., a glufosinate-resistant bacterium isolated from sludge

A Gram-stain-positive bacterium capable of resisting 5.0 mM glufosinate, designated strain YX-27T, was isolated from a sludge sample collected from a factory in Wuxi, Jiangsu, PR China. Cells were rod-shaped, facultatively anaerobic, endospore-forming, and motile by peritrichous flagella. Growth was observed at 15-42 °C (optimum at 30 °C), pH 4.0-8.0 (optimum pH 7.0-7.5) and with 0-2.5% NaCl (w/v; optimum, 0.5 %). Strain YX-27T could tolerate up to 6.0 mM glufosinate. Strain YX-27T showed the highest 16S rRNA gene sequence similarity to Paenibacillus tianjinensis TB2019T (96.17 %), followed by Paenibacillus odorifer DSM 1539T (96.15 %), Paenibacillus sophorae S27T (96.04 %), Paenibacillus apii 7124T (96.02 %) and Paenibacillus stellifer DSM 14472T (95.87 %). The phylogenetic tree based on genome and 16S rRNA gene sequences indicated that strain YX-27T was clustered in the genus Paenibacillus but formed a separate clade. The genome size of YX-27T was 5.22 Mb with a G+C content of 57.5 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between the genomes of strain YX-27T and 12 closely related type strains ranged from 70.8 to 74.8% and 19.8 to 23.0 %, respectively. The major cellular fatty acids were C16 : 0, anteiso-C15 : 0 and iso-C16 : 0. The major polar lipids were one diphosphatidylglycerol, one phosphatidylethanolamine, one phosphatidylglycerol, one phospholipid, four aminophospholipids and four unidentified lipids. The predominant respiratory quinone was MK-7. Based on phylogenetic, genomic, chemotaxonomic and phenotypic data, strain YX-27T was considered to represent a novel species for which the name Paenibacillus glufosinatiresistens sp. nov. is proposed, with YX-27T (=MCCC 1K08803T= KCTC 43611T) as the type strain.

Paenibacillus piscarius sp. nov., a novel nitrogen-fixing species isolated from the gut of the armored catfish Parotocinclus maculicauda

A Gram-positive, nitrogen-fixing and endospore-forming strain, designated P121^T, was isolated from the gut of the armored catfish (Parotocinclus maculicauda) and identified as a member of the genus Paenibacillus based on the sequences of the 16S rRNA encoding gene, rpoB, gyrB and nifH genes and phenotypic analyses. The most closely related species to strain P121^T were Paenibacillus rhizoplanae DSM 103993^T, Paenibacillus silagei DSM 101953^T and Paenibacillus borealis DSM 13188^T, with similarity values of 98.9, 98.3 and 97.6%, respectively, based on 16S rRNA gene sequences. Genome sequencing revealed a genome size of 7,513,698 bp, DNA G + C content of 53.9 mol% and the presence of the structural nitrogenase encoding genes (nifK, nifD and nifH) and of other nif genes necessary for nitrogen fixation. Digital DNA-DNA hybridization (dDDH) experiments and average nucleotide identity (ANI) analyses between strain P121^T and the type strains of the closest species demonstrated that the highest values were below the thresholds of 70% dDDH (42.3% with P. borealis) and 95% ANI (84.28% with P. silagei) for bacterial species delineation, indicating that strain P121^T represents a distinct species. Its major cellular fatty acid was anteiso-C_15:0 (42.4%), and the major isoprenoid quinone was MK-7. Based on physiological, genomic, biochemical and chemotaxonomic characteristics, we propose that strain P121^T represents a novel species for which the name Paenibacillus piscarius sp. nov. is proposed (type strain = DSM 25072 = LFB-Fiocruz 1636).