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Improvements in biohydrogen production from palm oil mill effluent (POME) has been achieved by optimizing the physicochemical conditions, using an enriched sludge as inoculum. Enrichment of biohydrogen-producing communities in the sludge was first carried out by heat treatment and acclimatization to POME. Response surface methodology (RSM) was then used for optimizing the operational parameters. The factors investigated were temperature, initial pH, and inoculum concentration. The output responses were evaluated based on the biohydrogen yield (YH2), biohydrogen production rate (RH2), and COD removal efficiency. Microbial analysis of the enriched sludge at 100% POME concentration revealed the abundance of the Firmicutes phylum (98%) among the Bacteria population, with Clostridiaceae as the most abundant family. Archaea were inhibited at both 30% and 100% POME concentration. The optimum operational parameters generated by the RSM model were 34.7 °C, pH 5.81, and inoculum size of 14.22% (v/v), with the following predicted outcomes: YH2 of 42.29 mL H2 gCOD−1, RH2 of 106.09 mL L−1 h−1, and COD removal efficiency of 23.66%. Meanwhile, the experimental data generated were as follows: YH2 of 41.18 mL H2 gCOD−1, RH2 of 109 mL L−1 h−1, and COD removal efficiency of 25.96%. The process reliability was further demonstrated in a larger (2.5 L) continuously stirred-tank reactor, with the maximum biohydrogen yield obtained of 282 mL H2 gCOD−1 and COD removal efficiency of 35%. Butyric and acetic acids were the dominant soluble metabolites produced. These findings suggest that the RSM model generated was successfully used to optimize biohydrogen production from POME using enriched anaerobic digested sludge.

Arsenic (As) is an increasing threat across the globe, widely known as a non-threshold carcinogen, and it is reaching harmful values in several areas of the world. In this study, the effect of plant growth promoting bacteria (Microbacterium foliorum) on inorganic arsenic (Arsenate) phytoremediation by Melastoma malabathricum plants was investigated through histological analysis and proteome profiling of the M. malabathricum plants. Two-dimensional gel electrophoresis and transmission electron microscopy were used to conduct the proteome and histological analysis. When arsenic-treated cells were compared to untreated cells, substantial changes were found (1) severely altered the morphology of the cells, intensely disturbed; (2) the cell wall was thicker; (3) drastically changed the cytoplasm, the cells were polygonal in shape, different in size (scattered), and relatively dense. Compared to the control group, the ultra-structure of the root cells of the control group revealed intact cytoplasm, vacuole, and cell wall under exposure to As + bacteria that had a minor effect on the cell form. To further understand As + bacteria interaction, proteome profiling of the root cell was analyzed. The As-induced oxidative stress enrichment was confirmed by the up-regulation of tubulin, nucleoside diphosphate kinase, and major allergen during As + bacteria exposure It was observed that the profusion of proteins involved in defence, protein biogenesis, signaling, photosynthesis, nucleoside and energy metabolism was greater in As + bacteria as compared to the rooting out of As only. Overall, it can be obviously seen that the current study demonstrates the effectiveness of phytoremediation by M. foliorum on proteins involved and responsive pathways in dealing with As toxicity in M. malabathricum plant.

Detection of nitrite-ion has become very important for various industrial fields due to its wide application range such as food additives and a rust preventive agent for steels. In this study, we attempted at developing an advanced method to produce layered perovskite-type cuprates based thick-film device for highly sensitive electrochemical sensor for nitrite-ion with a capacity of wide concentration range. Here, layered perovskite-type oxide powders could be synthesized by a polymer precursor method which was deposited on alumina supports with gold electrode by an electrophoretic deposition method. The sensor performance was measured by an amperometric method for nitrite-ion detection. It was found that the Gd2CuO4-based electrode showed fast and good linear responses to nitrite-ion for a wide range of concentration., 第57回セラミックス基礎科学討論会, 2019年1月16日～17日, 仙台国際センター, 宮城, 日本

