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Rhizobial nitrogen-fixing bacteria are the main inhabitants of the root nodules of legume plants. Studying the bacterial community of legume nodules is important in understanding plant growth and nutrient requirements. Culture-based technique was used to examine the bacterial community of these underground organs from Vigna subterranea L. Verdc (Bambara nut), an underutilized legume in Africa, for plant growth-promoting traits. In this study, Bambara nuts were planted to trap root-nodule bacteria, and the bacteria were morphologically, biochemically, and molecularly characterized. Five selected isolates were screened in vitro for their plant growth-promoting traits and exhibited differences in their phenotypic traits. The polymerase chain reaction (PCR) products were subjected to partial 16S rRNA gene sequencing for phylogenetic analysis. Based on 16S rRNA gene sequence, the isolates were identified as BA1 (Stenotrophomonas maltophilia), BA2 (Chryseobacterium sp.), BA3 (Pseudomonas alcaligenes), BA4 (Pseudomonas plecoglossicida), and BA5 (Pseudomonas hibiscicola). Results showed that four of the five isolates could produce IAA. The capability to solubilize phosphate in Pikovskaya's agar plates was positively shown by four isolates (BA2, BA3, BA4, and BA5). Three isolates could produce hydrogen cyanide while isolates BA1, BA3, BA4, and BA5 were found to have ammonia-production traits. The results suggest that these plant growth-promoting isolates can be used as inoculants for plant growth and productivity. [ABSTRACT FROM AUTHOR]

Lignin recalcitrance is a key issue in producing value-added products from lignocellulose biomass. In situ biodegradable lignin-modifying enzymes-producing bacteria are considered a suitable solution to lignin biodegradation problems, but exploitation of ligninolytic bacteria is still limited to date. Hence, this study aimed to isolate and characterize potential lignin peroxidase ligninolytic bacteria from decomposing soil, sawdust, and cow dung at Richard Bay, South Africa. The samples were collected and cultured in the lignin-enriched medium. Pure isolated colonies were characterized through 16S rRNA gene sequencing. The ability of the isolates to grow and utilize aromatic monomers (veratryl and guaiacol alcohol) and decolorize lignin-like dyes (Azure B, Congo Red, Remazol Brilliant Blue R) was evaluated. Of the twenty-six (26) bacteria isolates 10 isolates, including Pseudomonas spp. (88%), Enterobacter spp. (8%), and Escherichia coli (4%) were identified as true lignin peroxidase producers. Pseudomonas aeruginosa (CP031449.2) and E. coli (LR025096.1) exhibited the highest ligninolytic activities. These isolates could potentially be exploited in the industry and wastewater treatment as effective lignin degrading agents. [ABSTRACT FROM AUTHOR]