MARZymes - about MARZymes
Marine microorganisms represent a huge and unexplored resource for cold-adapted enzymes. MARZymes is all about this; finding marine enzymes which are adapted to extreme conditions in the arctic area - we call them molecules for the future
Collecting samples from the Barents Sea
Marine organisms in the arctic region harbours cold-adapted enzymes that display a higher specific activity at low temperatures.Some of these microorganisms are found in the gut and intestines of marine animals in the Barents Sea and Arctic Ocean.To harvest interesting organisms we prepare cruises with the University of Tromsø research ship, FF Helmer Hanssen, previously known as FF Jan Mayen (photo). FF Helmer Hanssen is a multipurpose vessel, designed for fishery and marine biological, geological and oceanographic surveys, and can go in both open and even ice covered waters (1-2 m drift ice).
FF Helmer Hanssen is equipped with modern instruments, and has special designed features for improved acoustic surveying and bottom sediment sampling. One of the tools for collecting sediment samples, the grab, is shown below (photo). Read more about the ship.
Culturing bacteria from the sediment samples
Some of these microorganisms can be cultured in our lab. We grow the bacteria on thin layer of agar-based medium, and we incubate them on low temperatures. To get large bacterial cultures for experimentation, we pick colonies (spots on plate) and grow them in liquid cultures. Later, we can purify the DNA from the bacterial clones, and analyse it.
We assume, however, that only about 5-10 % of these microorganisms can be grown on plates. Using next-generation sequencing technologies it is possible to study the DNA also in uncultured environmental samples (metagenomics).
Finding gene sequences that code for interesting enzymes
In addition to a cultured bacterial collection, we have prepared a metagenomic fosmid library of sediment samples from the arctic Barents Sea for de novo sequencing. By in silico screening of the gene sequences we have identified candidate cold-adapted enzymes. Some of these targets have been produced recombinantly in E. coli, and will be characterized functionally. So far, our focus has been put on enzyme activities that are relevant for applications in biotechnology and food industry, and for the development and processing of biofuels. Although novel enzymatic activities will be discovered, most enzymes will reveal new specificities, activities and stabilities compared to already known homologues. Of special interest are cold-adapted and/or salt-tolerant proteins, due to their high catalytic activity at low temperatures and stability in organic solvents, respectively. Heat-lability, which ensures a fast and efficient inactivation of the enzyme, is also of great importance. As an example, homologues of carbohydrate-active enzymes, some of which are involved in plant cell wall degradation, have been found in the marine sediments. Biomass conversion to biofuels may be one potential application for these enzymes, next to pulp and paper industry and food processing industry.
Last updated: 21.08.2013 12:51