Development of a reliable extraction method for the recovery of total genomic DNA from woodchip colonizing biofilm involved in gas biofiltration

[Abstract] This preliminary study focused on a critical step for the characterization of microbial ecosystem involved in biofiltration. Two aspects of nucleic acid recovery were explored: (i) cell dispersion (three methods tested) and (ii) total DNA extraction (four methods tested). The objective is to select the optimal combination of desorption/extraction methods, allowing subsequent molecular investigations to be reliable. Three relevant criteria are used to assess extraction efficiency: DNA amount and purity, and subsequent amplification feasibility

A comparative evaluation of dried activated sludge and mixed dried activated sludge with rice husk silica to remove hydrogen sulfide.

The aim of this study was to investigate the effectiveness of dried activated sludge (DAS) and mixed dried activated sludge with rice husk silica (DAS & RHS) for removal of hydrogen sulfide (H2S). Two laboratory-scale filter columns (packed one litter) were operated. Both systems were operated under different conditions of two parameters, namely different inlet gas concentrations and different inlet flow rates. The DAS & RHS packed filter showed more than 99.96% removal efficiency (RE) with empty bed residence time (EBRT) of 45 to 90 s and 300 mg/L inlet concentration of H2S. However, the RE decreased to 96.87% with the EBRT of 30 s. In the same condition, the DAS packed filter showed 99.37% RE. Nonetheless, the RE was shown to have dropped to 82.09% with the EBRT of 30 s. The maximum elimination capacity (EC) was obtained in the DAS & RHS packed filter up to 52.32 g/m3h, with the RE of 96.87% and H2S mass loading rate of 54 g/m3h. The maximum EC in the DAS packed filter was obtained up to 44.33 g/m3h with the RE of 82.09% and the H2S mass loading rate of 54 g/m3h. After 53 days of operating time and 54 g/m3h of loading rates, the maximum pressure drop reached to 3.0 and 8.0 (mm H2O) for the DAS & RHS packed and DAS packed filters, respectively. Based on the findings of this study, the DAS & RHS could be considered as a more suitable packing material to remove H2S

A comparative study of biodegradation of vinyl acetate by environmental strains

Four Gram-negative strains, E3_2001, EC1_2004, EC3_3502 and EC2_3502, previously isolated from soil samples, were subjected to comparative studies in order to select the best vinyl acetate degrader for waste gas treatment. Comparison of biochemical and physiological tests as well as the results of fatty acids analyses were comparable with the results of 16S rRNA gene sequence analyses. The isolated strains were identified as Pseudomonas putida EC3_2001, Pseudomonas putida EC1_2004, Achromobacter xylosoxidans EC3_3502 and Agrobacterium sp. EC2_3502 strains. Two additional strains, Pseudomonas fluorescens PCM 2123 and Stenotrophomonas malthophilia KB2, were used as controls. All described strains were able to use vinyl acetate as the only source of carbon and energy under aerobic as well as oxygen deficiency conditions. Esterase, alcohol dehydrogenase and aldehyde dehydrogenase were involved in vinyl acetate decomposition under aerobic conditions. Shorter degradation times of vinyl acetate were associated with accumulation of acetic acid, acetaldehyde and ethanol as intermediates in the culture fluids of EC3_2001 and KB2 strains. Complete aerobic degradation of vinyl acetate combined with a low increase in biomass was observed for EC3_2001 and EC1_2004 strains. In conclusion, P. putida EC1_2004 is proposed as the best vinyl acetate degrader for future waste gas treatment in trickle-bed bioreactors

Abatement of styrene waste gas emission by biofilter and biotrickling filter: comparison of packing materials and inoculation procedures

