Given the increased 3-PBA use around the world and its prevalent human exposure, effective techniques for disposal of the pollutant are critically needed. Microorganisms are not only cost- effective but also show good detoxification efficiency with contaminates and provide an environmentally friendly solution to the problem of3-PBA pollution . Unfortunately, attempts to isolate microorganisms in pure culture able to mineralize 3-PBA have usually failed, primarily due to the reason that this chemical is a recalcitrant substrate . It has been suggested that the accumulated 3-PBA, which has antimicrobial property, prevents the proliferation of pyrethroid-degrading microorganisms [22,32]. With the aim of obtaining efficient degradative microorganisms, in the last few years our laboratory has screened a range of contaminated soils for 3-PBA degradation activity. A bacterial strain, designated DG-02, was successfully isolated from the soil with a high efficiency in degrading 3-PBA. 16S rRNA gene sequencing and the physio-biochemical characteristics strongly suggested that strain DG-02 belongs to the Bacillus genus. As far as we know, there is no any information concerning the 3-PBA degradationby bacterial strains belonging to the Bacillus genus. Although Bacillus bacteria have been found to degrade a wide range of different xenobiotic aromatic compounds, including thiophanate-methyl , cypermethrin , chlorpyrifos , and 4-chloro-2-nitrophenol , our current results firstly describe the biodegradation of3-PBA by this genus bacteria and definitely expand this list. It is thus becoming evident that Bacillussp. is ubiquitous in the environment and possesses broad catabolic capabilities.
Catechols are formed during biodegradation of a variety of aromatic compounds by aerobic microorganisms 16 . C12D found in Psuedomonas sp. was the first enzyme proved to be a dioxygenase that catalyses the conversion of catechol to cis-cis muconic acid 37 . Under aerobic conditions BTEX compounds are initiated for ring cleavage by the introduction of hydroxyl groups that are initially catalyzed by oxygenases, hence it typically proceeds through catechol intermediates 38 . Aromatic compounds undergo degradation through oxygenetic ring fission by C12D (EC 184.108.40.206). It catalyzes the intradiol cleavage of the aromatic ring at 1,2 (ortho) position of catechol that leads to production of cis-cis muconic acid. In this study of enzymatic activity, ortho pathway for degradationof BTEX were identified and the activity of the enzyme C12D was quantified. The environmental conditions that affect the activity of C12D from Bacillus pumilus were determined in cell free extract. According to the results obtained, pH affected the activity of the enzyme so did the temperature and metal ions. In our findings the SDS PAGE releaved a band at 35 kDa. Similarly the subunit molecular weight of C12D was estimated to be 31,558 and 34,500 Da from Rhodochrous NCIMB 13259 39 and Stenotrophomonas maltophilia strain KB2 40 , receptively. Three bands were observed in Zymography which were in agreement with the findings of three isoenzymes of C12D that have been reported from Pseudomonas arvilla C-1, which were formed by the combination of two nonidentical subunits 41 . Since only the presence of the isoforms were studied, further studies on their kinetic properties and cellular distributions have to be investigated to make clear the physiological significance of these isoforms. In conclusion C12D, from Bacillus pumilus MVSV3 could serve as a better tool in degrading BTEX to catechol and production of muconic acid. The wide spectrum of the enzyme over temperature and pH range and on different metal ions may be further used for efficient degradationof BTEX.
another study, Mycobacterium sp. Strain RJGII-135 showed 25 % co-metabolic mineralization of BaP in soil after 180 days (8). In a different study, Mycobacterium sp. strain RJGII-135 demonstrated about 40% degradationof BaP after 32 days (25). Co-metabolic degradation (41%) of BaP was also demonstrated by Burkholderia cepacia strains after 56 days (15). Some of the other studies involved use of bacterial consortium derived from soil which co-metabolically mineralizes BaP to greater than 95% in 150 days and 33-65% with in two weeks when provided with a complex hydrocarbon co substrate such as crude oil and diesel fuel separately in soil (17, 19). In a recent study, Bacillus subtilis- tgr3 isolated from PAH contaminated soil was able to transform 55% and 65% of BaP with in 48 h and 72 h at 30 o C when grown on minimal media supplemented with sodium citrate (13). However, during incubation, tgr-3 showed only 10 2 fold enhancement in cell number after 48 hours after that it declined drastically becoming non-viable with in 96 hours.
