Assessment of biodegradation kinetics and mass transfer aspects in attached growth bioreactor for effective treatment of brilliant green dye from wastewater.

In this study, Bacillus licheniformis immobilized with low-density polyethylene (LDPE) was employed to degrade Brilliant Green (BG) dye from wastewater in a packed bed bioreactor (PBBR). Bacterial growth and extracellular polymeric substance (EPS) secretion were also assessed under different concentrations of BG dye. The impacts of external mass transfer resistance on BG biodegradation were also evaluated at different flow rates (0.3-1.2 L/h). A new mass transfer correlation [Formula: see text] was proposed to study the mass transfer aspects in attached-growth bioreactor. The intermediates, namely 3- dimethylamino phenol, benzoic acid, 1-4 benzenediol, and acetaldehyde were identified during the biodegradation of BG and, subsequently degradation pathway was proposed. Han - Levenspiel kinetics parameters µmax and Ks were found to be 0.185 per day and 115 mg/L, respectively. The new insight into mass transfer and kinetics support the design of efficiently attached growth bioreactor to treat a wide range of pollutants.

DnsID in MyCompoundID for rapid identification of dansylated amine- and phenol-containing metabolites in LC-MS-based metabolomics.

High-performance chemical isotope labeling (CIL) liquid chromatography-mass spectrometry (LC-MS) is an enabling technology based on rational design of labeling reagents to target a class of metabolites sharing the same functional group (e.g., all the amine-containing metabolites or the amine submetabolome) to provide concomitant improvements in metabolite separation, detection, and quantification. However, identification of labeled metabolites remains to be an analytical challenge. In this work, we describe a library of labeled standards and a search method for metabolite identification in CIL LC-MS. The current library consists of 273 unique metabolites, mainly amines and phenols that are individually labeled by dansylation (Dns). Some of them produced more than one Dns-derivative (isomers or multiple labeled products), resulting in a total of 315 dansyl compounds in the library. These metabolites cover 42 metabolic pathways, allowing the possibility of probing their changes in metabolomics studies. Each labeled metabolite contains three searchable parameters: molecular ion mass, MS/MS spectrum, and retention time (RT). To overcome RT variations caused by experimental conditions used, we have developed a calibration method to normalize RTs of labeled metabolites using a mixture of RT calibrants. A search program, DnsID, has been developed in www.MyCompoundID.org for automated identification of dansyl labeled metabolites in a sample based on matching one or more of the three parameters with those of the library standards. Using human urine as an example, we illustrate the workflow and analytical performance of this method for metabolite identification. This freely accessible resource is expandable by adding more amine and phenol standards in the future. In addition, the same strategy should be applicable for developing other labeled standards libraries to cover different classes of metabolites for comprehensive metabolomics using CIL LC-MS.

Crude soybean hull peroxidase treatment of phenol in synthetic and real wastewater: enzyme economy enhanced by Triton X-100.

Soybean peroxidase (SBP)-catalyzed removal of phenol from wastewater has been demonstrated as a feasible wastewater treatment strategy and a non-ionic surfactant, Triton X-100, has the potential for increasing the enzyme economy of the process. Systematic studies on the enzyme-surfactant system have been lacking as well as demonstration of its applicability to industrial wastewater. This paper addresses those two gaps, the latter based on real wastewater from alkyd resin manufacture. The minimum effective Triton X-100 concentrations for crude SBP-catalyzed phenol conversion (≥95%) over 1-10 mM showed a linear trend. To illustrate translation of such lab results to real-world samples, this data were used to optimize crude SBP needed for phenol conversion over that concentration range. Triton X-100 increases enzyme economy by 10- to 13-fold. This treatment protocol was directly applied to tote-scale (700-1000 L) treatment of alkyd resin wastewater, with phenol ranging from 7 to 28 mM and total organic carbon content of >40 g/L, using a crude SBP extract derived from dry soybean hulls by simple aqueous elution. This extract can be used to remove phenol from a complex industrial wastewater and the process is markedly more efficient in the presence of Triton X-100. The water is thus rendered amenable to conventional biological treatment whilst the hulls could still be used in feed, thus adding further value to the crop.

