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Peroxdiase is one of the member of oxireductase super family, which has a broad substrate range and a variety of reaction types, including hydroxylation, epoxidation or halogenation of unactivated C-H bonds, and aromatic group or biophenol compounds. Here, we summarized the recently discovered enzymes with peroxidation activity, and focused on the special structures, sites, and corresponding strategies that can change the peroxidase catalytic activity, stability, and substrate range. The comparison of the structural differences between these natural enzymes and the mimic enzymes of binding nanomaterials and polymer materials is helpful to expand the application of peroxidase in industry. In addition, we also reviewed the catalytic application of peroxidase in the synthesis of important organic molecules and the degradation of pollutants. [ABSTRACT FROM AUTHOR]

Biological oxidation is a low-carbon technology for the treatment of As-containing gold ores, but it causes a large amount of acidic As-containing wastewater that is harmful to the environment. This paper proposed a novel, eco-friendly method to treat this wastewater. Thermodynamic analysis, H2PO2− reduction, and wastewater recycling tests were conducted. Thermodynamic analysis indicates the feasibility of the reduction of As(V)/As(III) by H2PO2− or H3PO2 to As0 under acidic conditions. Experimental results confirmed the thermodynamic prediction and showed that H2PO2− could efficiently convert the As (i.e., As(V)/As(III)) in the wastewater to high value-added As0. Under the optimal conditions, 99.61% of As precipitated out, and the obtained As0 had a high purity of 98.5%. Kinetic results showed that the reaction order of H2PO2− concentration was 0.6399, and the activation energy of the H2PO2− reduction process was 34.33 kJ/mol, which is indicative of a mixed-controlled process (20–40 kJ/mol). Wastewater recycling results showed that after recovering As, the wastewater could be reused as a bacterial culture medium. Based on the thermodynamic analysis and experimental and analytical results, hypophosphite reduction mechanisms for removing and recovering As from its acidic wastewater were proposed. The results presented in this paper suggest the feasibility of this one-step H2PO2− reduction approach, which may be promising in treating acidic As-containing wastewater. [ABSTRACT FROM AUTHOR]

In this paper, the mechanism of biological metallurgy technology, commonly used metallurgical micro-organisms and the classification of biological metallurgy technology are introduced. The application of biological metallurgy technology in the gold industry and the main technical types of biological stirring oxidation process and biological heap oxidation process are summarized, the research status of biological oxidation pretreatment of high arsenic, high impurity gold concentrate, and electronic waste resources, as well as the purification and utilization of oxidation solution are introduced emphatically, the future key research directions of biometallurgical technology are pointed out, providing a basis for better promotion and application of biometallurgical technology in the gold field. [ABSTRACT FROM AUTHOR]

Polyolefin plastics play an important role in both production and life due to the excellent characteristics, such as east processing, low price and outstanding performance. It has become the most widely used plastics at present. The main raw materials of polyolefin plastics are non-renewable resources such as coal and oil. Waste polyolefin plastics are difficult to degrade in the natural environment, and will break into small particles. The micro plastics are transferred into lakes, rivers, oceans and soil, which will cause serious impact and damage to the environment and the health of animals and plants. Therefore, in terms of energy conservation and environmental protection, the recycling of polyolefin plastics is a very important topic. Among the recycling methods of polyolefin plastics, oxidative degradation can effectively degrade macromolecular polyolefin plastics to generate high-value small molecule chemical raw materials, realize the recycling and high-value utilization of polyolefin plastics, and provide a good solution to the existing micro plastic pollution problem in the environment. In this paper, the oxidative degradation of polyolefin plastics is studied, and the research progress related to the oxidative degradation in recent years is summarized. The reaction process, oxidation mechanism and degradation products of three oxidative degradation methods, chemical oxidative degradation, biological oxidative degradation and photooxidative degradation, are analyzed and discussed. Based on the current research situation, the development prospect of the oxidative degradation and recovery of polyolefin plastics in the future is also prospected.

