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.