Ralf Grote

Diversity and cold-active hydrolytic enzymes of culturable bacteria associated with Arctic sea ice, Spitzbergen

The diversity of culturable bacteria associated with sea ice from four permanently cold fjords of Spitzbergen, Arctic Ocean, was investigated. A total of 116 psychrophilic and psychrotolerant strains were isolated under aerobic conditions at 4°C. The isolates were grouped using amplified rDNA restriction analysis fingerprinting and identified by partial sequencing of 16S rRNA gene. The bacterial isolates fell in five phylogenetic groups: subclasses α and γ of Proteobacteria, the Bacillus–Clostridium group, the order Actinomycetales, and the Cytophaga–Flexibacter–Bacteroides (CFB) phylum. Over 70% of the isolates were affiliated with the Proteobacteria γ subclass. Based on phylogenetic analysis (<98% sequence similarity), over 40% of Arctic isolates represent potentially novel species or genera. Most of the isolates were psychrotolerant and grew optimally between 20 and 25°C. Only a few strains were psychrophilic, with an optimal growth at 10–15°C. The majority of the bacterial strains were able to secrete a broad range of cold-active hydrolytic enzymes into the medium at a cultivation temperature of 4°C. The isolates that are able to degrade proteins (skim milk, casein), lipids (olive oil), and polysaccharides (starch, pectin) account for, respectively, 56, 31, and 21% of sea-ice and seawater strains. The temperature dependences for enzyme production during growth and enzymatic activity were determined for two selected enzymes, α-amylase and β-galactosidase. Interestingly, high levels of enzyme productions were measured at growth temperatures between 4 and 10°C, and almost no production was detected at higher temperatures (20–30°C). Catalytic activity was detected even below the freezing point of water (at −5°C), demonstrating the unique properties of these enzymes.

Alicyclobacillus hesperidum sp. nov. and a related genomic species from solfataric soils of São Miguel in the Azores.

Several acidophilic, slightly thermophilic or thermophilic Gram-positive isolates were recovered from solfataric soil at Furnas on the Island of São Miguel in the Azores. Phylogenetic analysis of the 16S rRNA gene sequence showed that these organisms represented two novel species of the genus Alicyclobacillus. Strains FR-11T and FR-1b had an optimum growth temperature of about 50 degrees C, whereas strains FR-3 and FR-6T had an optimum growth temperature of about 60 degrees C. Biochemical, physiological and chemotaxonomic characteristics did not distinguish isolates FR-3 and FR-6T from the type strain of Alicyclobacillus acidocaldarius; however, strains FR-11T and FR-1b could be easily distinguished from the type strain of Alicyclobacillus acidoterrestris by the carbon source assimilation pattern and the fatty acid composition. On the basis of the phylogenetic analysis, physiological and biochemical characteristics, and fatty acid composition the name Alicyclobacillus hesperidum is proposed for the species represented by strains FR-11T and FR-1b; a formal name for the new genomic species represented by strains FR-3 and FR-6T is not proposed at this time.

Thermococcus siculi sp. nov., a novel hyperthermophilic archaeon isolated from a deep-sea hydrothermal vent at the Mid-Okinawa Trough

Abstract A novel coccoid-shaped, hyperthermophilic, anaerobic archaeon, strain RG-20, was isolated from a deep-sea hydrothermal vent fluid sample taken at 1394-m depth at the Mid-Okinawa Trough (27°32.7′N, 126°58.5′E). Cells of this isolate occur singly or in pairs and are about 0.8 to 2 μm in diameter. Growth was observed at temperatures between 50° and 93°C, with an optimum at 85°C. The pH range for growth is 5.0–9.0, with an optimum around 7.0. Strain RG-20 requires 1%–4% of NaCl for growth, and cell lysis occurs at concentrations below 1%. The newly isolated strain grows preferentially in the presence of elemental sulfur on proteinaceous substrates such as yeast extract, peptone, or tryptone, and no growth was observed on carbohydrates, carboxylic acids, alcohols, or lipids. This microorganism is resistant to streptomycin, chloramphenicol, ampicillin, and kanamycin at concentrations up to 150 μg/ml, but is susceptible to rifampicin. Analysis of the hydrolyzed core lipids by thin-layer chromatography (TLC) revealed the presence of archaeol and caldarchaeol. The mol% G+C content of the DNA is 55.8. Partial sequencing of the 16S rDNA indicates that strain RG-20 belongs to the genus Thermococcus. Considering these data and on the basis of the results from DNA-DNA hybridization studies, we propose that this strain should be classified as a new species named Thermococcus siculi (si′cu.li. L. gen. n. siculi, of the deep-sea [siculum, deep-sea in literature of Ovid], referring to the location of the sample site, a deep-sea hydrothermal vent). The type strain is isolate RG-20 (DSM No. 12349).