Phenol biodegradation and simultaneous nitrogen removal using a carbon fiber felt biofilm reactor.

Phenol biodegradation and its effect on the biological nitrogen removal were studied in a biofilm reactor (15 L) packed with carbon fiber felt carriers. Meanwhile, the effects of the effluent internal recirculation ratios (0, 100% and 200%) and the air flow rates (0.42, 0.83, 1.46, 2.08 and 3.33 L/min) on the performance of system were tested. The system exhibited an excellent capacity for simultaneous phenol biodegradation and biological nitrogen removal without effluent internal recirculation when the influent phenol concentration was as high as 1,000 mg/L (organic loading rate of 9.54 kg COD/(m(3) d)) and the ammonia loading rates of 0.20, 0.32 and 0.40 kg NH(4)(+)-N/(m(3) d) respectively). Nitrification process was inhibited at the influent phenol concentration of 1,200-1,300 mg/L with average ammonia removal efficiency of 26.9%. The nitrifiers activity could be recovered in the perfect performance of system for phenol biodegradation. However, denitrification was not affected by the process of phenol biodegradation. In the air flow rates of 1.46-2.08 L/min, the system manifested stable operation for phenol elimination and nitrogen removal. Dissolved oxygen (DO) distributions in carbon fiber felt biofilm descended gradually from the external to the center of the carrier in all air flow rates.

Characteristics of phenol biodegradation in saline solutions by monocultures of Pseudomonas aeruginosa and Pseudomonas pseudomallei.

Phenol is a highly toxic and carcinogenic compound and its biodegradation is very important to meet the environmental regulations. Two bacterial strains capable of utilizing phenol as a sole source of carbon were isolated from the wastewater of a pharmaceutical industry. On the basis of morphological and biochemical characteristics these strains were identified as Pseudomonas aeruginosa and Pseudomonas pseudomallei. Both of these strains were very efficient for phenol degradation. P. pseudomallei degraded phenol at a maximum concentration of 1500 mg L(-1) within seven days with a specific growth rate of 0.013 h(-1) and phenol degradation rate of 13.85 mg L(-1)h(-1). Maximum initial concentration of phenol utilized by P. aeruginosa was 2600 mg L(-1) with 0.016 h(-1) specific growth rate and 26.16 mg L(-1)h(-1) phenol degradation rate. Moreover, the effect of various salts i.e., NaCl, KCl, Na(2)SO(4) and K(2)SO(4) on the growth of these strains and phenol degradation rate (at 1000 mg L(-1)) was studied. In the presence of these salts, P. aeruginosa showed up to 1.53 and 1.34 times faster phenol degradation rate and specific growth rate, respectively as compared to P. pseudomallei. In addition, P. aeruginosa exhibited higher chemical oxygen demand (COD) and biochemical oxygen demand (BOD) reduction rates as compared to the strain P. pseudomallei.

Phenol degradation and toxicity assessment upon biostimulation to an indigenous Rhizobium Ralstonia taiwanensis.

This study provides a first attempt from a toxicological perspective to put forward, in general terms and explanations, combined toxic interactions and biostimulation strategy upon nutrient medium to Ralstonia taiwanensis for bioremediation. Dose-response analysis clearly revealed that most of the supplemented nutrients tested (except for gluconic acid) synergistically interact with chronic toxicity to phenol, especially at low doses. Acute toxicity based upon adaptation lag is a more appropriate indicator for comparative analysis of toxicity due to similar toxic ranking at almost all effective concentrations. In addition, comparison upon acute and chronic toxicity for various nutrient media also suggests in parallel that acute toxicity is more significant than chronic toxicity possibly as the result of a more sensitive response of adaptation lag to growth in different media. Feasibility of adding extra nutrient substrates (e.g., phenol, gluconic acid, yeast extract, pyruvic acid, acetic acid, and glycerol) to stimulate proliferation of phenol degraders for better phenol degradation performance was also assessed. The results show that using acetic acid as the augmented nutrient source might be the most feasible biostimulation strategy for phenol degradation.

Rapid preparation of total nucleic acids from E. coli for multi-purpose applications.