The current work investigates the efficacy of acoustic cavitation (AC) based pretreatment as a process intensification method for improving the conventional biological oxidation (BO) treatment of the effluent from common effluent treatment plant (CETP) mainly containing pharmaceutical compounds. The effluent acclimatized with cow dung-based sludge was utilized for the aerobic oxidation with an optimum condition of 1:3 ratio of sludge to effluent and 6 h as duration. COD reduction of 19.58% was achieved with the conventional biological oxidation, which was demonstrated to be improved by incorporating acoustic cavitation-based pretreatment approaches under optimized conditions of 125 W and 70% duty cycle for only AC as well as oxidant loadings as 1000 mg/L for H2O2, 250 mg/L Fe(II) with 1000 mg/L H2O2 for Fenton, 1000 mg/L for KPS and 0.5 L/min for the O3 during the combination approaches. The improved COD reduction after the use of pretreatment approaches followed by the BO of 6 h duration was 29.26%, 72.42%, 85.47%, 45.68% and 69.26% for the AC, AC + H2O2, AC + Fenton, AC + KPS and AC + O3 based approaches respectively. The toxicity assay of the effluent before and after every pretreatment approach using bacterial strains of Staphylococcus aureus and Pseudomonas aeruginosa ensured the biodegradability of the treated effluent as no toxic intermediates could be seen. Overall, the present work elucidated the effectiveness of acoustic cavitation-based pretreatment approaches for the improvement of conventional BO of CETP effluent.

Bio-oxidation leaching test was conducted on a low-grade primary gold mine in Inner Mongolia. The acid consumption of ore, cyanidation, bio-oxidation stirred leaching, column leaching, add sulfur and sulfur concentrate to reduce acid consumption , and impact on gold leaching efficiencies were investigated. The results showed that with grinding fineness at -74 μm 80%, acid leaching for 1h, consumption of sulfur acid at 31 kg/t; After cyanidation for 24 h, the gold leaching efficiencies were 51%~55% ; After Bio-oxidation stirring leaching for 6 d, the sulfur oxidation efficiencies was reaching 80%, and the gold leaching efficiencies was reaching 91.4%; Bio-oxidation column leaching tests on gold ore of particle size at -2 mm 80% for 350 d（oxidation 170 d and cyanide leaching 180 d）, the gold leaching efficiencies was increased by 3.72%~23.54% than the direct cyanide leaching 360 d; The addition of sulfur and sulfur concentrate was not conducive to gold cyanide leaching, and the bio-oxidation of sulfur outside the column could reduce the consumption of sulfuric acid by 15.7 kg/t.

In order to improve the ore-dressing index of a refractory gold ore from Gansu Province, based on the ore property, the flotation-tailings cyanide leaching process, raw ore roasting-cyanide leaching process, and biological oxidation-cyanide leaching process are compared.Results showed that with better conditions, the leaching rates of the biological oxidation-cyanide leaching process are 16.67 and 5.14 percentage points higher.Plus, the biological oxidation process requires less investment and low energy consumption and generates no pollutants; the biological oxidation-cyanide leaching process is more conducive to the effective development and utilization of gold and the leaching rate of 85.46 % can be reached. [ABSTRACT FROM AUTHOR]

A gold concentrate from Xinjiang contains 37. 10 g/t Au, 3. 08 % As, 15. 17 % Fe, and 13. 00 % S. The native gold mainly exists in the form of microfine-particle gold, which accounts for 91. 04 %. The gold leaching rate of the gold concentrate, a typical arsenic-containing microfine-particle refractory gold concentrate, is only 29. 16 % by direct cyanide leaching. According to the characteristics of this gold concentrate, systematic biological oxidation single tank experiment and continuous experiment were carried out. The results showed that under the condition that the grinding fineness of -0. 045 mm accounts for 90. 00 %, the bacteria species HYBBSX-Z1212-TL cultivated by Changchun Gold Research Institute Co., Ltd., oxidation slurry concentration is 18 % and continuous oxidation lasts for 6 d, the oxidation rates of As, Fe and S on the gold concentrate are 96. 84 %, 93. 83 % and 74. 97 % respectively;when the gold in oxidation slag is recovered by cyanidation CIL gold extraction process, the optimal conditions for cyanidation is that the slurry concentration is 33 %, the calcium oxide dosage 15 kg/t, alkali treatment time is 2 h, the sodium cyanide dosage is 20 kg/t, the cyanide leaching time is 48 h，the gold leaching rate is 94. 11 %. [ABSTRACT FROM AUTHOR]