The global rise in demand for fats and oil has made the palm oil industry grown tremendously over the last decades in countries like Indonesia, Malaysia, and Thailand. Malaysian agro-industrial sector alone accounts for about 51% of the world’s palm oil production and 62% of the world’s export. The sector has generated billions of dollars in revenues, and tonnes of wastes too. Palm oil mill effluent (POME) is the most abundant waste generated during the crude oil extraction process. Efficient and effective POME treatment technologies are still being actively investigated. POME has great potential as a substrate for biohydrogen production due to the high content of degradable organic matter. Dark fermentation, among the various biological processes for biohydrogen production, is highly favored due to the lower cost and low energy requirement. However, achieving a high biohydrogen yield is the main challenge, due to the co-production of organic acids. Additional treatment steps using bioelectrochemical systems (BES), such as microbial electrolysis cell (MEC), can provide the much-needed solution. Enhanced biohydrogen production can potentially be achieved when dark fermentation is coupled with MEC, with better POME treatment. Microbial fuel cell (MFC) can provide additional treatment step, with simultaneous electricity generation. This chapter reviews the various dark fermentation technologies that have been employed in producing biohydrogen from POME, the methods employed to improve biohydrogen yield, the advancements in BES, and the potential integration with dark fermentation for enhanced biohydrogen production.

The feasibility of Citrobacter freundii A1 and Enterococcus casseliflavus C1 bacterial consortium under sequential facultative anaerobic-aerobic treatment for complete dye degradation using AR-27 dyes shows 98% decolourisation and 100% COD removal after 72 hours treatment. Moreover, the UV-Vis spectroscopy and Fourier Transform Infrared (FTIR) Spectroscopic analysis confirmed that the azo linkage was cleaved after the decolourisation occurred. While, the cyclic voltammetry analysis also shows that the decolourisation of AR-27 by C. Freundii A1 and E. Casseliflavus C1 was an irreversible reaction and the detection of oxidation reaction under agitation proved the presences of AR-27 degradation process. Furthermore, the HPLC analysis has confirmed the AR-27 degradation through the decrease in catechol concentration.

Arsenic contamination has been widely recognized as one of the most consequential environmental pollutants due to its anthropogenic activities. Arsenic toxicity and remediation have become the focus of many institutions, including industries, environmental groups, and the general public. The treatment of arsenic contamination is of irrefutable significance to lower floras and faunas, humanity, and their living ecosystem. This review comprehensively examines different arsenic toxicities to the environment and their associated removal techniques. To begin with, the appraisal focuses on the general background of arsenic occurrences in the environment, its related health hazards, and measurement techniques. In addition, it also provides a comprehensive discussion of how arsenic impurities can be removed from the environment using diverse established and advanced technologies like adsorption, ion exchanges, electrokinetic processes, electrocoagulation, chemical precipitation, phytoremediation, nano phytoremediation, membrane technology, and phytobial remediation. Finally, the pros and cons of the remediation/removal methods are enumerated, as well as their principal ongoing accomplishments. The simplicity, low cost, and easy operational procedure of adsorption technique and use of novel functional materials such as graphite oxides, metal organic frameworks, carbon nanotubes and other new forms of functional materials are better future alternatives for arsenic removal.

Phytobial remediation is an innovative tool that uses plants and microbes to mitigate Arsenic (As) contamination of the environment. Recently, plant growth-promoting bacteria (PGPB) that assists phytoremediation has been highly touted for both improving plant metal tolerance and promoting plant growth while achieving the goal of large-scale removal of As. This review focuses on the PGPB characteristics influencing plants and the mechanisms in which they function to overcome/lessen As-induced adversities. Several recent examples of mechanisms responsible for increasing the availability of As to plants and coping with As stresses facilitated by PGPB will be reviewed. Although drawbacks to phytoremediation have been reported, encouraging results have been developed with regular monitoring. Introducing PGPB-assisted phytoremediation of As in a field requires an assessment of the environmental effects of PGPB, especially with respect to the impacts on indigenous bacteria.

