Dual antibacterial mechanism of [K4K15]CZS-1 against Salmonella Typhimurium: a membrane active and intracellular-targeting antimicrobial peptide.

Salmonella genus is a leading cause of food-borne infections with strong public health impact and economic ramifications. The development of antimicrobial resistance added complexity to this scenario and turned the antibiotic drug discovery into a highly important challenge. The screening of peptides has served as a successful discovery platform to design new antibiotic candidates. Motivated by this, the antimicrobial and cytotoxic properties of three cruzioseptins against Salmonella Typhimurium and RAW 264.7 murine macrophage cells, respectively, were investigated. [K4K15]CZS-1 was the most potent antimicrobial peptide identified in the screening step with a minimum inhibitory concentration (MIC) of 16 µg/mL (7.26 µM) and moderate cytotoxicity. From a structural point of view, in vitro and in silico techniques evidenced that [K4K15]CZS-1 is a α-helical cationic antimicrobial peptide. In order to capture mechanistic details and fully decipher their antibacterial action, we adopted a multidimensional approach, including spectroscopy, electron microscopy and omics analysis. In general lines, [K4K15]CZS-1 caused membrane damage, intracellular alterations in Salmonella and modulated metabolic pathways, such as the tricarboxylic acid (TCA) cycle, fatty acid biosynthesis, and lipid metabolism. Overall, these findings provide deeper insights into the antibacterial properties and multidimensional mode of action of [K4K15]CZS-1 against Salmonella Typhimurium. In summary, this study represents a first step toward the screening of membrane-acting and intracellular-targeting peptides as potential bio-preservatives to prevent foodborne outbreaks caused by Salmonella.

Study of creosote transport properties in sandy and clay soils.

Creosote is an organic pollutant formed by a complex mixture of highly toxic and carcinogenic compounds and classified as a dense non-aqueous phase liquid (DNAPL). Its migration depends on media and fluid properties that control the multiphase flow in the subsurface. Residual saturation and hydraulic conductivity are essential parameters to accurately simulate fluid displacement in porous media. This work shows the behavior of creosote in porous medium for sandy and clay soils, collected in a contaminated area in the state of São Paulo, Brazil. Creosote retention was evaluated and compared to water. The retention curve parameters were obtained based on van Genuchten and Brooks and Corey models. The hydraulic conductivities of creosote and water are presented for both soils. The results show that, in the clay soil, water was more retained than creosote, while in the sandy soil, creosote retention was higher. The hydraulic conductivity values obtained in the clay soil show a difference of two orders of magnitude between creosote and water. Although creosote is a viscous fluid, it presents considerable mobility in the clay soil, which is relevant in remediation processes. This study advances our knowledge about DNAPL behavior in clay and sand, and no other study of creosote parameters in these porous media was found. A more accurate estimate of the time required for a liquid spill to reach groundwater can then be predicted, so that appropriate actions can be taken and risk management can be carried out.

Stoichiometric excesses of H2O2 as dosimetry strategy: proof of concept for UVC-H2O2, dark-Fenton, and UVC-Fenton.

Hydrochlorothiazide (HCT) is a pharmaceutical micropollutant highly toxic to the environment, being absolutely necessary to oxidize it completely to CO2. Here, the variables stoichiometric H2O2 excess for (a) degradation and (b) mineralization are defined and used as metric to quantify the dosimetry of the H2O2. So that, dose of H2O2 qualifies being under- and over-dose respectively for values below and above such standards. In this work, these concepts have been elucidated across AOPs regarding the H2O2 degradation excess, whereas only UVC-Fenton was used regarding the H2O2 mineralization excess. At a H2O2 mineralization excess of 0.68 (equivalent to degradation excess of 36.74), oxidation via UVC-H2O2 enables absolute (100%) HCT degradation within 60 min; however, the mineralization of HCT demonstrated limited optimization for all AOPs employed in the beaker-like reactor of this work, being the underlying reasons investigated hereby. At best, 26.70% HCT mineralization was observed within 60 min of UVC photo-Fenton using an initial 2.00 H2O2 mineralization excess. Such mineralization of 26.7% is unexpectedly low considering that, in addition, the residual H2O2 concentration almost fully depletes within 30 min of UVC-Fenton oxidation. Taken all that together, the loss of H2O2 due its decomposition induced by the risen temperature from 28 to 70ºC very likely were the underlying reason preventing better mineralization performance. We successfully demonstrated 18% of mean efficiency of radical •OH consumption signals that the overheating is indeed a designer problem with the photo-reactor since a well-refrigerated photo-reactor shows a mean efficiency of 38% for the same H2O2 excess.

