Detection of proteases from Sporosarcina aquimarina and Algoriphagus antarcticus isolated from Antarctic soil

Abstract

Two psychrophilic bacterial samples were isolated from King George Island soil, in Antarctica. The phylogenetic analysis based on the 16S rRNA (rrs) gene led to the correlation with the closest related isolates as Sporosarcina aquimarina (99%) and Algoriphagus antarcticus (99%), with query coverage of 99% and 98%, respectively. The spent culture media from both isolates displayed proteolytic activities detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis containing gelatin as protein substrate. Under the employed conditions, S. aquimarina showed a 55 kDa protease with the best activity detected at pH 7.0 and at 27°C. A. antarcticus also showed a single extracellular protease, however its molecular mass was around 90kDa and its best activity was detected at pH 9.0 and at 37°C. The proteases from both isolates were inhibited by 1,10-phenanthroline and EDTA, two metalloprotease inhibitors. This is the first record of protease detection in both species, and our results may contribute to broaden the basic knowledge of proteases from the Antarctica environment and may help prospecting future biotechnological applications of these enzymes.

Reducing N2O Emission from a Domestic-Strength Nitrifying Culture by Free Nitrous Acid-Based Sludge Treatment

“…For example, the genera of Lysobacter , Pseudomonas , and Algoriphagus were determined in both stages. Previous publications have pointed out that these bacteria can produce and secrete proteases. − These proteases are important enzymes for degrading proteins, which is the main component of the soluble microbial products generated during biomass growth and decay . The degraded substrates can be supplied for the growth of heterotrophic bacteria, although no organic carbon source was included in the synthetic medium.…”

The Variety and Inscrutability of Polar Environments as a Resource of Biotechnologically Relevant Molecules

“…Protease production has been detected for the strains Sporosarcina aquimarina and Algoriphagus antarcticus isolated from Antarctic soil of King George Island. The two proteases, of 55 kDa and 90 kDa exhibited best activity at 27 • C and 37 • C [159]. The proteolytic zymograms suggested their identification as metalloproteases as the only one, with best activity at pH values of 5.0-7.0 for S. aquimarina and 7.0-9.0 for A. antarcticus.…”

Life from a Snowflake: Diversity and Adaptation of Cold-Loving Bacteria among Ice Crystals

“…In addition to this, proteins and enzymes (referred to as cold-active enzymes or psychrozymes) are characterized by a more flexible 3D structure and high catalytic efficiency, necessary to avoid damages in the conformational state and gain better access to the substrate [112]. The functional properties of cold enzymes are due to several structural adaptations, including a peculiar aminoacidic composition (mainly a higher Glu+Asp/Arg+Lys ratio than mesophilic enzymes), reduced amount of some salt bridge-forming amino acids [113,114], presence of weak intramolecular bound interactions (including hydrogen bonds, electrostatic and salt bridges), higher surface hydrophobicity level and negative charge, and reduction in metal binding affinity [115].…”