The proposed project leader was the chair of the scientific and organizing committee of the 12th Symposium on Bacterial Genetics and Ecology (BAGECO-12) which took place in Ljubljana, Slovenia, from 9-13 June 2013. BAGECO meetings are held biannually and have developed into one of the most important international conferences on bacterial ecology, with attendance limited to 300 participants and only one session so that participants can hear all the talks. A major motivation of the BAGECO meetings is to open new conceptual avenues leading to better understanding of the ecology and evolution of bacteria in the environment including molecular mechanisms of their interactions that are important for their survival and ecosystem functions. Further details are available at http://www.bageco2013.org . This year’s main slogan is reflected in the title of the meeting “Networking and plasticity of microbial communities: the secret to success” which also reflects the research interests of the chair. To chair this event is an honor and also indicates that the proposed project leader is well respected in the field of microbial ecology. The symposium was a success with almost 300 researchers attending the conference, which further opened the doors for collaborations with best research groups in the world.
B.01 Organiser of a scientific meeting
COBISS.SI-ID: 4259448Bioinformatics has revealed the presence of putative laccase genes in genomes of diverse bacteria, including the strictly anaerobic Geobacter metallireducens GS-15. Laccases (benzenediol:oxygen oxidoreductases, EC 1.10.3.2) are enzymes that catalyse the oxidation of many phenolic and nonphenolic substrates coupled to the reduction of molecular oxygen to water. For this reason, integrity of laccase genes in anaerobes has been questioned. Our goal was to show if one of the putative laccase genes of G. metallireducens GS-15 encodes a functional laccase and, if so, to characterize it. Gmet_2154, one of the five putative laccase genes of G. metallireducens GS-15, was heterologously expressed in Escherichia coli and the resulting protein isolated by using His-tag. The purified enzyme oxidized some of the typical laccase substrates, such as ABTS, 2,6-DMP and syringaldazine. Its temperature optimum was estimated to be 60 °C, and pH optima for ABTS and 2,6-DMP oxidation 5,0 and 8,0, respectively. As with other laccases, the enzymatic activity was inhibited by halide anions. It is possible that Gmet_2154 is also expressed in vivo, but its physiological role in G. metallireducens has not yet been determined. This laccase is the first known laccase originating from a strictly anaerobic microorganism. This work emphasizes the role of bioinformatics in finding novel bacterial laccases.
D.11 Other
COBISS.SI-ID: 7721337Laccases oxidize a variety of phenolic compounds by reducing oxygen to water and are highly interesting for environmental and industrial applications. These enzymes have mostly been studied in fungi where they play a vital role in the degradation of lignocellulose but also shape the morphology and lifestyle of fungi. In contrast, bacterial laccase-like enzymes are poorly understood and only few have been studied extensively. We have recently identified 1,200 genes for putative laccase like enzymes in 2200 draft and completed genomes using custom profile Hidden Markov Models. Up to 76% of laccase genes encoded signal peptides, and many were encoded on plasmids suggesting their mobility within bacterial domain. Two of the identified target genes were purified and characterized in a follow-up study confirming that the identified genes encoded laccases with different (high) pH optima and temperature resilience. This suggested that bacteria indeed represent an underexplored pool of interesting biocatalysts. In addition, metagenomic approaches in collaboration with other partners within the METAEXPLORE project were applied for the bio-mining and exploration of the diversity and activity of laccases.
B.04 Guest lecture
COBISS.SI-ID: 4298616