Preliminary identification of dehalogenation specificities exhibited by dehalorespiring bacteria from a marine microbial community

The ability of a previously PCB-enriched microbial culture from Venice Lagoon marine sediments to dechlorinate pentachlorophenol (PCP) and 2,3,5-trichlorophenol (2,3,5-TCP) was confirmed under anaerobic conditions in microcosms consisting of site water and sediment. Dechlorination activities against Aroclor 1254 PCB mixture were also confirmed as control. Pentachlorophenol was degraded to 2,4,6-TCP (75.92±0.85 mol%), 3,5-DCP (6.40±0.75 mol%), and phenol (15.40±0.87 mol%). From the distribution of the different dechlorination products accumulated in the PCP-spiked cultures over time, two dechlorination pathways for PCP were proposed: (i) PCP to 2,3,4,6-TeCP, then to 2,4,6-TCP through the removal of both meta double-flanked chlorine substituents (main pathway); (ii) alternately, PCP to 2,3,5,6-TeCP, 2,3,5-TCP, 3,5-DCP, then phenol, through the removal of the para double-flanked chlorine, followed by ortho single-flanked chlorines, and finally meta unflanked chlorines (minor pathway). Removal of meta double-flanked chlorines is thus preferred over all other substituents. 2,3,5-TCP, that completely lacks double-flanked chlorines, was degraded to 3,5-DCP through removal of the ortho single-flanked chlorine, with a 99.6% reduction in initial concentration of 2,3,5-TCP by week 14. 16S rRNA PCR-DGGE using Chloroflexi-specific primers revealed a different role of the two microorganisms VLD-1 and VLD-2, previously identified as dechlorinators in the Aroclor 1254 PCB-enriched community, in the dehalogenation of chlorophenols. VLD-1 was observed both in PCP- and TCP-dechlorinating communities, whereas VLD-2 only in TCP-dechlorinating communities. This indicates that VLD-1 and VLD-2 may both dechlorinate ortho single-flanked chlorines, but only VLD-1 is able to remove double-flanked meta or para chlorines.

Sea organisms as a source of collagen-derived polymers for skin tissue engineering applications

Advanced therapies combating acute and chronic skin wounds are likely to be brought about using our knowledge of regenerative medicine coupled with appropriately tissue engineered skin substitutes. At the present time, there are no models of an artificial skin that completely replicate normal uninjured skin and they are usually accompanied by fibrotic reactions that result in the production of a scar. Natural biopolymers such as collagen have been a lot investigated as potential source of biomaterial for skin replacement in Tissue Engineering. Collagens are the most abundant high molecular weight proteins in both invertebrate and vertebrate organisms, including mammals, and possess mainly a structural role in connective tissues. From this, they have been elected as one of the key biological materials in tissue regeneration approaches, as skin tissue engineering. In addition, industry is constantly searching for new natural sources of collagen and upgraded methodologies for their production. The most common sources are skin and bone from bovine and porcine origin. However, these last carry high risk of bovine spongiform encephalopathy or transmissible spongiform encephalopathy and immunogenic responses. On the other hand, the increase of jellyfish has led us to consider this marine organism as potential collagen source for tissue engineering applications. In the present study, novel form of acid and pepsin soluble collagen were extracted from dried Rhopilema hispidum jellyfish species in an effort to obtain an alternative and safer collagen. We studied different methods of collagen purification (tissues and experimental procedures). The best collagen yield was obtained using pepsin extraction method (34.16 mg collagen/g of tissue). The isolated collagen was characterized by SDS-polyacrylamide gel electrophoresis and circular dichroism spectroscopy.

Advanced Non-Destructive Inspections focused on composite materials application for the automotive and marine sectors

The goal of this master thesis is to explain in detail the application of Non-Destructive-Inspection on the Automotive and the Marine sectors. Nowadays, these two particular industries faces many challenges, including increased global competition, the need for higher performance, a reduction in costs and tighter environmental and safety requirements. The materials used for these applications play key roles in overcoming these challenges. So, also an NDI procedure need to be planned in order to avoid problems during the manufacturing process and the after sale life of the structures. The entire thesis work has been done in collaboration with Vetorix Engineering.