Feigel and Knackmuss (15) have reported degradationof 4-aminobenzene sulphonic acid in a co-metabolism by two species of bacteria. Hydrogenophaga deaminated 4- aminobenzene sulphonic acidby regioselective 3,4- dioxygenation. The major part of the metabolite was catechol 4-sulfonate which was further metabolized by Agrobacterium radiobacter. Nortemann et al. (33) showed that Pseudomonas sp. BN6 could oxidize 1- and 2-naphthalene sulfonate, 1- hydroxynaphthalene 2-sulfonate, 2,6-naphthalene disullfonate and all monosulfonated naphthalene 2-sulfonates which carry one or two substitutents in the positions 4-, 5-, 6-, 7- or 8- of the naphthalene ring system with the exception of 4- or 5- amino and 4-hydroxynaphthalene 2-sulfonates. These compounds were converted to the corresponding salicylates. However the strain BN6 did not oxidize substituted naphthalene 1-sulfonates, naphthalene 3-sulfonates and naphthalene disulfonates. 5-Hydroxyquinoline 2-carboxylic acid was obtained as an end product from the degradationof 5- Amino naphthalene 2-sulfonic acidby Pseudomonas sp. (32). The formation of 5-hydroxyquinoline 2-carboxylate prevented NADH regeneration and further oxidation of 5-amino naphthalene 2-sulfonic acid was limited by the internal NADH pool. Moraxella sp. isolated from industrial sewage plant could degrade Naphthalene 2, 6 and Naphthalene 1, 6 disulfonic acids (48). Regioselective 1,2-dioxygenation caused desulfonation of the compound resulting in accumulation of 5- sulfosalicylic acid which also could be used as the sole carbon source. 5-Sulfosalicylic acid grown cells exhibited high gentisate 1,2-dioxygenase activity. Bacteria degrading amino hydroxy naphthalene sulphonic acids have been isolated from river Elbe by Nortemann et al. (31). The complete degradationof 6-aminonaphthalene 2-sulfonic acid was carried out by a mutualistic interaction of two Pseudomonas strains. Strain BN6 effected the initial conversion of the compound into 5-
filtered with glass wool) were incubated in the dark (20.0°C ± 0.6) under aerobic and anaerobic con- ditions, during 16 days. On sampling days (0, 1, 2, 3, 4, 5, 6, 7, 10, 12, 14 and 16), the concentrations of tannic acid were determined by colorimetric method (Bianchini Jr. & Toledo, 1981) and the dissolved organic carbon by high combustion analysis with a SHIMADZU TOC-5000A analyzer. Total phosphorus (Mackereth et al., 1978), nitrate (modify from Mackereth et al., 1978) and nitrite (Strickland & Parsons, 1960) were also determined on the incubated water samples. The degradation rates were estimated through the losses of tannic acid and organic carbon occurred during the incubation period. Oxygen uptake evaluation was also estimated (in triplicate) using a set of solutions, there was 20.8 mg.L –1 of tannic acid. These solutions
James Watt (Greenock, Escócia, 19 de Janeiro de 1736 — Heathfield Hall, Inglaterra, 25 de Agosto de 1819) foi um matemático e engenheiro escocês e em sua homenagem, devido a suas contribuições científicas, a unidade de potência do "International System of Units" (SI) recebeu o seu nome.
temperature, according to the following standards: PN-76/H- 04601, PN-78/H04610, PN EN ISO 16151. The principle of the method consisted in subjecting the samples of M g-Li alloys to the effect of a solution prepared in a laboratory. The immersion test was conducted in 5% aqueous solution of HCl. To prepare this solution, analytically pure chemical reagents and redistilled water were used. The duration of individual measurement cycles was 6 h, 24 h, 48 h, 72 h and 144 h.
The inhibition of MT degradation in the presence of Fe (III), observed in the results in Table 4 is important, given its common presence in the aquatic environment, which was also investigated by Homklin et al. (2011) in biotransformation trials. According to these authors, MT and its degradation products with androgenic activity can potentially accumulate in sediments of fish farming ponds in the presence of iron (III), due to inhibition of microbial activity, an effect also observed in the presence of excess nitrate. In aerobic conditions and in conditions with the presence of sulfate, there is intense microbial activity that dramatically decreases the amount of MT in the sediment. This means that the presence of Fe (III) can stabilize the molecule of MT in sediment, and it can keep its androgenic activity, highlighting the importance of processes for remediation or degradationof MT in fish tanks.
