•Allochthonous bioaugmentation, in contrast to biostimulation, was ineffective.•The applied consortia/strains were not capable to colonize the sediment.•The indigenous microbiome was very effective ...when supplemented with nutrients.•The reasons for the ineffectiveness of bioaugementation have been identified.
Oil-polluted sediment bioremediation depends on both physicochemical and biological parameters, but the effect of the latter cannot be evaluated without the optimization of the former. We aimed in optimizing the physicochemical parameters related to biodegradation by applying an ex-situ landfarming set-up combined with biostimulation to oil-polluted sediment, in order to determine the added effect of bioaugmentation by four allochthonous oil-degrading bacterial consortia in relation to the degradation efficiency of the indigenous community. We monitored hydrocarbon degradation, sediment ecotoxicity and hydrolytic activity, bacterial population sizes and bacterial community dynamics, characterizing the dominant taxa through time and at each treatment. We observed no significant differences in total degradation, but increased ecotoxicity between the different treatments receiving both biostimulation and bioaugmentation and the biostimulated-only control. Moreover, the added allochthonous bacteria quickly perished and were rarely detected, their addition inducing minimal shifts in community structure although it altered the distribution of the residual hydrocarbons in two treatments. Therefore, we concluded that biodegradation was mostly performed by the autochthonous populations while bioaugmentation, in contrast to biostimulation, did not enhance the remediation process. Our results indicate that when environmental conditions are optimized, the indigenous microbiome at a polluted site will likely outperform any allochthonous consortium.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A preliminary checklist of macromycetes has been previously published with reference to six governorates located in northern Tunisia. This paper provides an updated version of the inventory of ...macromycetes in Tunisia, which includes 268 species, of which seven are worldwide recognized as rare. The investigation was carried out from September 2015 to December 2018 in 13 governorates of the Tunisian territory. This updated checklist reports 145 new national species records (139 basidiomycetes and six ascomycetes) belonging to 57 genera and 13 families. Data related to distribution, ecology and preferential hosts of each recorded taxon are also provided.
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BFBNIB, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Within the last decade, checklists of fungi of several countries have been published or updated. Nevertheless, no checklists of macromycetes have hitherto been published for Tunisia (North Africa) ...apart from a mycocoenological study reporting 34 listed species. This work presents a list of macromycetes collected from January 2014 to March 2015 in six governorates of northern Tunisia. One hundred and twenty-three species (117 basidiomycetes and six ascomycetes) belonging to 78 genera and 46 families were recorded.
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BFBNIB, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
To assess esterase profiling of members of Geodermatophilaceae isolated from desert stones and monuments in Tunisia and Egypt. Members of Geodermatophilaceae family isolated from desert stones and ...monuments in Tunisia and Egypt were characterized by partial 16S rRNA sequences. Twenty-five strains were clustered in three dissimilar groups of the genera Geodermatophilus (12 strains), Blastococcus (5 strains) and Modestobacter (3 strains). Isolates were also screened and typed based on major groups of esterase hydrolytic activity. Their esterase patterns were determined and compared to those of ten reference strains belonging to Geodermatophilaceae family. Strains exhibited a diverse and complex pattern of electrophoretic esterase bands, and 31 haplotypes were obtained for the 35 investigated strains. Esterases produced by members of Geodermatophilaceae family have an optimal activity around 40°C and at pH 8. Esterases from Geodermatophilus strains display a high resistance to thermal inactivation and alkaline pH and retaining 30 and 20% of activity after heating for 20 min at 120°C and at pH 12, respectively, and were completely inactivated after 30 min at 120°C. Enzyme activity has been strongly activated in the presence of Ca²⁺and Mg²⁺ ions and moderately by Zn²⁺ and was markedly inhibited by Cu²⁺ and Co²⁺ ions. Geodermatophilaceae isolates share a rich and particular pool of esterase activities that could be directly linked to harsh conditions characterizing their ecological habitat including high level of aridity, temperature, ionic strength and low nutrient availability. Esterase could be considered as enzymatic signature that outlines adaptability of Geodermatophilaceae in arid area.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