Sunlight-driven environmental photodegradation of 2-chlorobiphenyl (PCB-1) in surface waters: kinetic study and mathematical simulations.

Polychlorinated biphenyls (PCBs) are a family of highly toxic, resistant, and persistent organic pollutants, among which 2-chlorobiphenyl (PCB-1) is one of the simplest. Most studies on PCBs' photochemistry are limited to their direct photolysis, while the important role of reactive photo-induced species (RPS) (hydroxyl radicals, HO●; singlet oxygen, 1O2; and triplet excited states of chromophoric dissolved organic matter, 3CDOM*) in removing PCBs in natural waters through indirect photolysis has not yet been evaluated. In this work, the rate constants of the reactions between aqueous PCB-1 and RPS were obtained under simulated solar radiation (450-W Xenon lamp and an AM 1.5 global filter) by competition kinetics, and the effects of the initial pollutant concentration and the physicochemical characteristics of the water were investigated. The direct photolysis quantum yield of PCB-1 in the range 290-800 nm was found as 1.60 × 10-2 mol Einstein-1. The value of kPCB-1,HO● = (6.80 ± 0.09) × 109 L mol-1 s-1 is in good agreement with the literature. For 1O2, kPCB-1,1O2 = (1.13 ± 0.20) × 106 L mol-1 s-1, while for 3CDOM*, kPCB-1,3CBBP* = (2.44 ± 0.04) × 109 L mol-1 s-1 and kPCB-1,3AQ2S* = (3.36 ± 0.04) × 109 L mol-1 s-1 were obtained using 4-benzoylbenzoic acid (CBBP) and anthraquinone-2-sulfonate (AQ2S) as CDOM proxies, respectively. These results show that the main pathways involved in PCB-1 photodegradation are the reactions with HO● and 3CDOM* together with direct photolysis. In addition, the photodegradation of PCB-1 in sunlit waters was simulated using the kinetic model APEX (Aqueous Photochemistry of Environmentally Occurring Xenobiotics). According to simulations, a greater influence of the water depth and dissolved organic carbon concentration (DOC) on the persistence of PCB-1 is expected, being only slightly influenced by the concentrations of nitrite, nitrate, and bicarbonate. Finally, based on data reported for Brazilian surface waters, the average half-life (t1/2) of PCB-1 is expected to vary from 2 to 14 days. In particular, the t1/2 in the Paranapanema River is estimated at 7 to 8 days.

Chlorella vulgaris phycoremediation at low Cu+2 contents: Proteomic profiling of microalgal metabolism related to fatty acids and CO2 fixation.

The aim of this work was to correlate metabolic changes with copper ions (Cu+2) bioremediation by microalgae C. vulgaris 097 CCMA-UFSCar at low Cu+2 content. The metabolic effects include proteome changes related to fatty acid biosynthesis (value-added product) and carbon fixation (climate change mitigation). Cu+2, even at low concentration, showed a significant negative impact on C. vulgaris growth. The microalgal bioremediation reached 100, 74, 38 and 26% for Cu+2 content at 0.1; 0.3; 0.6 and 0.9 mg L-1, respectively. Regarding proteomics, the numbers of proteins reduced (≈37%) from 581 proteins (control) to 369 proteins (0.9 mg of Cu+2 L-1) compared to control. The microalgal CO2 fixation is strictly related to the Calvin cycle, particularly phase 1, in which ribulose bisphosphate carboxylase large chain (RuBisCO) produces two phosphoglycerate molecules from CO2 and ribulose 1,5-bisphosphate. Then, phosphoglycerate can be metabolically reduced into glucose. When compared to control, the RuBisCO was underexpressed (≈50%). Similar changes in proteomic profiling of metabolism-related to fatty acid biosynthesis was observed. Nevertheless, no protein was found for the cultivation at 0.9 mg of Cu+2 L-1. Thus, the analysis of C. vulgaris proteomic data indicated that even at low concentration, Cu+2 lead to drastic metabolic changes.

Copper mining bacteria: Converting toxic copper ions into a stable single-atom copper.

