Tag: Sequencing

Reports

Traditional skyr. Comparison of home-made and factory-made skyr - Pre-survey / Traditional skyr. Comparison between homemade and industrial produced skyr - Preliminary study

Published:

01/05/2011

Authors:

Þóra Valsdóttir, Eyjólfur Reynisson, Nadine Knocke, Aðalheiður Ólafsdóttir, Þórarinn E. Sveinsson

Supported by:

Agricultural Productivity Fund

Contact

Þóra Valsdóttir

Project Manager

thora.valsdottir@matis.is

Traditional skyr. Comparison of home-made and factory-made skyr - Pre-survey / Traditional skyr. Comparison between homemade and industrial produced skyr - Preliminary study

Skyr is one of the few Icelandic products that can truly be said to be traditional. The few studies that have been done on traditional, home-made skyr, date from the first half of the 20th century. This report presents a preliminary study of home-made and factory-produced skyrs, focusing on the assessment of sensory properties and the analysis of microbial flora using recent genetic methods. Significant differences were detected in sensory factors. The number of lactic acid bacteria and yeasts was considerably higher in home-made skyr. The same types of lactic acid bacteria were detected in different manufacturers and were the same as have been detected in previous studies. Yeasts of the same genus were found on both farms but not in factory-made skyr. Although these are the same bacterial species, it is possible that different phenotypes can be found between farms. Therefore, it would be interesting to investigate the possible metabolic or genotypic variability between strains from different production sites and their effect on the properties of skyr.

Skyr is one of few Icelandic products which can be stated as traditional. Little research has been executed on traditional skyr, of which most from the first part of the 20th century. In this preliminary study, homemade and industrial skyr is compared based on sensory properties and microbiological composition. Significant difference was found on several sensory attributes. Number of lactic acid bacteria and yeasts was much greater in homemade than industrial skyr. Same species of lactic acid bacteria were identified as in previous studies, however only some of previously identified yeast genera were found. Larger part of DNA needs to be sequenced and culture independent methods employed for a more specific identification. Such analysis could provide possibilities on establishing metabolic or genotype difference between different production locations.

Reports

Biodiversity in hot springs in Krísuvík and Gunnuhver in Reykjanes: Research carried out due to the Framework Plan for the utilization of geothermal energy in high-temperature areas

Published:

01/08/2007

Authors:

Sólveig K. Pétursdóttir, Sólveig Ólafsdóttir, Steinunn Magnúsdóttir, Guðmundur Óli Hreggviðsson

Contact

Steinunn Ásbjörg Magnúsdóttir

Project Manager

steinunn.magnusdottir@matis.is

Biodiversity in hot springs in Krísuvík and Gunnuhver in Reykjanes: Research carried out due to the Framework Plan for the utilization of geothermal energy in high-temperature areas

This study of the ecosystem in the hot springs in the Krísuvík area is the third biota assessment carried out within the Framework Program, but the first two dealt with the ecosystem in the hot springs in the Hengill area and in the Torfajökull area.

Emphasis was placed on the thermal area in Seltún, where sampling was joint with the geochemists of the Institute of Earth Sciences, which was the first step in an interdisciplinary approach to the subject, which is hoped for, but is still in its early stages. Other areas that were tried to explore were hot springs by Austurengjahver and the area by Gunnuhver in Reykjanes. The temperature in the hot springs in Seltún was in the range of 53-93 ° C and furthermore one soil sample was reported which was taken at a lower temperature or 34 ° C. The acidity of the hot springs in Seltún was in the range of pH 2.5-6. The temperature in the hot springs at Austurengjahver was between 50-75 ° C and the pH pH 2.4 - 4.3. The temperature in the hot springs at Gunnuhver was measured in the range of 70-90 ° C and the pH pH 3.8 - 4.2. A total of thirteen samples were taken in the above areas and DNA was successfully isolated from seven of them. DNA could not be extracted from the samples at Austurengjahver. Nucleic acid amplification of the 16S rRNA, a species-differentiating gene of the nuclear nucleus, was performed on six samples. Amplification was obtained from all these samples with specific real bacterial indicators, but three with ancient bacterial indicators.

A total of 304 sequences of real bacterial species were obtained in the area known as Seltún. These species are spread over 26 species which in turn are spread over 10 camps. The primitive species of the Aquificeae array house over 80% sequences and are therefore predominant in these samples and are primary producers in the ecosystems of the hot springs. Five species within this array were found in the samples from Seltún. Other species are mainly classified into different groups Proteobacteria (13%) but they are a very diverse group. Other species found are sparsely populated and less important here. A total of 81 sequences of ancient bacterial species were obtained from the Seltún area. Most of them or space 90% are classified as Thermoplasmatales within the Euryarchaeota class, but this is a heat and acid species. Other ancient bacteria in the samples in Seltún belong to the Chrenarchaeota group, mostly to the genus Desulfurococcales.

A total of 56 actual bacterial differentiations were obtained from the hot springs at Gunnuhver. The vast majority of them (about 70%) belong to the primitive class Aquificeae, but about 30% to different groups of Proteobacteria. The ancient bacteria in Gunnuhver are homogeneous as they are all of the genus Sulfolobales which is a very heat and acid group. 1 Overall, it can be said that the area around Seltún shows a typical pattern of a peripheral ecosystem where one species is predominant and other species are spread over various factions. The calculated biodiversity in the samples was relatively low or in the range of 1.0-2.0. For comparison, the same coefficient calculated for samples from the Torfajökull area and at Ölkelduháls was in the range of 1.1-4.7. The environmental conditions of temperature and acidity in Seltún and Gunnuhver are not on the edge, but it is likely that substances and compounds in the hot springs and clay can affect the diversity of the ecosystem, ie. which species get thrive and which do not.

Rare species that had only distant relatives in Genbank were found in the Seltún samples, among others. In most cases, however, there are only 1-2 representatives of the species in question. Most of these distantly related species were classified as Proteobacteria and Acidobacteria.

Matís - Prokaria will probably continue to work on sampling and species analysis in the Krísuvík area. The intention is to include these results in a final summary of the ecosystem in hot springs in Iceland in the last year of the Framework Program.

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