Indigenous Peat Cellulolytic Bacteria and Its Potential as A Liberica Coffee Growth Promoter

Among the main microbes in peat are cellulolytic bacteria. The research aimed to select peat cellulolytic bacteria and identified its potential as a plant growth promoter bacteria (PGPB). The cellulolytic bacteria were isolated by serial dilutions and cellulase activity by the carboxymethyl cellulose (CMC) method, species types recognized by the sequencing method and P solubilization and phytohormones productions by Pikovskaya, and the high-performance liquid chromatography method, respectively. Research results found the 1 st identified peat cellulolytic bacteria, Comamonas testosteroni, dissolved fixed P, 1.908 μg PO 4 3- /mL.day and released phytohormones of indole acetic acid (IAA) 0.385 mg/kg, gibberellin (Ga.3) 2.989 mg/kg, zeatin 0.348 mg/kg, and kinetin 0.115 mg/kg. The 2 nd identified bacteria, Delftia lacustris, dissolved fixed P from 1.107 μg PO 4 3- /mL.day to 1.329 μg PO 4 3- /mL.day and produced IAA from 0.775 to 1.161 mg/kg, Ga.3 from 2.551 to 4.429 mg/kg, and zeatin from 0.228 to 1.127 mg/kg and no kinetin. Adding both cellulolytic bacterial colonies on peat improved Liberica coffee seedling growth significantly.