The chemical synthesis of monoatomic metallic copper is unfavorable and requires inert or reductive conditions and the use of toxic reagents. Here, we report the environmental extraction and conversion of CuSO4 ions into single-atom zero-valent copper (Cu0) by a copper-resistant bacterium isolated from a copper mine in Brazil. Furthermore, the biosynthetic mechanism of Cu0 production is proposed via proteomics analysis. This microbial conversion is carried out naturally under aerobic conditions eliminating toxic solvents. One of the most advanced commercially available transmission electron microscopy systems on the market (NeoArm) was used to demonstrate the abundant intracellular synthesis of single-atom zero-valent copper by this bacterium. This finding shows that microbes in acid mine drainages can naturally extract metal ions, such as copper, and transform them into a valuable commodity.

Extracellular carotenoid production and fatty acids profile of Parachlorella kessleri under increased CO2 concentrations.

Large-scale cultivations of photoautotrophic microorganisms represent a very promising and potentially cost-effective alternative for climate change mitigation, when associated to the co-production of high value bioproducts, such as fatty acids and carotenoids, considering the growing demand for natural products. During microalgae cultivation, CO2 enrichment is a requirement to reach high productivities, although high CO2 levels are normally stressful to microalgae. On the other hand, cellular stress is a well reported strategy to induce carotenoid and fatty acids production. This work evaluated extracellular carotenoid production from the mangrove-isolated microalga Parachlorella kessleri cultivated under 5, 15 and 30% CO2 in stirred tank photobioreactors. In the 10th day of cultivation, CO2 supply was interrupted until the end of the cultivation (14th day), causing a stressful and imperative condition for microalgae cells to release the red pigment. Growth kinetics, physiological parameters and bioproducts production were evaluated. Growth kinetics were similar under all tested conditions and differences were not statistically significant, with the highest values of µmax, biomass concentration, lipid content and CO2 fixation rate of 0.77 d-1, 1.24 g L-1, 241 mg g-1 (dw) and 165 mg L-1 d-1, respectively. In contrast, total carotenoid concentrations varied significantly (p < 0.01), with the highest concentration of 0.030 µg mL-1 under 5% CO2. The produced red pigment presented antioxidant activity and characteristics of carotenoids confirmed by UV-vis and tandem mass spectrometry (MS/MS). The fatty acid profiles in the biomass varied in response to CO2 levels in the cultivations. In general, higher CO2 concentrations (15 and 30%) favored the production of saturated and mono-unsaturated fatty acids, suitable as biodiesel feedstock, while drastically decreased the production of the polyunsaturated.

Photochemical persistence of sulfa drugs in aqueous medium: kinetic study and mathematical simulations.

This study aimed at investigating the photochemical behavior of sulfa drugs containing five and six-membered heterocyclic substituents (sulfamethoxazole (SMX) and sulfadiazine (SDZ), respectively), in an aqueous medium. Despite their importance, studies devoted to the use of photochemical models to predict the environmental phototransformation of pollutants in surface waters, by combining laboratory results and natural aquatic systems parameters, are still scarce in the scientific literature. In this work, the second-order reaction rate constants of SDZ and SMX with hydroxyl radicals (●OH), singlet oxygen (1O2), and triplet excited states of chromophoric dissolved organic matter (3CDOM*) were experimentally determined at pH 7, using the competition kinetics approach. The results show that ●OH and 3CDOM* are the key species involved in sulfonamide degradation, with anionic SMX, most prevalent at pH 6-9, being degraded much slower than the anionic form of SDZ. Moreover, SDZ and SMX photodegradation in natural water samples (spring-fed natural pond, public supply reservoir, and sea water) was significantly enhanced relative to depletion in pure water. Finally, from mathematical simulations of the sunlight-driven sulfonamide degradation, half-life times were predicted for these drugs varying from less than 2 to about 90 days, depending on the water depth, concentration of key species (DOC, HCO3-, NO2-, CO32-) in natural aqueous systems, as well as on the particular heterocyclic substituent.

Light excess stimulates Poly-beta-hydroxybutyrate yield in a mangrove-isolated strain of Synechocystis sp.

