An agar degrading diazotrophic actinobacteria from hyperalkaline meteoric lonar crater lake - a primary study

Abstract

There are very few reports on agarases being produced by actinobacteria, Streptomyces coelicolor being the only one known since decades for its agar degrading property. Here we report an agar degrading diazotrophic actinobacterium other than Streptomyces coelicolor, isolated from the littoral soil of Lonar Lake situated in Buldhana district of Maharashtra, India, a lake characterised by high alkalinity, carbonates, bicarbonates, and algal blooms. The lake has a mean diameter of 1800 meters. The Gram-positive filamentous rod grew in a simple medium of pH 10.5 containing agar as a sole source of carbon. The agar degrading property was detected by the appearance of depressions around each colony after 48 h of growth. The enzyme responsible for this degradation, agarase was also detected and estimated. The isolate also grew on Ashby’s Nitrogen free Mannitol Medium aerobically and fixed nitrogen. Morphological, physiological and biochemical characteristics of the isolate are presented in this paper.

Keywords

• actinobacterium, agarase, Lonar Lake, algal blooms, depressions.