Separate protocols are commonly used to prepare plasmid DNA, chromosomal DNA, or total RNA from E. coli cells. Various methods for the rapid preparation of plasmid DNA have been developed previously, but the preparation of the chromosomal DNA and total RNA are usually laborious. We report here a simple, fast, reliable, and cost-effective method to extract total nucleic acids from E. coli by direct lysis of the cells with phenol. Five distinct and sharp bands, which correspond to chromosomal DNA, plasmid DNA, 23S rRNA, 16S rRNA, and a mixture of small RNA, were observed when analyzing the prepared total nucleic acids on a regular 1-2% agarose gel. The simple and high-quality preparation of the total nucleic acids in a single tube allowed us to rapidly screen the recombinant plasmid, as well as to simultaneously monitor the change of the plasmid copy number and rRNA levels during the growth of E. coli in the liquid medium.

Group-specific monitoring of phenol hydroxylase genes for a functional assessment of phenol-stimulated trichloroethylene bioremediation.

The sequences of the largest subunit of bacterial multicomponent phenol hydroxylases (LmPHs) were compared. It was found that LmPHs formed three phylogenetic groups, I, II, and III, corresponding to three previously reported kinetic groups, low-K(s) (the half-saturation constant in Haldane's equation for trichloroethylene [TCE]), moderate-K(s), and high-K(s) groups. Consensus sequences and specific amino acid residues for each group of LmPH were found, which facilitated the design of universal and group-specific PCR primers. PCR-mediated approaches using these primers were applied to analyze phenol/TCE-degrading populations in TCE-contaminated aquifer soil. It was found that the aquifer soil harbored diverse genotypes of LmPH, and the group-specific primers successfully amplified LmPH fragments affiliated with each of the three groups. Analyses of phenol-degrading bacteria isolated from the aquifer soil confirmed the correlation between genotype and phenotype. Competitive PCR assays were used to quantify LmPHs belonging to each group during the enrichment of phenol/TCE-degrading bacteria from the aquifer soil. We found that an enrichment culture established by batch phenol feeding expressed low TCE-degrading activity at a TCE concentration relevant to the contaminated aquifer (e.g., 0.5 mg liter(-1)); group II and III LmPHs were predominant in this batch enrichment. In contrast, group I LmPHs overgrew an enrichment culture when phenol was fed continuously. This enrichment expressed unexpectedly high TCE-degrading activity that was comparable to the activity expressed by a pure culture of Methylosinus trichosporium OB3b. These results demonstrate the utility of the group-specific monitoring of LmPH genes in phenol-stimulated TCE bioremediation. It is also suggested that phenol biostimulation could become a powerful TCE bioremediation strategy when bacteria possessing group I LmPHs are selectively stimulated.

A reliable assessment of 8-oxo-2-deoxyguanosine levels in nuclear and mitochondrial DNA using the sodium iodide method to isolate DNA.

A major controversy in the area of DNA biochemistry concerns the actual in vivo levels of oxidative damage in DNA. We show here that 8-oxo-2-deoxyguanosine (oxo8dG) generation during DNA isolation is eliminated using the sodium iodide (NaI) isolation method and that the level of oxo8dG in nuclear DNA (nDNA) is almost one-hundredth of the level obtained using the classical phenol method. We found using NaI that the ratio of oxo8dG/10(5 )deoxyguanosine (dG) in nDNA isolated from mouse tissues ranged from 0.032 +/- 0.002 for liver to 0.015 +/- 0.003 for brain. We observed a significant increase (10-fold) in oxo8dG in nDNA isolated from liver tissue after 2 Gy of gamma-irradiation when NaI was used to isolate DNA. The turnover of oxo8dG in nDNA was rapid, e.g. disappearance of oxo8dG in the mouse liver in vivo after gamma-irradiation had a half-life of 11 min. The levels of oxo8dG in mitochondrial DNA isolated from liver, heart and brain were 6-, 16- and 23-fold higher than nDNA from these tissues. Thus, our results showed that the steady-state levels of oxo8dG in mouse tissues range from 180 to 360 lesions in the nuclear genome and from one to two lesions in 100 mitochondrial genomes.