Corrosive Lesions at Concrete Infrastructures as Promising Source for Isolating Bioactive Actinobacteria

Abstract

The aim of this paper is isolating rare actinobacteria from new ecological source as corrosive lesion at concrete infrastructure and screening their ability to produce biological products. Ten pure actinobacteria isolates were isolated from corrosive lesions at concrete infrastructures of irrigation channel using cement extract media at different pHs (9- 12) and incubated at 30°C for 7d. All of the isolates produced variable levels of cellulase and lipase, and nine of them displayed variable levels of alkaline protease and amylase products. Only Four isolates produced extracellular alkaline phosphatase in liquid media. The antagonistic activities of these isolates were screened against four pathogenic microorganisms including Gram positive and negative bacterial species and two species of fungi. Only the isolate ROR40 exhibited antagonism activity against Staphylococcus aureus and Escherichia coli , whereas nine isolates showed different degrees of antagonism activities against Microsporum canis and Trichophyton mentagrophyte. The potential isolate (ROR40) to produce extracellular alkaline phosphatase was selected and identified depending on phenotypical, physiological and molecular according to partial sequences of 16S r RNA gene. It had 98% similarity with Pseudonocardia alni 20049 and P. alni 44104. Finally the isolate is named Pseudonocardia sp. ROR40 (Genbank accession no KJ 725072). The isolate produced extracellular alkaline phosphatase in liquid medium at optimum conditions were pH 8.5 of production medium, 37 °C for 4d. in stand incubator. Conclusion: Our study would be the first instance in comprehensive characterization of concert deteriorating actinobacteria for producing commercially valuable primary and secondary metabolites and it may facilitate us to isolate and characterize more bioactive species.