Bio-oxidation of refractory gold ore containing arsenic is a green environmental protection technology.Bio-oxidation of refractory gold ores containing arsenic has some disadvantages, such as a long reaction period and unsatisfactory leaching effect.Therefore, the addition of Ａg+ catalyst to improve its oxidation efficiency is studied, and the influence of different Ag+ mass concentrations and leaching time on the bio-oxidation of refractory gold ore containing arsenic is discussed.The results showed that when 20 mg/L Ａg+ is added, the highest arsenic leaching rate was 53.38 %.The redox potential continues to rise and finally tends to be stable.After Ａg+ addition, the pH rises more than that without Ag+ addition, due to the fact that Ａg+ addition generates more Fe3+ and provides more nutrients for bacteria.The ore samples in different oxidation stages are characterized by XRD, SEM-EDS and XPS, respectively. It is found that the addition of Ag+ can make the ore sample porous, increase arsenic leaching rate, accelerate bioleaching, shorten the bioleaching period, and improve oxidation efficiency. [ABSTRACT FROM AUTHOR]

The oxidation of native and nitrocellulose (NC) treated with ultraviolet radiation and ozone (UV + ozone) by the community of active sludge (AS) microorganisms of treatment facilities, as well as by the combination of AS with sulfate-reducing Desulfovibrio desulfuricans VKM B-1388 and microscopic fungi Fusarium solani VKM F-819, is studied. It is shown that the use of pretreatment significantly increases the degree of decomposition of NC during its subsequent biodegradation by the symbiosis of AS microorganisms with D. desulfuricans and F. solani. The use of mutagenic treatment of AS with nitrosomethyl urea (NMU) allows the biocenosis of AS microorganisms with a contaminant-NC to maintain a high oxidizing ability with good sedimentation properties for 65 days of incubation. The degree of NC decomposition is 24.36%. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nowadays, ammonia nitrogen (NH4+) pollution gets more and more attention in drinking water sources. This study investigated the main behavior of biogeochemical NH4+ from groundwater to surface water in a hyporheic zone (HZ) sediment from a reservoir. The experiments were conducted using synthetic groundwater to investigate ammonium transformation. The results indicated that ammonium concentration decreased, apparently resulting from the influence of microbial oxidation and ion exchange with Ca2+, Mg2+, K+, and Na+. However, all the ammonium in the sediment was oxidized, then the adsorbed NH4+ became bioavailable by being released back when NH4+ concentration decreased in the aqueous phase. The results showed NH4+ behavior in a HZ where the aerobic and anaerobic environments frequently exchange, with different hydrological conditions controlled by a strong coupling between microbial activities, geochemistry, hydrology, and ion exchange. [ABSTRACT FROM AUTHOR]

Copyright of Hydrometallurgy of China is the property of Hydrometallurgy of China Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ingeniería del Agua is the property of Universidad Politecnica de Valencia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRACT Phenazines are secreted metabolites that microbes use in diverse ways, from quorum sensing to antimicrobial warfare to energy conservation. Phenazines are able to contribute to these activities due to their redox activity. The physiological consequences of cellular phenazine reduction have been extensively studied, but the counterpart phenazine oxidation has been largely overlooked. Phenazine-1-carboxylic acid (PCA) is common in the environment and readily reduced by its producers. Here, we describe its anaerobic oxidation by Citrobacter portucalensis strain MBL, which was isolated from topsoil in Falmouth, MA, and which does not produce phenazines itself. This activity depends on the availability of a suitable terminal electron acceptor, specifically nitrate. When C. portucalensis MBL is provided reduced PCA and nitrate, it oxidizes the PCA at a rate that is environmentally relevant. We compared this terminal electron acceptor-dependent PCA-oxidizing activity of C. portucalensis MBL to that of several other gammaproteobacteria with various capacities to respire nitrate. We found that PCA oxidation by these strains in a nitrate-dependent manner is decoupled from growth and strain dependent. We infer that bacterial PCA oxidation is widespread and genetically determined. Notably, oxidizing PCA enhances the rate of nitrate reduction to nitrite by C. portucalensis MBL beyond the stoichiometric exchange of electrons from PCA to nitrate, which we attribute to C. portucalensis MBL’s ability to also reduce oxidized PCA, thereby catalyzing a complete PCA redox cycle. This bidirectionality highlights the versatility of PCA as a biological redox agent. IMPORTANCE Phenazines are increasingly appreciated for their roles in structuring microbial communities. These tricyclic aromatic molecules have been found to regulate gene expression, be toxic, promote antibiotic tolerance, and promote survival under oxygen starvation. In all of these contexts, however, phenazines are studied as electron acceptors. Even if their utility arises primarily from being readily reduced, they need to be oxidized in order to be recycled. While oxygen and ferric iron can oxidize phenazines abiotically, biotic oxidation of phenazines has not been studied previously. We observed bacteria that readily oxidize phenazine-1-carboxylic acid (PCA) in a nitrate-dependent fashion, concomitantly increasing the rate of nitrate reduction to nitrite. Because nitrate is a prevalent terminal electron acceptor in diverse anoxic environments, including soils, and phenazine producers are widespread, this observation of linked phenazine and nitrogen redox cycling suggests an underappreciated role for redox-active secreted metabolites in the environment.

