Isolation and characterization of novel alkali-halophilic actinomycetes from the Chilika brackish water lake, India

Abstract

The current investigation deals with isolation and functional characterization of agriculturally important novel alkali-halophilic actinomycetes from water and sediment samples of three distinct niches, namely, central, south and sea mouth sectors of the Chilika brackish water lake. A total of 59 different morphotypes based on phenotypic characterization were isolated from different sectors of the lake. Among them, a total of twenty one isolates were screened as alkali-halophiles based on screening for salt and pH tolerance on starch casein agar medium amended with 10 % NaCl and at pH 9.0. Further characterization for plant growth promotion and biocontrol attributes revealed that the south sector harboured a maximum percentage of siderophore producers while the central sector had the highest indole 3-acetic acid as well as extracellular protease producers. The sea mouth sector had a higher portion of actinomycetes possessing nitrate reductase activity and some biocontrol attributes such as antimicrobial activity against fungal pathogens (Rhizoctonia solani, Fusarium udum and Fusarium oxysporum f. sp. ciceri) and production of chitinase enzyme. Identification including 16S rRNA gene sequences revealed that isolates belonged to the Streptomyces and Micromonospora genera, respectively.