Anaerobic degradation of phenylacetic acid by mixed and pure cultures

1989 ◽  
Vol 31 (1) ◽  
Author(s):  
T. Sembiring ◽  
J. Winter
2013 ◽  
Vol 807-809 ◽  
pp. 1026-1030 ◽  
Author(s):  
Chun Yuan Wu ◽  
Jin Kun Liu ◽  
Shan Shan Chen ◽  
Xiao Deng ◽  
Qin Fen Li

The aim of this paper is to isolate pure cultures that are capable of degrading paraquat (PQ) anaerobically with humic substances (humus) as the sole electron acceptor. Three facultative anaerobic bacteria (PQ-1, PQ-2, and PQ-3) were successively isolated from vegetable soil in Sanya city, China, via enrichment procedure with PQ and anthraquinone-2,6-disulphonate (AQDS) under anaerobic conditions. Batch experiments were conducted to investigate isolates PQ anaerobic degradation activity. Results showed that three strains were all capable of degrading PQ directly with AQDS as the sole electron acceptor (18.6% removal within 48h), and the microbial process might be AQDS dependent. The addition of low molecular weight organic substrate, such as sucrose, could enhance the anaerobic degradation of PQ from 18.6% to 34.2%, and the degradation rate reached 100% after 5-day incubation. This study was the first paper reporting that pure cultures have the ability to anaerobically degrade PQ with AQDS as the sole electron acceptor.


2016 ◽  
Vol 26 (1-3) ◽  
pp. 92-118 ◽  
Author(s):  
Rainer U. Meckenstock ◽  
Matthias Boll ◽  
Housna Mouttaki ◽  
Janina S. Koelschbach ◽  
Paola Cunha Tarouco ◽  
...  

Aromatic hydrocarbons such as benzene and polycyclic aromatic hydrocarbons (PAHs) are very slowly degraded without molecular oxygen. Here, we review the recent advances in the elucidation of the first known degradation pathways of these environmental hazards. Anaerobic degradation of benzene and PAHs has been successfully documented in the environment by metabolite analysis, compound-specific isotope analysis and microcosm studies. Subsequently, also enrichments and pure cultures were obtained that anaerobically degrade benzene, naphthalene or methylnaphthalene, and even phenanthrene, the largest PAH currently known to be degradable under anoxic conditions. Although such cultures grow very slowly, with doubling times of around 2 weeks, and produce only very little biomass in batch cultures, successful proteogenomic, transcriptomic and biochemical studies revealed novel degradation pathways with exciting biochemical reactions such as for example the carboxylation of naphthalene or the ATP-independent reduction of naphthoyl-coenzyme A. The elucidation of the first anaerobic degradation pathways of naphthalene and methylnaphthalene at the genetic and biochemical level now opens the door to studying the anaerobic metabolism and ecology of anaerobic PAH degraders. This will contribute to assessing the fate of one of the most important contaminant classes in anoxic sediments and aquifers.


1991 ◽  
Vol 157 (1) ◽  
Author(s):  
RietJ. Schocher ◽  
Birgit Seyfried ◽  
Francisco Vazquez ◽  
Josef Zeyer

2016 ◽  
Vol 167 (2) ◽  
pp. 98-104
Author(s):  
Bastien Cochard ◽  
François Lefort

A case of sooty bark disease and Cytospora poplar canker in the Canton of Geneva In summer 2014, a case of sooty bark disease caused by Cryptostroma corticale on an individual field maple (Acer campestre) and two cases of poplar canker due to Cytospora chrysosperma on Populus x euramericana were identified genetically for the first time on the territory of the Canton of Geneva. In both cases, the trees presented signs of very advanced dieback, accompanied by specific symptoms such as bark peeling and sooty plaques for the maple, and loose twisted bark layers and black colouring of the wood in structural branches of the poplars. Sampling was carried out in the symptomatic areas and components of the fungal flora were isolated in pure cultures in order to identify any pathogenic fungi. The molecular analysis of the rDNA internal transcribed spacer (ITS) sequences made it possible to identify precisely all pure isolates obtained. The results showed a majority presence of C. corticale in the maple tree, and of C. chrysosperma in the two poplars. Both these fungi are little known in Switzerland and Europe, and their presence is maybe associated with changes in the climate.


Author(s):  
A.M. Tsitsiashvili ◽  
A.M. Panin ◽  
Ye.N. Nikolayeva ◽  
A.A. Arutyunyan ◽  
M.S. Podporin ◽  
...  