To produce high laccase activities from the white-rot fungus Fomes fomentarius. Different culturing methods, viz, cell immobilization on stainless steel sponges and plastic material and solid-state ...fermentation (SSF) using wheat bran as substrate were used for laccase production by the white-rot fungus F. fomentarius. The SSF study expresses the highest laccase activities, nearly to 6400 U l⁻¹ after 13 days of laboratory flasks cultivation. When the wheat bran medium was supplemented with 2 mmol l⁻¹ copper sulfate, laccase activity increased by threefold in comparison to control cultures, reaching 27 864 U l⁻¹. With the medium thus optimized, further experiments were performed in a 3 l fixed-bed bioreactor (working volume 1·5 l) leading to a laccase activity of about 6230 U l⁻¹ on day 13. The results obtained clearly showed the superiority of wheat bran for laccase production over stainless steel sponges and plastic material. Supplementing the wheat bran solid medium with 2 mmol l⁻¹ copper sulfate allowed obtaining high activities at flask scale. The system was scaled to fixed-bed laboratory reactor. The high enzyme production along with the low-cost of the substrate, showed the suitability of the system F. fomentarius- SSF for industrial purposes.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A total of 315 samples of chicken (60), beef (144), minced meat (56), lamb meat (33), merguez (10) and fish (12) were collected from various local outlet stores in the area of “Grand Tunis”, Tunisia ...between 2006 and 2008. Salmonella was recovered from 80 samples with the highest occurrence in chicken (48.3%) followed by beef (29.8%), minced meat (10.7%) and lamb (6.0%). No Salmonella were isolated from 12 fish and 10 merguez samples (typical Tunisian sausages). Nine serovars were identified among the isolates with the predominance of Salmonella Typhimurium (n=25) followed by Salmonella Kentucky (n=14), Salmonella Suberu (n=12) and Salmonella Zanzibar (n=11). Isolated Salmonella were characterized by serotyping, pulsed-field gel electrophoresis (PFGE) analysis, plasmid content and antimicrobial resistance profiling. Sixteen (20.0%) Salmonella isolates displayed resistance to ampicillin (13 isolates), streptomycin (five isolates), cefoperazone (two isolates), furazolodine (two isolates), with seven of these isolates displaying multiple resistance to at least two of these antimicriobal agents. PFGE analysis showed homogenous restriction patterns in each serovar. Compiled serotyping, PFGE analysis, plasmid profiling and antimicrobial resistance data provided additional discrimination.
Un total de 315 échantillons de poulet (60), viande bovine (144), viande hachée (56), viande d’agneau (33), merguez (10) et de poisson (12) ont été recueillis entre 2006 et 2008 de divers magasins de vente locaux de “Grand Tunis”, Tunisie. Des isolats de Salmonella ont été obtenus à partir de 80 échantillons et essentiellement de poulet (48,3%), bœuf (29,8%), viande hachée (10,7%) et d’agneau (6,0%). Aucun isolat n’a été obtenu à partir des échantillons de poisson et de merguez (saucisse tunisien). Neuf sérotypes ont été identifiés parmi les isolats avec une prédominance de Salmonella Typhimurium (n=25) suivie de Salmonelle Kentucky (n=14), Salmonella Suberu (n=12) et Salmonella Zanzibar (n=11). Les isolats de salmonelle ont été caractérisés par sérotypage, électrophorèse en champ pulsé (ECP), contenu plasmidique et de résistance aux antibiotiques. Seize isolats de salmonelle (20,0%) ont montré une résistance à l’ampicilline (13 isolats), streptomycine (cinq isolats), amoxicilline, acide clavulanique (quatre isolats), céfopérazone (deux isolats), furazolodine (deux isolats), avec sept isolats montrant une multirésistance au moins à deux antibiotiques. L’analyse en ECP a montré des profils de restriction homogène pour chacun des sérotypes identifiés. L’analyse combinant les résultats obtenus par sérotypage, ECP, contenu plasmidique et le profil de résistance aux antibiotiques permet une discrimination plus fine des isolats.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In order to define an efficient pre-treatment of Olive Oil Mill Wastewater (OOMW) to overcome major obstacles to biological treatment, various organic and mineral coagulants have been tested. In ...particular, the application of quicklime until a pH around 12 - 12.4 was reached, allowed the reduction of almost 37 % of the initial COD, and approximately 88 % and 71 % of the colour and phenolic content of the waste. Hence, further biological treatments with an adapted aerobic consortium (AC) and a white rot fungus (WRF) strain were improved. The WRF Coriolopsis polyzona was more efficient than AC to reduce colour and polyphenols when the waste was prior diluted or pre-treated; however, it was less effective in COD removal. The combined treatment: lime - AC of OOMW having initial COD of 102 g l
−1
led to the elimination of about 77, 91 and 63 %, of the COD, phenols and colour, respectively. Interestingly, the opposite combination AC - lime permitted better COD, phenols and colour reduction to respectively, 21, 11 and 11% of the initial values. This latter condition is technically recommended since only one step separation was needed and no pH correction was necessary before undergoing aerobic treatment. Moreover, the process would produce a sludge potentially rich in organic matter, and consequently, useful as an agricultural amendment or/and as an additive in animal nutrition.