Poly-ß-hydroxybutyrate (PHB) is a biodegradable biopolymer that may replace fossil-based plastics reducing its negative environmental impact. One highly sustainable strategy to produce these biopolymers is the exploitation of photosynthetic microorganisms that use sunlight and CO2 to produce biomass and subsequently, PHB. Exploring environmental biological diversity is a powerful tool to find resilient microorganisms potentially exploitable to produce bioproducts. In this work, a cyanobacterium (Synechocystis sp.) isolated from a contaminated area close to an important industrial complex was shown to produce PHB under different culture conditions. Carbon, nutrients supply and light intensity impact on biomass and PHB productivity were assessed, showing that the highest yield of PHB achieved was 241 mg L-1 (31%dcw) under high light intensity. Remarkably this condition not only stimulated PHB accumulation by 70% compared to other conditions tested but also high cellular duplication rate, maximizing the potential of this strain for PHB production.

Biodegradation of diethyl-phthalate (DEP) by halotolerant bacteria isolated from an estuarine environment.

Phthalates are widely used as plasticizers in many industrial products due to their chemical properties that confer flexibility and durability to building materials, lubricants, solvents, insect repellents, clothing, cosmetics, being widely distributed in the environment. Besides persistent, they are also considered endocrine-disrupting compounds (EDCs), causing a global concern about their release into the environment, once they can alter the reproductive and endocrine health of humans systems. Under natural conditions, photodegradation and hydrolysis rates of phthalates are often very slow; therefore, microbial degradation is a natural way to treat these pollutants. In this context, three bacterial consortia (CMS, GMS and GMSS) were isolated from environmental samples from the Santos Estuarine System (SES) and were able to grow on diethyl-phthalate (DEP) as an only carbon source. From the GMSS consortium, three different strains were isolated and identified as Burkholderia cepacia, Pseudomonas koreensis and Ralstonia pickettii by molecular and mass spectrometry (MALDI-TOF-Biotyper) techniques. Considering there are no reports about Ralstonia genus on phthalates degradation, this strain was chosen to proceed the kinetics experiments. Ralstonia pickettii revealed a great ability to degrade DEP (300 mg/L) in less than 24 h. This is the first report implicating R. pickettii in DEP degradation.

Increased P3HB Accumulation Capacity of Methylorubrum sp. in Response to Discontinuous Methanol Addition.

An alternative for non-biodegradable oil-based plastics has been the focus of many researchers throughout the years. Polyhydroxyalkanoates (PHAs) are potential substitutes due to their biodegradable characteristic and diversity of monomers that allow different biopolymer compositions and physical-chemical properties suitable for a variety of applications. The most well-known biopolymer from this class, poly(3-hydroxybutyrate) (P3HB), is already produced industrially, but its final price cannot compete with the oil-based plastics. As a low-volume high-value bioproduct, P3HB must be produced through a cheap and abundant feedstock, with high productivity and a feasible purity process in order to become an economically attractive bioproduct. In this scenario, we report a methylotrophic strain isolated from an estuarine contaminated site identified as Methylorubrum sp. highly tolerant to methanol and with great accumulation capacity of 60% (CDW) in 48 h through a simple strategy of batch fermentation with discontinuous methanol addition that could help lower P3HB's processing costs and final price.

Novel insights on the versatility of biohydrogen production from sugarcane vinasse via thermophilic dark fermentation: Impacts of pH-driven operating strategies on acidogenesis metabolite profiles.

An innovative application of the anaerobic structured-bed reactor (AnSTBR) in thermophilic dark fermentation of sugarcane vinasse targeting biohydrogen (bioH2) production was assessed. A detailed metabolite monitoring program identified the major substrates and primary metabolic pathways within the system. Increasing the applied organic loading rate positively affected bioH2 production, reaching 2074 N mL-H2 L-1 d-1 and indicating an optimal load of approximately 70 kg-COD m-3 d-1. Controlling the fermentation pH (5.0-5.5) was the primary strategy to maintain bioH2-producing conditions, offsetting negative impacts associated with the compositional variability of vinasse. Metabolic correlations pointed out lactate as the primary substrate for bioH2 production, indicating its accumulation as evidence of impaired reactors. The versatility of the acidogenic system was confirmed by identifying three major metabolic pathways according to the pH, i.e., lactate-producing (pH <5.0), bioH2-/butyrate-producing (pH = 5.0-5.5) and bioH2-producing/sulfate-reducing (pH >6.0) systems, which enables managing the operation of the reactors for diversified purposes in practical aspects.