The aim of the study was to evaluate the effectiveness of antibiotic chemotherapy regimens and the dynamics of the nature of microbial associations of the operating area at the surgical stages of treatment of patients using dental implants in conditions of limited bone tissue. The study involved 37 patients (17 m and 20 w, from 32 to 68 years). According to the tactics of the treatment and the type of antibacterial effect, the patients were divided into 3 groups. Per os was prescribed antibiotics as a step therapy: amoxicillin (flemoxin 500 mg 1 tablet 2 per day for 7 days) and amoxicillin / clavulanate (flemoclav 625 mg 1 table 2 per day 7 days), doxycycline (unidox 100 mg 1 table 1 per day 5 days). The 1st group of patients (n1=12; 31.9%) — a multi-stage approach (MA), where the 1st operation is bone grafting (BG) (Flemoxin 500 mg), after 6—9 months, the 2nd dental implantation (DI) (flemoklav 625 mg), after 3—6 months the 3rd — installation of gingival formers (GF) (unidox 100 mg). The 2nd group of patients (n2=14; 36.2%) — a one-stage approach (OA), where the 1st operation is BG with simultaneous DI (flemoxin 500 mg), after 6—9 months — the 2nd — installation of GF (flemoklav 625 mg). 3rd group — narrow/short implants (N/S) without BG were installed (n3=11; 31.9%). The 1st operation — DI (Flemoxin 500 mg), the 2nd — installation of GF (Flemoklav 625 mg). A bacteriological study with the identification of pure cultures of bacteria and determination of sensitivity to antibacterial drugs was performed for all patients before treatment and in dynamics. In MA, there was a suppression of the growth of certain types of bacteria and an increase in the number of species resistant to this antibiotic. In the framework of the OA, when prescribing antibiotics, the results were comparable. With N/S implants, growth inhibition of a number of species present at the beginning of treatment was noted. In multi-stage operations, we consider it reasonable to use beta-lactamase-protected drugs, or drugs of another group that include representatives of parodontopathogenic species and potential carriers of multiple resistance genes in their spectrum of action.


1993 ◽  
Vol 27 (3-4) ◽  
pp. 267-270 ◽  
Author(s):  
M. T. Augoustinos ◽  
N. A. Grabow ◽  
B. Genthe ◽  
R. Kfir

A fluorogenic β-glucuronidase assay comprising membrane filtration followed by selective enumeration on m-FC agar at 44.5°C and further confirmation using tlie 4-metliylumbelliferyl-β-D-glucuronide (MUG) containing medium was evaluated for the detection of Escherichia coli in water. A total of 200 typical blue and non-typical blue colonies were isolated from sea and fresh water samples using initial selective enumeration on m-FC agar. Pure cultures of the selected colonies were further tested using the MUG assay and identified using the API 20E method. Of the colonies tested which were shown to be positive using the MUG assay 99.4% were Escherichia coli. The results of this study indicate the combination of the m-FC method followed by the MUG assay to be highly efficient for the selection and confirmation of E. coli from a wide range of environmental waters.


1999 ◽  
Vol 39 (1) ◽  
pp. 21-29 ◽  
Author(s):  
M. C. Tomei ◽  
C. Levantesi ◽  
S. Rossetti ◽  
V. Tandoi
Keyword(s):  

1996 ◽  
Vol 34 (5-6) ◽  
pp. 309-316 ◽  
Author(s):  
X. S. Jia ◽  
Herbert H. P. Fang ◽  
H. Furumai

Changes of surface charge and extracellular polymer (ECP) content were investigated in batch experiments for three anaerobic sludges, each of which had been enriched at 35°C and pH 639-7.3 for more than 40 batches using propionate, butyrate and glucose, individually, as the sole substrate. Results showed that both ECP and the negative surface charge were dependent on the growth phase of microorganisms. They increased at the beginning of all batches when the microorganisms were in the prolific-growth phase, having high substrate concentration and food-to-microorganisms ratio. Both later gradually returned to their initial levels when the microorganisms were in the declined-growth phase, as the substrate became depleted. The negative surface charge increased linearly with the total-ECP content in all series with slopes of 0.0187, 0.0212 and 0.0157 meq/mg-total-ECP for sludge degrading propionate, butyrate and glucose, respectively. The change of surface charge for the first two sludges was mainly due to the increase of proteinaceous fraction of ECP; but, for glucose-degrading sludge, that could be due to the increases of both proteinaceous and carbohydrate fractions of ECP. The negative-charged nature of anaerobic sludge implies that cations should be able to promote granulation of anaerobic sludge.


Sign in / Sign up

Export Citation Format

Share Document