Microbial Diversity and Enzymes in Ikaite Columns: A Cold and Alkaline Environment in Greenland

Vester, Jan Kjølhede; Lylloff, Jeanette E.; Glaring, Mikkel A.; Stougaard, Peter

doi:10.1007/978-94-007-6488-0_15

Cited by 5 publications

(6 citation statements)

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“…The Ikka fjord in SW Greenland harbours a unique assemblage of underwater tufa columns composed of the hexa‐hydrated carbonate mineral ikaite (Pauly, ; Buchardt et al ., ), which forms a porous matrix harbouring a diverse assemblage of microbes (Stougaard et al ., ; Vester et al ., ; Glaring et al ., ). Hundreds of columns are situated in the innermost part of the Ikka fjord in South‐western Greenland (Seaman and Buchardt, ), while ikaite column formation or larger solid ikaite assemblages have not been documented from other locations.…”

Section: Introductionmentioning

confidence: 97%

“…The microbiology of ikaite tufa columns has been studied over several years, albeit with a strong focus on mapping the microbial diversity and obtaining bacterial cultures with biotechnological potential, e.g., bacteria harbouring cold‐active enzymes. These studies have mainly focused on heterotrophic bacteria, and sampling has often been done on more solid older parts of tufa columns at water depths with low light exposure (Stougaard et al ., ; Schmidt et al ., ; Vester et al ., ). Stougaard et al .…”

Section: Introductionmentioning

confidence: 97%

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Phototrophic microbes form endolithic biofilms in ikaite tufa columns (SW Greenland)

Trampe

Castenholz

Larsen

et al. 2017

Environmental Microbiology

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Marine tufa-columns, formed by the hydrated carbonate mineral ikaite, present a unique alkaline microbial habitat only found in Ikka Fjord (SW-Greenland). The outermost parts of the ikaite columns exhibit a multitude of physico-chemical gradients, and the porous ikaite is colonized by endolithic phototrophic biofilms serving as a substrate for grazing epifauna, where scraping by sea urchins affects overall column-topography. We present a detailed study of the optical microenvironment, spatial organization, and photosynthetic activity of endolithic phototrophs within the porous ikaite crystal matrix. Cyanobacteria and diatoms formed distinctly coloured zones and were closely associated with ikaite-crystals via excretion of exopolymers. Scalar-irradiance measurements showed strong attenuation of visible light (400-700 nm), where only ∼1% of incident irradiance remained at 20 mm depth. Transmission spectra showed in vivo absorption signatures of diatom and cyanobacterial photopigments, which were confirmed by HPLC-analysis. Variable-chlorophyll-fluorescence-imaging showed active photosynthesis with high-light acclimation in the outer diatom layer, and low-light acclimation in the underlying cyanobacterial part. Phototrophs in ikaite thus thrive in polymer-bound endolithic biofilms in a complex gradient microhabitat experiencing constant slow percolation of highly alkaline phosphate-enriched spring water mixing with cold seawater at the tufa-column-apex. We discuss the potential role of these biofilms in ikaite column formation.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Phototrophic microbes form endolithic biofilms in ikaite tufa columns (SW Greenland)

Trampe

Castenholz

Larsen

et al. 2017

Environmental Microbiology

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“…So far, four new bacterial strains with cold-active enzymes have been described in detail; the α-amylase- and protease-producing Arsukibacterium ikkense [ 18 ], the α-amylase-, α-, β-galactosidase- and β-glucuronidase-producing Alkalilactibacillus ikkensis [ 19 ], the phosphatase-, esterase-, protease- and β-galactosidase-producing Rhodonellum psychrophilum [ 20 ] as well as a lipase-producing γ-Proteobacterium [ 21 ]. Work conducted during the last decade on the ecology and microbial enzymes from the ikaite columns has recently been reviewed, highlighting the ikaite columns as a unique biological environment with good prospects for finding novel bacterial species and enzymes for industrial applications [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

Discovery of novel enzymes with industrial potential from a cold and alkaline environment by a combination of functional metagenomics and culturing

