Isolasi dan Identifikasi Jamur Pelarut Fosfat dan Kalium dari Limbah Kulit Jengkol (Pithecellobium jiringa)

Abstract

Jengkol (Pithecellobium jiringa) is widely used as a food source, but it produces peel waste that is not yet optimally utilized and may cause environmental pollution. The peel has a distinctive and pungent aroma, formed due to the transformation of jengkolic acid into sulfur-containing compounds. Jengkol peel contains jengkolic acid, a major compound of sulfur-containing amino acids that lowers pH, thereby facilitating the solubilization of phosphate and potassium. It also contains phenolic compounds, tannins, alkaloids, flavonoids, and essential nutrients such as potassium, phosphorus, calcium, magnesium, and sulfur that support the growth of microbes and plants. Phosphorus and potassium are essential macronutrients, but their availability in soil is often limited because phosphorus binds in forms such as Al-P, Fe-P, and Ca-P, while potassium exists in mineral forms that are not readily absorbed by plants. Phosphate- and potassium-solubilizing fungi have been proven to increase the availability of these nutrients through environmentally friendly approaches, including the use of jengkol peel waste. This study aimed to isolate and identify phosphate- and potassium-solubilizing fungi from jengkol peel waste. The research was conducted at the Soil Biology Laboratory, Agrotechnology Study Program, Faculty of Agriculture, Universitas Sumatera Utara, using an experimental method involving the isolation and identification of fungi from jengkol peel waste, utilizing available laboratory equipment and materials. The identified phosphate-solubilizing fungi were Penicillium sp., Aspergillus niger, Aspergillus fumigatus, and Aspergillus flavus, while the potassium-solubilizing fungi were Penicillium sp. and Aspergillus niger. The solubilization activity of each fungus was indicated by the presence of a clear zone around the fungal colony, with each isolate showing a different solubilization index.