Isolation, Identification and Screening of Humic Acid Producing Fungi from Soil Environment of Oil palm (Elaeisguineensis) Associated with Empty Fruit Bunches

Abstract

The demand for sustainable and sustainable biotechnological processes has developed as a result of a growing interest in converting agricultural waste into valuable products. In this study, fungal strains were isolated from soil environment of oil palm empty fruit bunches and screened for humic acid production. In Osun state, Nigeria, soil sample was taken from a local palm oil mill. Different colonies of fungi were obtained for further research using the serial dilution plating procedure. Plate screening was used to evaluate the fungal biomass as well as colony diameter of the fungal isolates, and a submerged fermentation test was used to measure the amount of humic acid concentration the isolates produced. Fungal isolates were identified by using molecular methods and morphological analysis. The fungi species Aspergillus niger, Rhizopus stolonifer, and Penicillium chrysogenum were isolated from the soil environment. When compared to Rhizopus stolonifer, Aspergillus niger grew more superiorly in terms of zone diameter (26.5 ± 1.50 mm) and biomass (2.23 ± 0.16 g), while Penicillium chrysogenum showed no growth. Throughout the fermentation process, Aspergillus niger also produced a greater quantity of humic acid, with concentrations varying from 0.70 mg/l to 2.20 mg/l. Aspergillus niger strain HR18's existence was confirmed by molecular analysis. This experiment proved that Aspergillus niger can efficiently produce humic acid from OPEFB, providing a useful method for waste utilization and sustainable practices.