The primary carnitine deficiency (PCD) is a genetic disorder of the beta oxidation fatty acids that compromise the energy production. It presents clinically variable and its main manifestation is the dilated cardiomyopathy. The treatment lies on carnitine restoration. We reported a case of a pacient with PCD, who after treatment with oral carnitine restoration had complete remission from the manifestations of the disease. The subject is a teenager, male, born without complications. At the age of months, he showed a progressive dyspnea a deficit on his height and weight gain. At 7 months, is case aggravated, thoracic bulging, intense dyspnea, dysphagia, global hypotonia and whimpering when sleeping. He was diagnosed with dilated cardiomyopathy and treated without significant recovery. The death of his brother from cardiomyopathy motivated an investigation of innate errors of his metabolism. With a wide newborn screening, PCD was indicated. He received treatment with L-carnitine, showing progressive recovery and a normalization. of his cardiac functions. With the correct use of medication, he leads a normal life with minor limitations regarding the physical exercises. Conclusion: Even though it is rare, PCD should be recognized by the health practitioners, due to the elevated morbimortality when not treated. The diagnosis, early treatment and complete admission of the treatment are vital to the quality of life and their good prognosis. [ABSTRACT FROM AUTHOR]

The primary carnitine deficiency (PCD) is a genetic disorder of the beta oxidation fatty acids that compromise the energy production. It presents clinically variable and its main manifestation is the dilated cardiomyopathy. The treatment lies on carnitine restoration. We reported a case of a patient with PCD, who after treatment with oral carnitine restoration had complete remission from the manifestations of the disease. The subject is a teenager, male, born without complications. At the age of months, he showed a progressive dyspnea a deficit on his height and weight gain. At 7 months, is case aggravated, thoracic bulging, intense dyspnea, dysphagia, global hypotonia and whimpering when sleeping. He was diagnosed with dilated cardiomyopathy and treated without significant recovery. The death of his brother from cardiomyopathy motivated an investigation of innate errors of his metabolism. With a wide newborn screening, PCD was indicated. He received treatment with L-carnitine, showing progressive recovery and a normalization. of his cardiac functions. With the correct use of medication, he leads a normal life with minor limitations regarding the physical exercises. Conclusion: Even though it is rare, PCD should be recognized by the health practitioners, due to the elevated morbimortality when not treated. The diagnosis, early treatment and complete admission of the treatment are vital to the quality of life and their good prognosis. [ABSTRACT FROM AUTHOR]

