Screening and Characterization of Thermolabile Protease and Alkaliphilic Lipase Producing Psychrotrophic Stenotrophomonas sp.and Pseudomonas sp.

The study was performed to isolate cold active alkaline protease and alkaline active lipase producing psychrotrophic bacteria from water and soil samples collected from different glaciers of Karakorum Range of mountains, Pakistan. Serial dilution and plating approaches were exploited for bacterial isolation and the isolates were qualitatively screened for proteolytic and lipolytic activity with skim milk and Tributyrin agar (TBA plate) assay method. From the collected samples, a total of 20 bacterial isolates (PAK-01 to PAK-20) were exhibiting psychrotrophic physiology. About 8 isolates were capable of proteolysis in alkaline range of pH; and 6 bacteria exhibited lipolysis. Based upon primary and secondary qualitative screening, One isolate (PAK-01) exhibited maximum proteolysis on 1 % skim milk while another isolate (PAK-03) demonstrated maximum lipolysis on Tributyrin Plate Assay. On the basis of morpho-physiology, biochemistry and 16s rRNA sequence, the PAK- 01 was identified as Stenotrophomonas sp. MG662181 and PAK-03 was identified and tagged as Pseudomonas sp. MG687270. Based upon genetic signatures and physiological parameters, our strain presented less than 79% of homology to Stenotrophomonas sp. and Pseudomonas sp. which makes it a novel species. Both of the strains were nonpathogenic and potentially industrial strains for the production of thermolabile protease and alkaliphilic lipase.