2014

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BackgroundThe use of cold-active enzymes has many advantages, including reduced energy consumption and easy inactivation. The ikaite columns of SW Greenland are permanently cold (4-6°C) and alkaline (above pH 10), and the microorganisms living there and their enzymes are adapted to these conditions. Since only a small fraction of the total microbial diversity can be cultured in the laboratory, a combined approach involving functional screening of a strain collection and a metagenomic library was undertaken for discovery of novel enzymes from the ikaite columns.ResultsA strain collection with 322 cultured isolates was screened for enzymatic activities identifying a large number of enzyme producers, with a high re-discovery rate to previously characterized strains. A functional expression library established in Escherichia coli identified a number of novel cold-active enzymes. Both α-amylases and β-galactosidases were characterized in more detail with respect to temperature and pH profiles and one of the β-galactosidases, BGalI17E2, was able to hydrolyze lactose at 5°C. A metagenome sequence of the expression library indicated that the majority of enzymatic activities were not detected by functional expression. Phylogenetic analysis showed that different bacterial communities were targeted with the culture dependent and independent approaches and revealed the bias of multiple displacement amplification (MDA) of DNA isolated from complex microbial communities.ConclusionsMany cold- and/or alkaline-active enzymes of industrial relevance were identified in the culture based approach and the majority of the enzyme-producing isolates were closely related to previously characterized strains. The function-based metagenomic approach, on the other hand, identified several enzymes (β-galactosidases, α-amylases and a phosphatase) with low homology to known sequences that were easily expressed in the production host E. coli. The β-galactosidase BGalI17E2 was able to hydrolyze lactose at low temperature, suggesting a possibly use in the dairy industry for this enzyme. The two different approaches complemented each other by targeting different microbial communities, highlighting the usefulness of combining methods for bioprospecting. Finally, we document here that ikaite columns constitute an important source of cold- and/or alkaline-active enzymes with industrial application potential.

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“…Cold and alkaline environments are rare on Earth, and knowledge regarding the organisms that thrive in such polyextreme environments is very limited. The submarine ikaite tufa columns in the Ikka Fjord in southwest Greenland (61°11′N, 48°01′W) represent a unique, permanently cold (4 to 6°C), and alkaline (>pH 10) environment ( 1 ), and they have been shown to harbor a diverse bacterial community adapted to these conditions ( 2 – 4 ). A large number of bacteria from the ikaite columns have previously been isolated, and the majority of these are psychrotolerant and alkaliphilic or alkalitolerant ( 2 – 4 ).…”

Section: Genome Announcementmentioning

confidence: 99%

“…The submarine ikaite tufa columns in the Ikka Fjord in southwest Greenland (61°11′N, 48°01′W) represent a unique, permanently cold (4 to 6°C), and alkaline (>pH 10) environment ( 1 ), and they have been shown to harbor a diverse bacterial community adapted to these conditions ( 2 – 4 ). A large number of bacteria from the ikaite columns have previously been isolated, and the majority of these are psychrotolerant and alkaliphilic or alkalitolerant ( 2 – 4 ). Although a significant number of the isolates display alkaliphilic and psychrotolerant growth properties, only very few true alkaliphilic psychrophiles have been identified.…”

Section: Genome Announcementmentioning

confidence: 99%

Draft Genome Sequence of the Psychrophilic and Alkaliphilic Rhodonellum psychrophilum Strain GCM71 ^T

et al. 2013

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Microbial Diversity and Enzymes in Ikaite Columns: A Cold and Alkaline Environment in Greenland

Cited by 5 publications

References 32 publications

Phototrophic microbes form endolithic biofilms in ikaite tufa columns (SW Greenland)

Phototrophic microbes form endolithic biofilms in ikaite tufa columns (SW Greenland)

Discovery of novel enzymes with industrial potential from a cold and alkaline environment by a combination of functional metagenomics and culturing

Draft Genome Sequence of the Psychrophilic and Alkaliphilic Rhodonellum psychrophilum Strain GCM71 ^T

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Microbial Diversity and Enzymes in Ikaite Columns: A Cold and Alkaline Environment in Greenland

Cited by 5 publications

References 32 publications

Phototrophic microbes form endolithic biofilms in ikaite tufa columns (SW Greenland)

Phototrophic microbes form endolithic biofilms in ikaite tufa columns (SW Greenland)

Discovery of novel enzymes with industrial potential from a cold and alkaline environment by a combination of functional metagenomics and culturing

Draft Genome Sequence of the Psychrophilic and Alkaliphilic Rhodonellum psychrophilum Strain GCM71 T

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Draft Genome Sequence of the Psychrophilic and Alkaliphilic Rhodonellum psychrophilum Strain GCM71 ^T