CoNISMa, Consorzio Nazionale Interuniversitario Scienze del Mare Partner 1c DISTAM Università degli Studi di Milano Daniele Daffonchio Tullio Brusa Sara Borin Adriana Bona Enrica Canzi Claudia Sorlini WP5: understanding of ecological relations between the microbial communities and the functioning of DHABs environment

Oil utilisation as unique carbon source Catechol utilization as unique carbon source Esterase activity on long chain satured fatty acids (Tween60) Esterase activity on long chain insatured fatty acids (tryoleine) Production of polysaccarides Salinity tolerance Screening of the 2001 isolates collection for selected metabolic activities Evaluation of the metabolic differences among the basins microflora

Oil utilization  Inoculum preparation in M9 mineral broth with yeast extract as carbon source  Cells wash, and resuspension in mineral medium (NaCl concentration optimum for each strain) with 3‰ crude oil as unique carbon source  Incubation at 28°C and growth revealing with INT (iodoniltetrazolium violet) Almost alll the positive strains were able to grow on catechol as unique carbon source Bannock shows the highest activity in oil degradation The activity is prevalent in the sediments

Lipase-esterase activity on long chain satured fatty acids  Inoculum preparation on rich liquid medium (PCB) with 5% NaCl  Inoculation of minimal solid media with Tween60 and 3/5% NaCl  Incubation 6 days at 30°C  Screening of results (CaCl 2 precipitation) Lipase-esterase activity is highly present among the isolated strains L’Atalante shows the lowest activity for the idrolysis of long chain fatty acids The activity is prevalent at the water/brine interface

Lipase-esterase activity on long chain unsatured fatty acids  Inoculum preparation on rich liquid medium (PCB) with 5% NaCl  Inoculation of minimal solid media with tryolein and 3/5% NaCl  Incubation 6 days at 30°C  Screening of results (CuSO 4 precipitation) Lipase-esterase activity on unsatured fatty acids is very low in all the basins Urania shows the lowest number of active strains The activity is expressed mainly in the water/brine interface, at seawater salinity value

Polysaccarides production  Growth on rich liquid medium (PCB) with 5% NaCl  Precipitation with 1 volume of acetone Half of the strains exhibit production of exopolysaccarides Discovery has the lowest range of polysaccarides production

Antibacterial activity  Growth on rich solid medium (PCA) with 3% NaCl  Killing of cells with chloroform  Overlay with Sarcina lutea culture, incubation at 30°C  Screening of inhibition rings Tested all 94 collection strains: no antibacterial activity found

In the Bannock basin a large amount of the cultivable microflora has interesting metabolic capabilities Discovery shows the lowest metabolic activity

Salt tolerance  Growth in solid media containing different concentrations of NaCl All the strains grow at seawater salinity Few strains do not tolerate absence of NaCl in the growing medium Few strains isolated mostly from Urania and Discovery tolerate >15% NaCl L’Atalante isolates have the lowest values of tolerance

AMO: Anaerobic Methane Oxidation search  Brines  Mud pit samples sample CH 4 Bromodeoxyuridine BrdU On board Immunocapture BrdU-labelled DNA Identification of the actively growing bacteria = methane oxidizing Incubation GC CH 4 oxidation measurement Fluxed with N2 to eliminate endogenous CH 4 DNA extraction

AMO: Anaerobic Methane Oxidation search 30 days of incubation:15°C brines 45°C mud pit CH 4 consumption GC measurement Mud pit brine