Characterization and identification of compost bacteria based on 16S rRNA gene sequencing

• Published in: Annals of microbiology Vol. 63; no. 3; pp. 905 - 912
• Main Authors: Hayat, Rifat, Sheirdil, Rizwan Ali, Iftikhar-ul-Hassan, Muhammad, Ahmed, Iftikhar
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2013
• Subjects: Applied Microbiology; Biomedical and Life Sciences; Life Sciences; Medical Microbiology; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Mycology; Original Article; PGPR; 16S rRNA gene sequence; Wheat growth; Compost bacteria
• ISSN: 1590-4261; 1869-2044
• DOI: 10.1007/s13213-012-0542-4

The aim of this study was to isolate and characterize bacteria from the compost of fruit and vegetable waste (FVW) for plant growth-promoting (PGP) activities and investigate the pro-active influence of bacterial isolates on wheat growth. Fourteen bacterial strains (RHC-1 to RHC-14) were isolated and purified in tryptic soya agar (TSA). In addition to being biochemically characterized, these bacterial strains were also tested for their PGP traits, such as phosphate (P)-solubilization, nif H gene amplification, indole-3-acetic acid (IAA) quantification and the production of ammonia, oxidase and catalase. Based on 16S rRNA gene sequencing, these bacterial strains were identified as belonging to species of Bacillus , Lysinibacillus , Lysobacter , Staphylococcus , Enterobacter , Pseudomonas and Serratia . All bacterial strains solubilized tri-calcium phosphate and produced IAA. Two bacterial strains RHC-8 ( Enterobacter sp.) and RHC-13 ( Pseudomonas sp.) solubilized the maximum amount of tri-calcium phosphate, i.e. 486 and 464 μg/ml, respectively. P-solubilization was associated with a significant drop in the pH of the broth culture from an initial pH of 7 to pH 4.43. In addition to P-solubilization and IAA production, six bacterial strains also carried the nif H gene and were further evaluated for their effect on wheat ( Triticum aestivum ) growth under controlled conditions. All six bacterial strains enhanced wheat growth as compared to uninoculated control plants. Two of the bacterial strains, RHC-8 and RHC-13, identified as Enterobacter aerogenes and Pseudomonas brenneri , respectively, were assessed as potential PGP rhizobacteria due to exhibiting characteristics of four or more PGP traits and enhancing wheat growth though their specific mechanism of action.