Foram estudados três corantes ácidos que representam três classes químicas distintas: triarilmetanos, xantenos e azos. Suas principais características são mostradas na Tabela 1. Além disso, o azul brilhante (Acid Blue 9) tem sido associado a efeitos mutagênicos e bioacumu- lação, a eritrosina (Acid Red 18) a tumores cancerígenos e a tartrazina (Acid Yellow 23) a reações alérgicas. 5–8
Kindoli et al., reported that, the B. subtilis W42, B. subtilis SKE 12, B. subtilis K21, and B. subtilis H27 inhibited most indicators such as some LAB, B. thuringiensis, S. carnosum, Enterococcus faecalis (ATCC 29212)and S. epidermis including B. cereus and L.monocytogenes, the two most important food pathogens, but not Gram-negative bacteria. B. subtilis W42 was the most inhibiting as it inhibited 12 out of 20 indicators tested.Sharma et al., claimed that, the culture supernatant ofBacillus subtilisR75 expressed strong inhibition against many microorganisms/pathogens that cause serious food spoilage, viz. L. monocytogenes, L. plantarum, S. aureus, B. subtilis, C. perfringens, B. cereus, E. coli and L. mesenteroides and wide zones of clearance made by crude bacteriocin, ranging up to 5 mm, were observed on the petri dishes, containing indicator bacteria in well diffusion assay. Bacteriocin from Bacillus subtilisR75 has been found capable of controlling Listeriosis, caused by L. monocytogensin the food items stored even at low temperature in the refrigerator, leading to many deaths throughout the world and thus can meet the serious challenge of controlling the spoilage of refrigerated food. Moreover, this bacteriocin is presumed completely safe for human consumption because of its origin from a food grade bacterium.
The co-feeding fermentation based on a mixture of glucose and beet molasses in this study showed the positive effect of beet molasses on lactic acid production. The best result was from the fermentation medium that contained 10% (w/w) sugars from beet molasses. Since the total sugar in this experiment was 250 g/L and the beet molasses contains 47% (w/v) sugars and 0.5% (w/v) nitrogen source, there was only 0.27 g/L nitrogen source in the medium of the best co-feeding method. Under such a low nitrogen condition, nitrogen source from beet molasses would have a slight effect on lactic acid production as a role of nutrient. However, it would have an obviously positive effect as an osmoprotectant considering that half of its nitrogen source was betaine. Thus, beet molasses not only provided cheap carbon source for the fermentation, but also provided osmotic protection due to the betaine in it.
400 nm), com cinética inicial menos favorável, permite a obtenção de resultados comparáveis, para tempos de reação algo maiores (10 min). Adicionalmente, estudos paralelos demonstraram a inexistência de diferenças significativas quando o sistema foto-Fenton (UV-A) é operado com ou sem oxigenação (Figura 3). Estes dois resultados se revestem de grande importância, uma vez que permi- tem reduzir de maneira significativa o custo operacional do sistema. Apesar da molécula de benzeno ser bastante resistente aos trata- mentos convencionais, principalmente em razão da estabilidade que o efeito de ressonância lhe confere, a elevada eficiência de degrada- ção do sistema foto-Fenton foi demonstrada neste trabalho, mesmo nas condições brandas representadas pelo sistema não-oxigenado e assistido por radiação UV-A. Em razão destes resultados promisso- res, a degradação de BTXs foi estudada em sistemas foto-Fenton, operados com radiação UV-A e na ausência de oxigenação.
The N-terminal amino acid sequencing showed the removal of the N-terminal signal peptide from AspSP. We thus deemed more convenient to express the recombinant L- asparaginase protein in one compartment and avoid leakage to extracellular medium. Accordingly, we constructed L-asparaginase without the signal peptide sequence (AspMP). Amino acid sequencing (AENLPNIVILA) showed that the N-terminal methionine was removed from the AspMP. A common type of co-/post-translational modification of proteins synthesized in prokaryotic cells is modification at their N-termini. Methionine aminopeptidase catalyzed cleavage of initiator methionine is usually directed by the penultimate amino acid residues with the smallest side chain radii of gyration (glycine, alanine, serine, threonine, proline, valine, and cysteine) (Lowther and Matthews 2000). This substrate preference of methionine aminopeptidases is opposite to the “N-end rule” for protein degradation, in which methionine aminopeptidase will not remove an N-terminal methionine if a “destabilizing” amino acid will be exposed (Varshavsky 2008). As the clinical use of L-asparaginases II can be limited by its in vivo inactivation by proteolysis (Guo et al 2000), it is thus expected that the recombinant AspMP here described would have favorable in vivo half-life since the N- terminal amino acid residue after methionine removal is alanine – a stabilizing amino acid residue. Moreover, the N-terminal amino acid sequence of AspMP is identical to recombinant AspSP protein having the signal peptide removed. In addition, as the main sources of L- asparaginases II commercially available are produced by non-recombinant fermentation of E. coli and E. chrysanthemi and have thus their signal peptide sequence removed, the construct here described for AspMP may represent an attractive alternative for large scale production of E. carotovora L-asparaginases II. It should also be pointed out that the N-terminal amino acid sequencing showed that AspMP was separated from its E. coli counterpart, which has an important bearing on E. carotovora L-asparaginases II preparation since these two enzymes have distinct immunological specificities and provide alternative therapy if a patient develops hypersensitivity to either L-asparaginases II (Bascomb and Bettelheim 1976).