Microbes for Archaeological Wood Conservation

This project focuses on innovative biological methods of extraction for the preservation of waterlogged wood suffering from salt precipitation and acidification. The principal investigator and her team proposed to exploit biomineralization capacities of some bacteria for anticipating the extraction of iron and sulfur compounds when wood is still wet. A comprehensive assessment of the extraction performances achieved on wood objects from lake and marine environments will allow a versatile extraction method to be proposed to end-users

Biotechnologies as catalysts for driving net zero

R&D impact delivered by this work extends to policy development and to the benefits derived from delivering circularity, green growth and reducing carbon emissions by anaerobic digestion that (1) recovers a variety of organic wastes and low value biomass and (2) produces bioenergy and fertiliser. Other biotechnologies being developed can recover resources for the production of fuels (CH4, H2 and NH3), chemicals e.g. volatile fatty acids, biopolymers e.g. polyhydroxyalkanoates and single-cell proteins that can be used for animal feed. Biotechnologies delivering solutions for Power to X, for energy storage and for the capture and use of carbon have also been a focus of our research. Monitoring and control methodologies for the biotechnologies have been developed, including the use of analytical technologies such as FTNIR, GC-IMS and qPCR. Work continues on the valorisation of digestates as microbial and algae growth media, and the recovery of nutrients (NPK). Evaluations of the fate of polymers in the environment, their biochemical recycling and the production of biostimulants for soil and crop improvements, nitrogen fixing and emissions’ reduction are all in progress. Technologies are currently across the TRL 3-6 range and require further R&D to progress them to commercialisation. Deploying industrial biotechnologies is essential to act as sustainable catalysts for change and for delivering net zero, circular economy and green growth. Biotechnologies can impact beneficially on the sustainability of cities and benefit their relationship and integration with surrounding rural areas

Building efficient biocathodes with Acidithiobacillus ferrooxidans for the high current generation

International audienceThe development of biocathodes is highly fascinating in microbial electrochemical technologies research. In this study, iron-oxidizing bacterium Acidithiobacillus ferrooxidans-based biocathodes were developed under the con-stant polarization of the electrochemical reactors at -0.2 V vs. Ag/AgCl with a pH of 2. On the 15th day of the 21-day batch experiment, A. ferrooxidans-based biocathode produced a maximum current density of-38.61 +/- 13.16 A m(-2) when the reactors were supplemented with 125 mM Fe2+ ions as an electron donor and 9 mM citrate as an iron chelator to buffer the iron-rich medium. Oxidation of Fe2+ to Fe3+ by A. ferrooxidans and its electrochemical regeneration at the cathode were mainly responsible for the high current generation. Furthermore, in the presence of iron, A. ferrooxidans develop a multi-layer biofilm on the cathode surface, which could potentially perform an indirect electron transfer mechanism

Functional assessment of subtilosin A against <em>Aeromonas</em> spp. causing gastroenteritis and hemorrhagic septicaemia

27-32Anti-Aeromonas and cell membrane lytic bacteriocin substance, subtilosin A producing Bacillus subtilis VT03 was explored. Strain VT03 was isolated from freshwater fish (Tilapia) intestine and screened for its antimicrobial activity against four pathogenic strains of Aeromonas spp. causing gastroenteritis and hemorrhagic septicaemia. Isolate (VT03) was identified showing inhibition in agar spot assay. The strain VT03 was the one exhibiting strong inhibition and identified as Bacillus subtilis using 16S rRNA sequencing. Cell free supernatant (CFS) of the strain VT03 was active against pathogenic strains of Aeromonas spp, subsequently CFS was partially purified and designated as PPB-VT03 showing inhibition against A. hydrophila ATCC 49140. PPB-VT03 completely lost its activity upon treating with proteinase K revealing that the defense molecule could be proteinaceous in nature. Based on polymerase chain reaction (PCR), functional gene coding for subtilosin A (sboA) was found to be present whereas subtilin (spaS) was absent. The role of partially purified bacteriocin of isolate VT03 (PPB-VT03) through FTIR and SEM analysis revealed the activity of cell lysis. The study demonstrated the potential use of subtilosin A producing Bacillus subtilis as a potent source for antibacterial peptide

Structural characterization, functional and biological activities of an exopolysaccharide produced by probiotic Bacillus licheniformis AG-06 from Indian polyherbal fermented traditional medicine