Isolation of Bisphenol A-Tolerating/degrading Shewanella haliotis Strain MH137742 from an Estuarine Environment.

The human exposure to bisphenol A (BPA) occurs frequently. Once, this compound was one of the highest volume chemicals produced worldwide and used as a plasticizer in many products. However, even at low concentration, it can cause severe damage to the endocrine system because of its endocrine disruptor activity. Thus, mitigation studies to remove or reduce this contaminant from the environment are essential. An alternative method of removing it from the environment is the use of bioremediation processes to the selected bacteria isolated from a BPA-impacted area. In this work, four halotolerant strains were isolated from the Santos Estuary System, one of the most important Brazilian examples of environmental degradation. In the present work, one strain presented strong BPA tolerance and high BPA-degrading activity and could grow in a minimum medium containing BPA as the main carbon source. Strain MH137742 was identified as Shewanella haliotis, based on 16S rRNA gene sequencing and mass spectrometry identification by MALDI-TOF Biotyper. Shewanella haliotis was able to tolerate up to 150 mg L-1 of BPA and biotransform 75 mg L-1 in 10 h in a liquid culture medium. Based on the analysis of the produced metabolites by LC-MS, it was possible to predict the metabolic pathway used by this microorganism to degrade the BPA.

Copper biosorption from an aqueous solution by the dead biomass of Penicillium ochrochloron.

The present study investigated the effect of contact time, the initial concentration of metal ions, and the biomass dose on the Cu(II) biosorption from an aqueous solution using dead biomass of filamentous fungus Penicillium ochrochloron, which was isolated at the Sossego mine, a copper-contaminated site located in Canaã dos Carajás city, Brazil. The Cu(II) biosorption started rapidly and increased gradually until the equilibrium was reached at 20 min. The Cu(II) uptake decreased as the initial Cu(II) concentration increased, reaching the saturation at 200 mg/L. The Cu(II) biosorption was considerably higher using 0.2 g than 0.5 g of the biomass in 50 mL of solution. The average biosorption capacity of Cu(II) was 7.53 mg/g and the maximum Cu(II) removal 75.0%. The Freundlich and Langmuir isotherm models adequately described the adsorption data. Our results evidenced that the dead biomass of P. ochrochloron has a great potential as a biosorbent to remove copper from an aqueous solution. Therefore, it could be explored for the development of the environmental recovery process.

Copper biosorption from an aqueous solution by the dead biomass of Penicillium ochrochloron

The present study investigated the effect of contact time, the initial concentration of metal ions, and the biomass dose on the Cu(II) biosorption from an aqueous solution using dead biomass of filamentous fungus Penicillium ochrochloron, which was isolated at the Sossego mine, a copper-contaminated site located in Canaã dos Carajás city, Brazil. The Cu(II) biosorption started rapidly and increased gradually until the equilibrium was reached at 20 min. The Cu(II) uptake decreased as the initial Cu(II) concentration increased, reaching the saturation at 200 mg/L. The Cu(II) biosorption was considerably higher using 0.2 g than 0.5 g of the biomass in 50 mL of solution. The average biosorption capacity of Cu(II) was 7.53 mg/g and the maximum Cu(II) removal 75.0%. The Freundlich and Langmuir isotherm models adequately described the adsorption data. Our results evidenced that the dead biomass of P. ochrochloron has a great potential as a biosorbent to remove copper from an aqueous solution. Therefore, it could be explored for the development of the environmental recovery process.

Rapid bacteria identification from environmental mining samples using MALDI-TOF MS analysis.

Copper mining has polluted soils and water, causing a reduction of the microbial diversity and a change in the structure of the resident bacterial communities. In this work, selective isolation combined with MALDI-TOF MS and the 16S rDNA method were used for characterizing cultivable bacterial communities from copper mining samples. The results revealed that MALDI-TOF MS analysis can be considered a reliable and fast tool for identifying copper-resistant bacteria from environmental samples at the genera level. Even though some results were ambiguous, accuracy can be improved by enhancing reference databases. Therefore, mass spectra analysis provides a reliable method to facilitate monitoring of the microbiota from copper-polluted sites. The understanding of the microbial community diversity in copper-contaminated sites can be helpful to understand the impact of the metal on the microbiome and to design bioremediation processes.

