In these study lignins from different lignocellulosic fibres (jute, sisal and coconut) were used. Different preparation (wax, ethanol/water solubles and pectic substances removal) procedures were used to achieve the best conditions for lignin analysis. Lignin was isolated using modified soda pulping treatment followed by enzymatic hydrolysis to achieve the highest purity and structure integrity as possible. Enzymatic modification of isolated lignins was further performed using two different types of laccases, i.e. bacterial and fungal origin. Differences in lignin structure before and after the enzymatic treatment were evaluated with spectroscopic methods as ATR-FTIR, UV-VIS and XPS spectroscopy. Additionally, average particle size and surface charge of lignins were evaluated.
COBISS.SI-ID: 16659734
In this work genes for laccase-like enzymes were searched for in over 2,200 complete and draft bacterial genomes and four metagenomic datasets, using the custom profile Hidden Markov Models for two- and three- domain laccases. For the first time more than 1,200 putative genes for laccase-like enzymes belonging to three and two domain laccases were retrieved from chromosomes and plasmids of diverse bacteria. In 76% of the genes, signal peptides were predicted, indicating that these bacterial laccases may be exported from the cytoplasm, which was in contrast with the current belief and therefore a very novel insight. Moreover, several examples of putatively horizontally transferred bacterial laccase genes were described for the first time. Many metagenomic sequences encoding fragments of laccase-like enzymes could not be phylogenetically assigned, indicating considerable novelty. Laccase-like genes were also found in anaerobic bacteria, autotrophs and alkaliphiles, thus opening new hypotheses regarding their ecological functions. The work has been already cited as indicated in Google Scholar 19 times.
COBISS.SI-ID: 3993720
This is a pioneering work published in the top journal (1/31 in soil science= on diversity of bacterial laccases in soil, which demonstrates that laccases are widespread in bacteria and may be more important than fungal laccases. A new primer was constructed to retrieve larger fragments of the putative bacterial laccase genes and both “conventional” 3-domain laccases and the recently described 2-domain small laccases were obtained, demonstrating the potential of the primer for discovering laccase-like sequences in bacterial strains and in environmental samples.
COBISS.SI-ID: 3874680
In these study lignins from different lignocellulosic fibres (jute, sisal and coconut) were isolated with combined chemical/bio-chemical procedure in order to achieve the highest purity and structure integrity as possible. Enzymatic activation and modification of isolated lignins were further performed using two different types of laccases, i.e. bacterial and fungal origin. In order to determine the differences in lignin structure before and after an enzymatic treatment different spectroscopic methods as ATR-FTIR, UV-VIS and XPS spectroscopy were used. Additionally, average particle size and surface charge of lignins were evaluated using zetasizer.
COBISS.SI-ID: 16657686
The article is in large part devoted to the laccase activity in the presence of phenolic-like substances. Several chemical and physical methods for the characterisation of the catalytic activity of laccases, and for the description of the kinetics and final products of the action of these enzymes on various lignocellulosic surfaces were used. The knowledge of the analytical methods and the acquired information on laccase function were an essential base for the utilisation of these enzymes for the functionalisation of lignocellulosic surfaces.
COBISS.SI-ID: 2159753