Isolation and Identification of Potential Bio-Inoculants Based on Phosphate Solubilizing Molds From Different Plant Rhizospheres

Abstract

In crop production, phosphorus (P) is the second most important limiting nutrient. However, due to precipitation reactions with Al3+, Fe3+ in acidic soil, or Ca2+ in alkaline soil, its availability in soil is severely limited. Microbes have recently been proposed as a means of increasing the bioavailability of soil phosphate for plants. The goal of this research was to isolate and identify phosphate solubilizing molds (PSM) from various plant rhizospheres, including gadung (Dioscorea hispida Dennst), maize (Zea mays L.), bamboo (Dendrocalamus asper), pineapple (Ananas comosus L.), and banana (Ananas indica L.). PSM was isolated in vitro and then diluted using the dilution plate technique with Pikovskaya’s solid medium. Five colonies were confirmed as PSM, namely Talaromyces aculeatus, Metarhizium anisopliae, Fusarium proliferatum, Mucor hiemalis, and Aspergillus niger, out of fourteen colonies formed from those rhizospheres. In the PVK solid medium, these isolates were capable of solubilizing insoluble P with a solubility range of 2.05 to 3.03. Talaromyces aculeatus (125.6 mg L-1), Metarhizium anisopliae (80.76 mg L-1) and Fusarium proliferatum (41.59 mg L-1) were the best P solubilizers, followed by Mucor hiemalis (9.51 mg L-1), and Aspergillus niger (7.85 mg L-1), respectively. The bioinoculants Talaromyces aculeatus and Metarhizium anisopliae had the most potential.
 Keywords: Dendrocalamus asper, Molds, Phosphate, Rhizosphere, Solubilizer