Job, Daniel

2015, Simon, Anaele, Bindschedler, Saskia, Job, Daniel, Wick, Lukas Y., Filippidou, Sevasti, Kooli, Wafa M., Verrecchia, Eric P., Junier, Pilar

Fungi and bacteria form various associations that are central to numerous environmental processes. In the so-called fungal highway, bacteria disperse along fungal mycelium. We developed a novel tool for the in situ isolation of bacteria moving along fungal hyphae as well as for the recovery of fungi potentially involved in dispersal, both of which are attracted towards a target culture medium. We present the validation and the results of the first in situ test. Couples of fungi and bacteria were isolated from soil. Amongst the enriched organisms, we identified several species of fast-growing fungi (Fusarium sp. and Chaetomium sp.), as well as various potentially associated bacterial groups, including Variovorax soli, Olivibacter soli, Acinetobacter calcoaceticus, and several species of the genera Stenotrophomonas, Achromobacter and Ochrobactrum. Migration of bacteria along fungal hyphae across a discontinuous medium was confirmed in most of the cases. Although the majority of the bacteria for which migration was confirmed were also positive for flagellar motility, not all motile bacteria dispersed using their potential fungal partner. In addition, the importance of hydrophobicity of the fungal mycelial surface was confirmed. Future applications of the columns include targeting different types of microorganisms and their interactions, either by enrichment or by state of the art molecular biological methods.

2011-10-21, Job, Daniel

2010-6-15, Job, Daniel

2009-6-15, Job, Daniel

2013, Bravo, Daniel, Cailleau, Guillaume, Bindschedler, Saskia, Simon, Anaele, Job, Daniel, Verrecchia, Eric, Junier, Pilar

2011-10-10, Job, Daniel

2010-6-15, Job, Daniel

2013, Joseph, Edith, Letardi, Paola, Junier, Pilar, Simon, Anaele, Comensoli, Lucrezia, Job, Daniel, Wörle, Marie

We propose an innovative treatment by which the protection of copper-based artefacts can be provided by naturally occurring microorganisms. The properties of some fungi were exploited for the transformation of existing corrosion patinas into copper oxalates. The latter are known to be insoluble and chemically stable. Within the earlier EU-ARTECH and BAHAMAS projects, very promising results were obtained with an almost 100% conversion from copper hydroxysulfates and hydroxychlorides into copper oxalates. A fungal strain was used which had been isolated from vineyard soil heavily contaminated with copper. Further scientific investigations were carried out to determine the parameters of the process and allowing the formation of a reproducible and homogeneous patina of copper oxalates, called biopatina to highlight its biological origin. Particular attention was paid to the efficacy, durability and impact on colour of the newly developed treatment. Different copper and bronze coupons with either urban or marine patinas were prepared. Several analytical techniques were used for the characterisation of the patinas: Fourier Transform InfraRed microspectroscopy (µFTIR), colourimetry and Electrochemical Impedance Spectroscopy (EIS). The coupons were treated with either the biological treatment or reference materials (wax: Cosmoloid H80; silane: Dynasylan® F8263) and exposed to atmospheric corrosion (ISMAR-SMS Genoa Harbour, corrosivity class 5) in December 2011. The long-term behaviour and performance of the treatments under study was monitored and compared over a one year period using the same complement of analytical techniques used for the characterisation of the original patinas. These first measurements suggested a different weathering behaviour of the biopatina. In fact, in comparison to the silane and wax treatments the biopatina showed a lower colour variation, and a corrosion stabilisation process seemed to be in progress. A deeper analysis of colour and corrosion rate variation from different application methods was also achieved. The complete assessment of the different treatments will be finished this year.

2011-6-15, Job, Daniel

2010, Job, Daniel