Manganese pollution particularly in the form of dissolved Mn2+ is an important problem in groundwater treatment. The main approaches for Mn2+ removal from groundwater are chemical catalytic oxidation and biological oxidation. Their relative attribution to Mn2+ removal and relationship has not been clarified at the matured stage. An influent of water containing 2.0 and 4.0 mg/L Mn2+ was filtered through columns filled with manganese sand that had either been inoculated with a manganese-adapted microbial community or had been pre-oxidized with potassium permanganate. Either treatment resulted in good manganese removal capacities that maintained a final concentration in the effluent below 0.05 mg Mn2+/L at two concentrations for a period of 130 d. Among the matured period, the direct contribution rate of biological manganese removal was less than 20%. During operation, biological induction and chemical induction were both responsible for the formation of hexagonal Birnessite-type manganese oxide, whose physical characteristics were characterized and determined. Biological oxidation and chemical catalytic oxidation in the maturation of filter media were interlinked through the formation of Birnessite-type manganese oxide. Manganese removal during maturation was mainly attributed to cyclic autocatalysis rather than biological factors. [ABSTRACT FROM AUTHOR]

The proposed method for calculation of the energy value of culture media is based on stoichiometric properties of biological oxidative reactions in the cell and allows for assessment of the nutritional value of organic substrates with consideration of their elemental composition. Three organogen elements (carbon, hydrogen and oxygen) participate in the third stage of catabolism, which is the universal way of biological oxidation of organic nutritive substrate compounds. Their content in the composition of an organic compound (or food substrate) allows for calculation of the amount of energy converted into work during cellular metabolism. The idea to calculate the energy value of a food substrate is based on the principle of energetic conjugation, according to which the useful energy of food substrates within the cell is accumulated in the energy-rich adenosine triphosphate (ATP) bonds formed by biological oxidation of the substrate. Calculation of the energy values of organic substrate is traditionally based on the energy of the abiotic oxidation. The proportion of the useful energy converted into work is not considered in this case. The inherent problem of this approach is that the amount of ATP has been calculated only for several universal metabolites with known oxidative pathways, such as pyruvate and acetate. The proposed method is based on stoichiometric patterns and makes it possible to calculate the amount of ATP from the elemental composition of compounds and the mass fractions of carbon, hydrogen and oxygen. The results of calculation of biological oxidation energy obtained by this method coincide with the published data on biological oxidation metabolites in the citric acid cycle. The presented method, based on the composition of the compounds, allows for calculation of the energy value of any food substrate or culture medium containing a variety of organic compounds, including the case when their metabolic pathway of biological oxidation is unknown and the calculation of the bioenergetic value seems impossible.

The aim of the present work is to investigate the utility of redox chemical delivery prodrug approach for the targeted and sustained release of an alkylating anticancer agent in the brain. The N-methyl-1,4-dihydronicotinate ester of an alkylating nitrogen mustard NM-CDS (4) was synthesized in three step reactions. Structures of all the synthesized compounds were confirmed by UV, IR, (1H&13C) NMR and CHN elemental studies. In vitro chemical oxidation studies with silver nitrate of NM-CDS (4) indicated that it can be readily converted into its corresponding quaternary salt (3) with half life of 8 min. In vitro biological oxidation studies showed facile oxidation in biological media and rate of oxidation followed pseudo first-order kinetics with reasonable half-lives of 32.5 min in rat blood, 24.2 min in human blood and 19.4 min in brain homogenate. The in vivo studies on Sprague–Dawley rats were performed. The NM-CDS (4) at a dose of 40 mg/kg, was injected into rats. At selected time intervals, blood samples and the brains were collected and analyzed by UV spectrophotometer. The results demonstrated that NM-CDS (4) was able to cross the blood–brain barrier (BBB) at detectable concentration, oxidized to its active quaternary salt (Q-salt) (3) and sustained there for some period of time. The in silico ADME descriptors required for CNS activity were determined by computational, online (Molinspiration) and QikProp 3.2 software (Schrodinger, USA) that further indicated that NM-CDS (4) has a good potential to cross the BBB and show CNS antitumor activity.

