Journal of Environmental Biology

Effect of environmental factors on growth and enzyme production of cold adapted bacteria from water and sedi-ment of Kongsfjord,

Ny-Alesund, Arctic

S. Salam¹, S. Lekshmi¹, R. Silvester¹*, K.P. Krishnan², A.V. Saramma¹ and A.A.M. Hatha¹

¹Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology, Cochin-682 022, India

²National Centre for Antarctic and Ocean Research, Head Land Sada, Vasco-da-Gama, Goa-403 804, India

*Corresponding Author E-mail: sanasilvester@gmail.com

Key words

Bio-prospecting,

Cold-adapted bacteria,

Hydrolytic enzymes,

Psychrotolerant bacteria

Publication Data

Paper received : 07.01.2016

Revised received : 23.05.2016

Re-revised received : 20.10.2016

Accepted : 01.12.2016

Abstract

Aim: The Arctic region has several distinct habitats which makes Arctic a potential region for identifying novel microbial extremophiles. The main objective of the study was to find out the effect of environmental factors such as temperature, pH and salinity on the growth and hydrolytic enzyme production capabilities of psychrotrophic bacteria from the water and sediment of Kongsfjord, Arctic.

Methodology: One hundred and twenty two bacterial isolates from water and sediment of Kongsfjord (79?58′N, 12?E) was obtained for the study. Bacterial isolates were inoculated on ZoBell's Marine medium to study the effect of temperature (4 ^?C, 20 ^?C and 37 ^?C), pH (2-13) and salinity (0.5-4 M) on growth. Effect of temperature on production of extracellular enzymes such as amylase, gelatinase and lipase were checked by plate assay.

Results: All the isolates showed growth at 4 ^?C, 20 ^?C and 37 ^?C; signifying that these isolates were psychrotolerants rather than true psychrophiles. More than 50% of isolates from both water and sediment samples showed growth at wide pH (2-11) range. Salinity tolerance for majority of isolates (54%) of water was 3M and that from sediment varied from 0.5 M to 4 M. Majority of the isolates were capable of producing lipase, followed by gelatinase and amylase. Nearly, all the isolates from water and sediment showed lipolytic activity at 37 ^?C and more than 70% of isolates at 4 ^?C. ?

Interpretation: All the isolates produced one or more enzymes; amylase, lipase or protease at 4 ^?C and (or) 37 ^?C and showed growth at wide pH range and exhibited high salinity tolerance. Thus, the bacteria present in water and sediments of Kongsford are a potential source of novel hydrolytic enzymes, especially lipase that have wide applications in biotechnology, medicine, agriculture, etc.

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