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During the period from 2006 to 2007, a total of 32 clinical isolates of
Salmonella enterica were isolated from diarrheagenic stool samples and further examined for their susceptibility to various ...antibiotics. Sixteen of the human isolates were from the capital Tunis, 11 were from Sousse, four were from Nabeul and one was from Mahdia, Tunisia. The isolates were serotyped and identified at the National Centre of Enteropathogenic Bacteria, Pasteur Institute, Tunis (Centre National de
Salmonella,
Shigella et
Vibrio – Institut pasteur de Tunis); nine distinct serovars were identified: Enteritidis (
n
=
20), Typhimurium (
n
=
4), Zanzibar (
n
=
2), Manhattan (
n
=
1), Bovismorbificans (
n
=
1), Amsterdam (
n
=
1), Saint Paul (
n
=
1), Kentucky (
n
=
1) and Muenster (
n
=
1). Our results showed that 25
Salmonella isolates (78.1 %) were resistant to antibiotics with 20 isolates (62.5 %) displayed resistance to ampicillin. Isolates sharing
invA gene, as shown by PCR amplification, were further characterized by the techniques of pulsed-field gel electrophoresis (PFGE) using the restriction enzyme
XbaI and plasmid analysis to determine possible genetic relationships among
Salmonella enterica clinical isolates and to assess genetic diversity. Plasmid profiling identified seven plasmid profiles (with 1–5 plasmids) among the isolates; four isolates (
Salmonella Kentucky,
Salmonella Muenster,
Salmonella Bovismorbificans and
Salmonella Zanzibar) did not carry any plasmid. The isolates were differentiated into 10 distinct
XbaI-pulsotypes. Our findings show genetic diversity among the different serovars and cluster analysis of compiled serotyping, PFGE, plasmid profiling and antibiotic resistance data provided additional discrimination.
Pendant la période de 2006 à 2007, 32 souches cliniques de
Salmonella enterica ont été isolées à partir d’échantillons de selles diarrhéiques et ont été ensuite examinées pour leur susceptibilité vis-à-vis de divers antibiotiques. Seize souches ont été isolées dans la capitale Tunis, 11 dans la ville de Sousse, quatre dans la ville de Nabeul et une souche dans la ville de Mahdia, Tunisie. Les souches ont été syrotypées et identifiées par le Centre national de
Salmonella,
Shigella et
Vibrio – institut pasteur de Tunis (National Centre of Enteropathogenic Bacteria, Pasteur Institute, Tunis) ; neuf sérovars ont été identifiés : Enteritidis (
n
=
20), Typhimurium (
n
=
4), Zanzibar (
n
=
2), Manhattan (
n
= 1), Bovismorbificans (
n
=
1), Amsterdam (
n
=
1), Saint Paul (
n
=
1), Kentucky (
n
=
1) et Muenster (
n
=
1). Nos résultats montrent que 25 souches de salmonelles (78,1 %) sont résistantes aux antibiotiques avec 20 souches (62,5 %) montrant une résistance à l’ampicilline. Après amplification par PCR, toutes les souches partageant le gène
invA ont fait l’objet d’une caractérisation par électrophorèse en champ pulsé (ECP) en utilisant l’enzyme de restriction
XbaI et par analyse plasmidique dans le but d’évaluer la diversité génétique et de déterminer des relations génétiques possibles entre les différentes souches de
Salmonella enterica. L’analyse plasmidique a montré sept profils plasmidiques (avec un à cinq plasmides) parmi les souches isolées ; quatre souches (
Salmonella Kentucky,
Salmonella Muenster,
Salmonella Bovismorbificans et
Salmonella Zanzibar) n’ont montré aucun plasmide. Les souches isolées ont été différenciées en dix différents pulsotypes. Nos résultats montrent une diversité génétique parmi les différents sérovars et le regroupement par combinaison du sérotypage, ECP, profils plasmidiques et résistance aux antibiotiques a fourni une discrimination supplémentaire.
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In a previous work was reported the ability of
Pycnoporus coccineus to decolorize olive oil mill wastewaters (OOMW) without an additional carbon source. We studied the composition of the enzymatic ...system involved in the process. The fungus secreted only laccase under the different culture conditions studied even in presence of compounds promoting the production of peroxidases. The highest laccase levels were attained in Cu
2+–ethanol medium (100,000
U/l after 45 incubation-days). A single isoenzyme was purified with a yield of 79%. This laccase is a glycoprotein (8% N-linked carbohydrate) with a molecular mass and pI of 61.5
kDa and 3.7, respectively. The highest oxidation rate was obtained around pH 3.5 for ABTS and DMP and the highest DMP oxidation at 60
°C. The enzyme was stable at pH 7 at room temperature and showed a half-life of 8 and 2
h at 50 and 60
°C, respectively. The treatment of OOMW with the laccase showed similar results to those reported with the fungus indicating that laccase plays an important role in the degradative process. The high levels of laccase secreted by
P. coccineus and its stability suggest that it could be a useful tool for this and other environmental applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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