Biogas purification via water scrubbing produces effluent containing dissolved CH 4 , H 2 S, and CO 2 , which should be removed to reduce greenhouse gas emissions and increase its potential for water regeneration. In this study, a reactor built with air supplies at the top and bottom was utilized for the treatment of biogas purification effluent through biological oxidation and physical stripping processes. Up to 98% of CH 4 was removed through biological treatment at a hydraulic retention time of 2 hr and an upper airflow rate of 2.02 L/day. Additionally, a minimum CH 4 concentration of 0.04% with no trace of H 2 S gas was detected in the off gas. Meanwhile, a white precipitate was captured on the carrier showing the formation of sulfur. According to the developed mathematical model, an upper airflow rate of greater than 2.02 L/day showed a small deterioration in CH 4 removal performance after reaching the maximum value, whereas a 50 L/day bottom airflow rate was required to strip the CO 2 efficiently and raise the effluent pH from 5.64 to 7.3. Microbiological analysis confirmed the presence of type 1 methanotroph communities dominated by Methylobacter and Methylocaldum. However, bacterial communities promoting sulfide oxidation were dominated by Hyphomicrobium. Unlabelled Image [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A biological-chemical treatment of a complex industrial wastewater has been studied. • Real Hazardous wastewater consisted of a mixture of special chemical effluents. • Acclimation of the aerobic culture used was successfully investigated. • Solar photocatalytic ozonation was able to remove biorecalcitrant compounds. Abstract The feasibility of the treatment of a complex industrial wastewater by aerobic biodegradation in a sequential batch reactor (SBR) followed by ozone-based advanced oxidation processes (AOPs) has been studied. The industrial wastewater had high organic load (TOC > 3 g L−1, COD > 12 g L−1, BOD 5 > 2 g L−1) including some toxic/harmful compounds and high concentration of metal and other inorganic species. SBR treatment of the industrial wastewater diluted with urban wastewater (dilution 1:5), was successful after complete acclimation of the mixed culture (i.e., >50% COD and TOC removals). Nevertheless, the SBR effluent was still not acceptable to be disposed into the environment (c.a. COD 850 mg L−1) so ozonation, solar photo-ozonation and solar photocatalytic ozonation processes were investigated as further polishing treatments. Thus, the sequential combination of aerobic biodegradation and solar photocatalytic ozonation with a TiO 2 -based catalyst led to an effluent suitable for discharge into the aquatic environment according to environmental regulations (COD < 125 mg L−1, BOD 5 < 25 mg L−1). [ABSTRACT FROM AUTHOR]

Changes in the composition of heavy Balakhani oil in the course of its biodegradation in soil were studied. The ability of microorganisms isolated from oil-contaminated soils to degrade petroleum products of various degrees of condensation (petroleum and its hexane, benzene, and alcohol–benzene fractions) was evaluated. The ways of biological oxidation of heavy oil by hydrocarbon-oxidizing microorganisms were investigated. It was found that the process of biological oxidation of the test oil contributed to dewaxing and aromatization and increased oil oxidation level due to an increase in oxygen-containing groups. [ABSTRACT FROM AUTHOR]

Dye wastewater is one of typically non-biodegradable industrial effluents. A new process linking Fenton’s oxidation with biological oxidation proposed in this study was investigated to degrade the organic substances from real dye wastewater. During the combination process, the Fenton’s oxidation process can reduce the organic load and enhance biodegradability of dye wastewater, which is followed by biological aerated filter (BAF) system to further remove organic substances in terms of discharge requirement. The results showed that 97.6% of chemical oxygen demand (COD) removal by the combination process was achieved at the optimum process parameters: pH of 3.5, H2O2 of 2.0 mL/L, Fe(II) of 500 mg/L, 2.0 h treatment time in the Fenton’s oxidation process and hydraulic retention time (HRT) of 5 h in the BAF system. Under these conditions, COD concentration of effluent was 72.6 mg/L whereas 3020 mg/L in the influent, thus meeting the requirement of treated dye wastewater discharge performed by Chinese government (less than 100 mg/L). These results obtained here suggest that the new process combining Fenton’s oxidation with biological oxidation may provide an economical and effective alternative for treatment of non-biodegradable industrial wastewater.