The removal of styrene was studied using 2 biofilters packed with peat and coconut fibre (BF1-P and BF2-C, respectively) and 1 biotrickling filter (BTF) packed with plastic rings. Two inoculation procedures were applied: an enriched culture with strain Pseudomonas putida CECT 324 for biofilters and activated sludge from a municipal wastewater treatment plant for the BTF. Inlet loads (ILs) between 10 and 45 g m-3 h-1 and empty bed residence times (EBRTs) from 30 to 120 s were applied. At inlet concentrations ranging between 200 and 400 mg Nm-3, removal efficiencies between 70 and 95% were obtained in the 3 bioreactors. Maximum elimination capacities (ECs) of 81 and 39 g m-3 h-1 were obtained for the first quarter of the BF1-P and BF2-C, respectively (IL of 173 g m-3 h-1 and EBRT of 60 s in BF1-P; IL of 89 g m-3 h-1 and EBRT of 90 s in BF2-C). A maximum EC of 52 g m-3 h-1 was obtained for the first third of the BTF (IL of 116 g m-3 h-1, EBRT of 45 s). Problems regarding high pressure drop appeared in the peat biofilter, whereas drying episodes occurred in the coconut fibre biofilter. DGGE revealed that the pure culture used for biofilter inoculation was not detected by day 105. Although 2 different inoculation procedures were applied, similar styrene removal at the end of the experiments was observed. The use as inoculum of activated sludge from municipal wastewater treatment plant appears a more feasible option

Membrane Bioreactors for Waste gas Treatment

Producción CientíficaIn the chapter on “Membrane Bioreactors for Waste Gas Treatment” an overview of recent progress in this field is given. In contrast with waste water treatment, membrane systems for waste gas treatment are still in the exploratory stage, although advantages are obvious: in membrane systems the air and aqueous phase are separated, which allows better performance for hydrophobic compounds. The bottleneck, however, is the scaling up of the system. In this chapter the basics of membrane permeation; reactor configuration; results of lab and pilot scale membrane waste gas treatment studies; microbiological aspects and modeling are discussed and future perspectives are presented

Amélioration de la compréhension des mécanismes de rouissage en champs des tiges de chanvre : vers la recherche d’indicateurs pour le développement de biocomposites.

National audienc

Biodétérioration et Entretien des Ouvrages

International audienceLa biodétérioration/biocorrosion/corrosion microbienne est le résultat d’interactions entre le matériau, le milieu extérieur (environnement) et les microorganismes généralement présents sous forme de biofilm. Les mécanismes de biocorrosion sont multifactoriels, complexes et les moyens de lutte contre ce fléau doivent être adaptés au cas par cas. Le développement et l’amélioration de moyens de lutte contre ce fléau ne peuvent donc être menées à bien qu’au fruit d’une collaboration intensive entre les différentes disciplines impliquées : métallurgie, chimie, électrochimie, microbiologie, biochimie...Les techniques d’analyse qui facilitent le suivi de l’évolution du biofilm doivent permettre d’agir au moment opportun pour lutter contre sa formation. De plus, la prédiction comme l’étude des phénomènes liés à la corrosion bactérienne sont importantes non seulement pour mieux appréhender les modifications des surfaces dans ces milieux, mais aussi pour aider les industriels dans le choix des matériaux dont l’enjeu économique est crucial

Amélioration de la compréhension des mécanismes de rouissage en champs des tiges de chanvre : vers la recherche d’indicateurs pour le développement de biocomposites.

National audienc

Biodétérioration et Entretien des Ouvrages

International audienceLa biodétérioration/biocorrosion/corrosion microbienne est le résultat d’interactions entre le matériau, le milieu extérieur (environnement) et les microorganismes généralement présents sous forme de biofilm. Les mécanismes de biocorrosion sont multifactoriels, complexes et les moyens de lutte contre ce fléau doivent être adaptés au cas par cas. Le développement et l’amélioration de moyens de lutte contre ce fléau ne peuvent donc être menées à bien qu’au fruit d’une collaboration intensive entre les différentes disciplines impliquées : métallurgie, chimie, électrochimie, microbiologie, biochimie...Les techniques d’analyse qui facilitent le suivi de l’évolution du biofilm doivent permettre d’agir au moment opportun pour lutter contre sa formation. De plus, la prédiction comme l’étude des phénomènes liés à la corrosion bactérienne sont importantes non seulement pour mieux appréhender les modifications des surfaces dans ces milieux, mais aussi pour aider les industriels dans le choix des matériaux dont l’enjeu économique est crucial