Estudo da caracterização da borra de petróleo e processo de extração do óleo / Study of oil sludge characteristics and oil extraction process

RESUMO: Nesse trabalho, objetivou-se recuperar o óleo presente na borra oleosa por processo de extração, a fim de reutilizá-lo como combustível. Foram aplicados dois planejamentos experimentais: fatorial fracionado e Doehlert. Através da caracterização da borra oleosa (análises físico-químicos, elementar CHN e S, orgânicas e inorgânicas), constatou-se que a borra oleosa utilizada é constituída de 36,2% de óleo, 16,8% de cinzas, 40% de água e 7% de compostos voláteis. A eficiência média do processo de extração foi 70%. Entretanto, a análise estatística mostrou que o modelo quadrático não se ajustou bem ao processo, devido à complexidade do material estudado. Por outro lado, aplicando-se a modelagem de RNA, o coeficiente de determinação foi de 87,5%, mostrando-se bastante satisfatório.

ABSTRACT: This work aimed to recover the oil present in oily sludge by extraction process in order to reuse it as fuel. Two experimental designs were applied: fractional factorial and Doehlert. Through characterization of the oily sludge (physico-chemical analysis, CHN and S elemental, inorganic and organic), it was found that the oily sludge used consists of 36.2% oil, 16.8% ash, 40% water and 7% volatile compounds. The efficiency obtained in the oil extraction process was 70%, in average. However, statistical analysis showed that the quadratic model did not satisfactorily the process due to the complexity of the studied material. By the other hand, applying ANN the coefficient of determination became 87.5% that is quite satisfactory.

Extra and intracellular synthesis of nickel oxide nanoparticles mediated by dead fungal biomass.

The use of dead biomass of the fungus Hypocrea lixii as a biological system is a new, effective and environmentally friendly bioprocess for the production and uptake of nickel oxide nanoparticles (NPs), which has become a promising field in nanobiotechnology. Dead biomass of the fungus was successfully used to convert nickel ions into nickel oxide NPs in aqueous solution. These NPs accumulated intracellularly and extracellularly on the cell wall surface through biosorption. The average size, morphology and location of the NPs were characterized by transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The NPs were mainly spherical and extra and intracellular NPs had an average size of 3.8 nm and 1.25 nm, respectively. X-ray photoelectron spectroscopy analysis confirmed the formation of nickel oxide NPs. Infrared spectroscopy detected the presence of functional amide groups, which are probable involved in particle binding to the biomass. The production of the NPs by dead biomass was analyzed by determining physicochemical parameters and equilibrium concentrations. The present study opens new perspectives for the biosynthesis of nanomaterials, which could become a potential biosorbent for the removal of toxic metals from polluted sites.

Nickel oxide nanoparticles film produced by dead biomass of filamentous fungus.

The synthesis of nickel oxide nanoparticles in film form using dead biomass of the filamentous fungus Aspergillus aculeatus as reducing agent represents an environmentally friendly nanotechnological innovation. The optimal conditions and the capacity of dead biomass to uptake and produce nanoparticles were evaluated by analyzing the biosorption of nickel by the fungus. The structural characteristics of the film-forming nickel oxide nanoparticles were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). These techniques showed that the nickel oxide nanoparticles had a size of about 5.89 nm and were involved in a protein matrix which probably permitted their organization in film form. The production and uptake of nickel oxide nanoparticles organized in film form by dead fungal biomass bring us closer to sustainable strategies for the biosynthesis of metal oxide nanoparticles.

Phenol biodegradation by a microbial consortium: application of artificial neural network (ANN) modelling.

In this study, an effective microbial consortium for the biodegradation of phenol was grown under different operational conditions, and the effects of phosphate concentration (1.4 g L(-1), 2.8 g L(-1), 4.2 g L(-1)), temperature (25 degrees C, 30 degrees C, 35 degrees C), agitation (150 rpm, 200 rpm, 250 rpm) and pH (6, 7, 8) on phenol degradation were investigated, whereupon an artificial neural network (ANN) model was developed in order to predict degradation. The learning, recall and generalization characteristics of neural networks were studied using data from the phenol degradation system. The efficiency of the model generated by the ANN was then tested and compared with the experimental results obtained. In both cases, the results corroborate the idea that aeration and temperature are crucial to increasing the efficiency ofbiodegradation.