Cultural Diversity of Psychrophilic Bacteria from Different Glaciers of Karakoram Mountain Range and Role of Cell Membrane Fatty Acids in Cold Adaptation

Abstract

The Karakoram Mountain Range (KMR) is one of the largest mountain ranges in the world, with ~ 37% of its area glaciated. Here, we present the geochemistry of ice, sediment and meltwaters sampled from Ghulmet, Ghulkin and Hopar glaciers of the Karakoram Range, Pakistan, in addition to the first information on the diversity of pigmented bacteria evaluated using culture-dependent techniques. Geochemical analyses revealed Ca2+ and SO42– to be the most abundant cation and anion species across all glacial samples, respectively. Total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) were found in large quantity in the sediments of all glaciers studied in current research. Bacterial species were capable of producing a variety of different pigments, including alloxanthin, astaxanthin, bacterioruberin, β–carotene, 19'–hexanoyloxyfucoxanthin, peridinin, violacein and zeaxanthin. In addition, unknown pigments were also found to be produced by bacterial isolates. Culturable bacterial diversity was studied using two molecular biomarkers, 16S rRNA and rpoB gene, with a total of 82 bacterial strains representing 25 genera identified across all glacial samples. This study provides the first characterization of glacier-associated, pigment-producing bacterial communities from the KMR. Findings are important for considerations of alternative sources of conventional pigment production in industrial fields.