Evaluation of actinomycetes abundance and isolation of phytate degrading actinomycetes in different soil ecosystems

Actinomycetes are widely distributed in different habitats and involved in important processes. Therefore, evaluation of their distribution is important in understanding their ecological role. Many soil microorganisms (including actinomycetes) are able to transform different forms of insoluble organic and inorganic phosphorus into a soluble form suitable for plant uptake. The objective of this study was enumeration of common actinomycetes and determination of their phytate degradation by spectrophotometry and High Performance Liquid Chromatography (HPLC) methods. Ninty seven soil samples were collected from different soil ecosystems from the province of Golestan, Iran. The initial screening was made on modified glycerol arginin agar (MGAA) to isolate common actinomycetes and modified MGA-SE (MMGA-SE) for rare actinomycetes. The enumeration of common actinomycetes was achieved on GAA. Actinomycetes colony formed on GAA in different land use was significantly different (P<0.001) and climate variation affected some soil factors and actinomycetes number. Irrigated cultivated and pasture soils had maximum and minimum number of actinomycetes, respectively. The phosphate release was confirmed in liquid culture for 46.3% of the isolates. The selected isolates showed phytate-degrading activity and their capabilities was strongly dependent on media composition. A huge variation in the capacity to degrade phytate (1.65-95.2%) among different isolates was observed.