International audienceAn exopolysaccharide (EPS) was purified from the probiotic bacterium Bacillus licheniformis AG-06 isolated from the polyherbal fermented traditional medicine (Ashwagandharishta) of Indian Ayurveda. High-performance liquid chromatography (HPLC) based compositional analysis exhibits the heteropolymeric nature of the EPS consisting of galactose, rhamnose, xylose, mannose, and glucose, as the monomeric units. Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic analyses confirm the presence of typical carbohydrate polymer functional groups and structural units, respectively. The purified EPS demonstrates the web-like fibrous and porous nature in scanning electron microscopic and atomic force microscopic studies. The purified EPS had shown 71.83% and 67.79% of flocculation and emulsification activities, respectively. Antioxidant activity was evaluated against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), nitric oxide, and superoxide free radicals and the scavenging actions were increased in a dose-dependent manner. Moreover, the purified EPS exhibits a significant cytotoxic activity against the human lung carcinoma cells (A549), which strongly suggests the anticancer potential of the EPS derived from B. licheniformis AG-06

Manganese-II oxidation and Copper-II resistance in endospore forming Firmicutes isolated from uncontaminated environmental sites

The accumulation of metals in natural environments is a growing concern of modern societies since they constitute persistent, non-degradable contaminants. Microorganisms are involved in redox processes and participate to the biogeochemical cycling of metals. Some endospore-forming Firmicutes (EFF) are known to oxidize and reduce specific metals and have been isolated from metal-contaminated sites. However, whether EFF isolated from uncontaminated sites have the same capabilities has not been thoroughly studied. In this study, we measured manganese oxidation and copper resistance of aerobic EFF from uncontaminated sites. For the purposes of this study we have sampled 22 natural habitats and isolated 109 EFF strains. Manganese oxidation and copper resistance were evaluated by growth tests as well as by molecular biology. Overall, manganese oxidation and tolerance to over 2 mM copper was widespread among the isolates (more than 44% of the isolates exhibited Mn (II)-oxidizing activity through visible Birnessite formation and 9.1% tolerate over 2 mM copper). The co-occurrence of these properties in the isolates was also studied. Manganese oxidation and tolerance to copper were not consistently found among phylogenetically related isolates. Additional analysis correlating the physicochemical parameters measured on the sampling sites and the metabolic capabilities of the isolates showed a positive correlation between in situ alkaline conditions and the ability of the strains to perform manganese oxidation. Likewise, a negative correlation between temperature in the habitat and copper tolerance of the strains was observed. Our results lead to the conclusion that metal tolerance is a wide spread phenomenon in unrelated aerobic EFF from natural uncontaminated environments

Assessing the versatility of bioextraction to preserve waterlogged wood

An innovative bio method was investigated to extract harmful iron and sulfur species from waterlogged wood samples. The method was compared with a chemical treatment. Both approaches were applied on lacustrine and marine samples, from different wood genera, to evaluate the versatility of the proposed bio method. Non-invasive and non-destructive methods were carried out to investigate both bio-based and chemical treatments. The result was that some wood genera were more affected by the bio approach, with a clear distinction between lacustrine beech and pine against oak and lime wood species. The chemical approach showed potential harm for the wooden structure, with acidic pH values and an increase of maximum water content, both implying degradation of the wood structure. In terms of extraction, no iron or sulfur products were detected by Raman spectroscopy on biologically treated samples, in agreement with extraction rates calculated. It was also suggested that iron bonded to wood was extracted with the chemical approach, and calcium content affected by both approaches

Production and Characterization of a Novel Exopolysaccharide from Ramlibacter tataouinensis

International audienceThe current study examines the desiccation-resistant Ramlibacter tataouinensis TTB310T as a model organism for the production of novel exopolysaccharides and their structural features. This bacterium is able to produce dividing forms of cysts which synthesize cell-bound exopolysaccharide. Initial experiments were conducted on the enrichment of cyst biomass for exopolysaccharide production under batch-fed conditions in a pilot-scale bioreactor, with lactate as the source of carbon and energy. The optimized medium produced significant quantities of exopolysaccharide in a single growth phase, since the production of exopolysaccharide took place during the division of the cysts. The exopolysaccharide layer was extracted from the cysts using a modified trichloroacetic acid method. The biochemical characterization of purified exopolysaccharide was performed by gas chromatography, ultrahigh-resolution mass spectrometry, nuclear magnetic resonance, and Fourier-transform infrared spectrometry. The repeating unit of exopolysaccharide was a decasaccharide consisting of ribose, glucose, rhamnose, galactose, mannose, and glucuronic acid with the ratio 3:2:2:1:1:1, and additional substituents such as acetyl, succinyl, and methyl moieties were also observed as a part of the exopolysaccharide structure. This study contributes to a fundamental understanding of the novel structural features of exopolysaccharide from a dividing form of cysts, and, further, results can be used to study its rheological properties for various industrial applications