Highlights • Current biological processes are challenged by high energy consumption. • Further optimization of biological processes cannot offer an ultimate solution. • Solutions toward energy self-sufficient biological processes need to be addressed. • Energy recovery should be maximized with minimized energy consumption. • Directions toward next-generation biological processes are outlined. Abstract Almost all present biological processes for treating municipal wastewater have been developed based on the philosophy of biological oxidation with high energy consumption and generation of waste sludge. Given such a situation, the fundamental question of what are the possible ways towards energy self-sufficient biological reclamation of municipal wastewater needs to be addressed urgently. Therefore, this review aims to offer a critical view and a holistic analysis of biological treatment processes with the focus on energy self-sufficiency which indeed is a game changer in the future technology development. The way towards energy self-sufficient operation of biological processes is to maximize energy recovery, while to minimize energy consumption. The examples of such process configurations known as A-B processes are thus discussed. Consequently, this review may offer in-depth insights into the possible directions towards the next-generation biological processes for municipal wastewater reclamation which should be designed as a water-energy-resource factory. [ABSTRACT FROM AUTHOR]

In this paper, the leaching behaviour of mechano-chemically activated, refractory, bio-oxidised flotation gold concentrates has been investigated. In particular, the effect of activation parameters (e.g., milling time and speed, and ball to pulp ratio) and cognate physico-chemical changes on the impact of the refractory mineral components in the ore was studied. The results showed that mechano-chemical activation led to reduction in the average particle size and increased surface area and reagent consumption in tandem with remarkable mineral amorphisation of the bio-oxidised products. The gold yield increased by a maximum of ~1.8 times after 24 h of cyanide leaching, irrespective of the magnitude of milling speed, milling time, ball to pulp ratio and the degree of mineral amorphisation. Furthermore, the increase in reagent consumption was consistent with increasing mineral particle stress and exposure of reactive gangue mineral phases (e.g., sulphate minerals), a factor that least influenced the gold yield. It appears that the improvement in gold extraction efficacy was due to gold surface cleaning, creation of pores/crevices that are linked to gold sites, and disintegration of gold-gangue mineral agglomerates that encapsulated gold particles. The findings were consistent with the nature of refractoriness and necessary for understanding ways of mitigating gold refractoriness in bio-oxidised flotation concentrates. [ABSTRACT FROM AUTHOR]

In this work, furfural was effectively converted to furoic acid (FCA) by using biological macromolecules as raw materials in tandem reaction with chemical biological catalysts. Firstly, a biochar-based heterogeneous catalyst Sn-FS-RH was prepared using equal mass of fish scale (FS) and rice husk (RH) as carriers. Different biomasses (such as poplar wood, winter bamboo shoot shell, corn cob, corn straw, reed leaf, peanut shell, rape straw, and potato shell) were transformed into furfural with Sn-FS-RH in deep eutectic solvent choline chloride:Maleic acid (ChCl:MLA)-H 2 O (10:90, v/v; 170 °C), and the furfural yield from corn cob-derived xylose reached the highest (70.5% yield, based on xylose) after 15 min of catalysis. The mechanism of Sn-FS-RH-catalyzed the transformation of lignocellulose to furfural was interpreted in ChCl:MLA-H 2 O. One liter of xylose-hydrolysate was obtained after acid hydrolysis of biomass. The preparation of FUR was generally carried out in a 10 liter of autoclave reactor containing 75 g biomass, 36 g Sn-FS-RH catalyst, 100 g ChCl:MLA, and 20 g ZnCl 2. The reactor was stirred at 170 ℃ for 15 min at 500 rpm. It was observed that the by-products (formic acid, levulinic acid, and 5-hydroxymethylfurfural) formed in the transformation of lignocellulose to furfural had somewhat inhibitory effect on the formation of furoic acid from furfural bioconversion. After 24–72 h, Escherichia coli HMFOMUT cells containing dehydrogenase could transform fully furfural derived from different biomass (30–90 mM) into furoic acid. This two-step chemoenzymatic strategy was an efficient way to transform biomacromolecules into biofurans in a sustainable medium. [Display omitted] • A biochar catalyst Sn-FS-RH was prepared using fish scale and rice husk as carriers. • Different biomasses were transformed into furfural in chloride:Maleic acid (10 wt%). • The highest furfural yield from corn cob reached 55% with Sn-FS-RH. • HMFOMUT cell transformed fully biomass-derived furfural to furoic acid. • This chemoenzymatic strategy was an efficient way to transform biomass to biofurans. [ABSTRACT FROM AUTHOR]

The paper deals with the theoretical issues of biological oxidation of oil hydrocarbons from alkanes to polycyclic aromatics. We analyze the mechanisms of biochemical processes of decomposition of oil components and provide an overview of data from common databases. Studies of microbial communities of natural oil seeps in the Uzon caldera are described in detail. It is the first study of ecophysiological characteristics of oil-degrading microorganisms isolated from thermal oil seeps of the caldera.