Thermoanaerobacter yonseiensis sp. nov., a novel extremely thermophilic, xylose-utilizing bacterium that grows at up to 85 degrees C.

A novel strictly anaerobic, extremely thermophilic, spore-forming and xylose-utilizing bacterium, designated strain KB-1TP (type and patent strain), was isolated from a geothermal hot stream at Sileri on Java island, Indonesia. The cells were rod-shaped, motile and had terminal spores. The newly isolated strain stained gram-positive and the cells occurred singly or in pairs during the exponential growth phase. The temperature optimum for growth was 75 degrees C and growth occurred in the range 50-85 degrees C. The pH range for growth was 4.5-9.0, with an optimum at pH 6.5. Strain KB-1TP grew chemo-organotrophically by fermenting a wide range of substrates such as glucose, fructose, D-xylose, lactose, maltose, sucrose, mannose, galactose, cellobiose, pullulan and soluble starch. Arabinose, xylan, cellulose, olive oil and Tween 80 were not fermented. The predominant fermentation end products after growth on glucose were lactate, acetate, ethanol, CO2 and small amounts of isovaleric acid, butyric acid, propionic acid, 1-pentanol and 2-propanol. Thiosulfate was reduced to H2S. Strain KB-1TP was sensitive to tetracycline, chloramphenicol, penicillin G, neomycin, kanamycin, vancomycin and rifampicin at concentrations of 100 microg ml(-1). No effect was observed with chloramphenicol and neomycin at concentrations of 10 microg ml(-1). This indicates that strain KB-1TP belongs to the bacterial domain. The G+C content of the DNA was 37 mol%. The comparison of the 165 rDNA sequence to that of closely related strains revealed that strain KB-1TP belonged to clostridial cluster V, showing highest sequence identities (92.7%) to members of the genus Thermoanaerobacter. Taking into account the physiological and molecular properties of the new isolate, it is proposed that strain KB-1TP should be classified as a new species of the genus Thermoanaerobacter, designated Thermoanaerobacter yonseiensis. The type strain, KB-1TP, has been deposited in the Korean Federation of Culture Collections (KFCC 11116P) as a patent strain and in the Deutsche Sammlung von Mikroorganismen und Zellkulturen as a type strain (= DSM 13777T).

8th International Congress on Biocatalysis (Biocat2016), Hamburg, Germany, 28 August–1 September, 2016

The “8th International Congress on Biocatalysis (biocat2016)” is part of a biennial conference series. Biocatalysis is a topic based on the edge of biology and chemistry, which brings together scientists from the life sciences, engineers and computer scientists. This international conference serves as a platform to meet researchers from all over the world, to find collaboration partners for future projects and to gain novel insights into modern topics and techniques. Biocat covers the most exciting aspects and the latest developments in biocatalysis, including enzyme discovery, evolution and application, bioprocess engineering, cascade reaction systems and nanobiotechnology. In 2016, we welcomed 367 expert delegates in the respective fields. Established and young scientists from academia and the industry presented 51 lectures, 37 lightning talks and 234 posters. In addition, the biocat award, which is among the most prestigious awards in the field of biotechnology, has been awarded for the sixth time in the categories “Science in academia”, “Lifetime achievement” and “Industry”.