The PGPR Revolution: Empowering Porang Plant Growth with Cellulolytic-Hydrolizing, Nitrogen-Fixing, and Phosphate-Solubilizing Prodigies

Abstract

Abstract Porang rhizosphere harbors a diverse range of bacteria, which play pivotal roles in driving essential soil processes that, in turn, regulate the overall functionality of terrestrial ecosystems. This study primarily focuses on the PGPR (Plant Growth-Promoting Rhizobacteria) properties of these strains, which possess cellulolytic, nitrogen-fixing, and phosphate-solubilizing abilities. The research was carried out by isolating bacteria from the porang rhizosphere. The isolated bacteria were then tested for their ability to hydrolyze cellulose, fix nitrogen and dissolve phosphate. Apart from that, a capability test was also carried out in producing IAA. Isolate UPc22 consistently exhibited higher cellulolytic activity, as evidenced by both cellulose hydrolyzing efficiency cellulase activity and IAA production. UPn24 demonstrated the most active nitrogen-fixing activity, with consistently higher mean values for both activity efficiency and nitrogenase activity quantification. UPp36 displayed notably high phosphate-solubilization efficiency values in plate assays. In enzymatic assays, isolate UPp36 exhibited the highest activity. Based on that assays, 15 potential isolates were selected for each group. For cellulolytic bacteria, the selected isolates were similar with Rhizobium cellulosilyticum Strain H349, Paenibacillus pinihumi Strain CM6, Stenotrophomonas maltophilia Strain JCM 1988, Paenibacillus cellulositrophicus Strain P-21, and Bacillus thuringiensis Strain RG17-11. For nitrogen-fixing bacteria, the chosen isolates comprise Azotobacter vinelandii Strain PWB, Delftia lacustris Strain R-54356, Bacillus subtilis Strain A14d3B, Pseudomonas stutzeri Strain DSM 5190T, and Klebsiella quasipneumoniae Strain KqPF26. For phosphate-solubilizing bacteria, the selected isolates was similar with Pseudomonas putida Strain GPo1, Bacillus magterium Strain WF6, Bacillus licheniformis Strain 51.5, Klebsiella singaporensis Strain 01A065, and Burkholderia cepacia Strain PRS.