The degradation of native and pretreated nitrocellulose (NC) by the microscopic fungus Fusarium solani VKM F-819 and a mixed culture of the fungus with a sulfate-reducing bacterium Desulfovibrio desulfuricans VKM B-1388 has been studied. It has been shown that NC pretreatment with UV radiation and ozone promoted its subsequent biodegradation. The degradation of the thus treated NC by a mixed culture of F. solani and D. desulfuricans was the most effective as compared to all other treatment options. The NC nitrogen content decreased from 13.38 to 10.03%; the number average (Mn) and weight average (Mw) molecular masses decreased by three and two times, respectively. These magnitudes were achieved after 5 days of incubation of the pretreated NC. The obtained data can be used to further develop NC degradation technology. [ABSTRACT FROM AUTHOR]

Coka Marin is a polymetallic deposit which in addition to desired metals contains Hq and As, so that the concentrate produced by the ore processing from this deposit cannot be processing in smelter in Bor. Plants for treatments of ore with mentioned content by using pretreatment the biological oxidation exist in world for many years. This plants are proved to be good alternative to pyro metallurgical processes of ore processing. The advantage is ecological and economical. For these reasons it would be useful to investigate the possibility of the application of this procedure on the concentrate obtained from ore Coka Marin.

The oxidation of nitrocellulose (NC) containing 13.38% nitrogen has been investigated. The oxidation process under the action of hard UV radiation and ozone has been conducted for 27 h. As result, the nitrogen content of NC has decreased by less than 4.0%. For oxidation using Desulfovibrio ( D.) desulfuricans sulfate-reducing bacteria, NC has been incubated with these bacteria for 65 days. This processing has reduced the nitrogen content of NC by 1.66-2.8%. D. desulfuricans incubation with NC pretreated with UV light + ozone has decreased the nitrogen content of the sample by at most 2.75% (compared to the baseline). UV + ozone pretreatment enables subsequent NC oxidation by D. desulfuricans: the resulting samples are richer in low-molecular-weight fractions and nitrate and nitro groups, and they reach their maximum extent of oxidation within 16 h of incubation with the bacteria, whereas the untreated samples oxidize to the maximum extent in 38 h. It is likely that the UV + ozone treatment cleaves carbon-carbon bonds in the polymer chain and lowers the degree of polymerization of individual chains, thereby facilitating the penetration of bacteria into the bulk polymer globules and the bacterial oxidation of ester bonds. [ABSTRACT FROM AUTHOR]

The aim of the present work is to investigate the utility of redox chemical delivery prodrug approach for the targeted and sustained release of an alkylating anticancer agent in the brain. The N-methyl-1,4-dihydronicotinate ester of an alkylating nitrogen mustard NM-CDS (4) was synthesized in three step reactions. Structures of all the synthesized compounds were confirmed by UV, IR, (¹H&13C) NMR and CHN elemental studies. In vitro chemical oxidation studies with silver nitrate of NM-CDS (4) indicated that it can be readily converted into its corresponding quaternary salt (3) with half life of 8 min. In vitro biological oxidation studies showed facile oxidation in biological media and rate of oxidation followed pseudo first-order kinetics with reasonable half-lives of 32.5 min in rat blood, 24.2 min in human blood and 19.4 min in brain homogenate. The in vivo studies on Sprague-Dawley rats were performed. The NM-CDS (4) at a dose of 40 mg/kg, was injected into rats. At selected time intervals, blood samples and the brains were collected and analyzed by UV spectrophotometer. The results demonstrated that NM-CDS (4) was able to cross the blood- brain barrier (BBB) at detectable concentration, oxidized to its active quaternary salt (Q-salt) (3) and sustained there for some period of time. The in silico ADME descriptors required for CNS activity were determined by computational, online (Molinspiration) and QikProp 3.2 software (Schrodinger, USA) that further indicated that NM-CDS (4) has a good potential to cross the BBB and show CNS antitumor activity. [ABSTRACT FROM AUTHOR]