One of the biggest challenges of using single-chamber microbial fuel cells (MFCs) that utilize proton-exchange membrane (PEM) air cathode for bioenergy recovery from recalcitrant organic compounds present in wastewater is mainly attributed to their high internal resistance in the anodic chamber of the single microbial fuel cell (MFC) configurations. The high internal resistance is due to the small surface area of the anode and cathode electrodes following membrane biofouling and pH splitting conditions as well as substrate and oxygen crossover through the membrane pores by diffusion. To address this issue, the fabrication of new PEM air-cathode single-chamber MFC configuration was investigated with inner channel flow open assembled with double PEM air cathodes (two oxygen reduction activity zones) coupled with spiral-anode MFC (2MA-CsS-AMFC). The effect of various proton-exchange membranes (PEMs), including Nafion 117 (N-117), Nafion 115 (N-115), and Nafion 212 (N-212) with respective thicknesses of 183, 127, and 50.08 μ, was separately incorporated into carbon cloth as PEM air-cathode electrode to evaluate their influences on the performance of the 2MA-CsS-AMFC configuration operated in fed-batch mode, while Azorubine dye was selected as the recalcitrant organic compound. The fed-batch test results showed that the 2MA-CsS-AMFC configuration with PEM N-115 operated at Azorubine dye concentration of 300 mg L−1 produced the highest power density of 1022.5 mW m−2 and open-circuit voltage (OCV) of 1.20 V coupled with enhanced dye removal (4.77 mg L h−1) compared to 2MA-CsS-AMFCs with PEMs N-117 and N-212 and those in previously published data. Interestingly, PEM 115 showed remarkable reduction in biofouling and pH splitting. Apart from that, mass transfer coefficient of PEM N-117 was the most permeable to oxygen (KO = 1.72 × 10−4 cm s−1) and PEM N-212 was the most permeable membrane to Azorubine (KA = 7.52 × 10−8 cm s−1), while PEM N-115 was the least permeable to both oxygen (KO = 1.54 × 10−4) and Azorubine (KA = 7.70 × 10−10). The results demonstrated that the 2MA-CsS-AMFC could be promising configuration for bioenergy recovery from wastewater treatment under various PEMs, while application of PEM N-115 produced the best performance compared to PEMs N-212 and N-117 and those in previous studies of membrane/membrane-less air-cathode single-chamber MFCs that consumed dye wastewater.

Despite being a key Malaysian economic contributor, the oil palm industry generates a large quantity of environmental pollutant known as palm oil mill effluent (POME). Therefore, the need to remediate POME has drawn a mounting interest among environmental scientists. This study has pioneered the application of Meyerozyma guilliermondii with accession number (MH 374161) that was isolated indigenously in accessing its potential to degrade POME. This strain was able to treat POME in shake flask experiments under aerobic condition by utilising POME as a sole source of carbon. However, it has also been shown that the addition of suitable carbon and nitrogen sources has significantly improved the degradation potential of M. guilliermondii. The remediation of POME using this strain resulted in a substantial reduction of chemical oxygen demand (COD) of 72%, total nitrogen of 49.2% removal, ammonical nitrogen of 45.1% removal, total organic carbon of 46.6% removal, phosphate of 60.6% removal, and 92.4% removal of oil and grease after 7 days of treatment period. The strain also exhibited an extracellular lipase activity which promotes better wastewater treatment. Additionally, Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) analyses have specifically shown that M. guilliermondii strain can degrade hydrocarbons, fatty acids, and phenolic compounds present in the POME. Ultimately, this study has demonstrated that M. guilliermondii which was isolated indigenously exhibits an excellent degrading ability. Therefore, this strain is suitable to be employed in the remediation of POME, contributing to a safe discharge of the effluent into the environment.

This work studied the performance of a laboratory-scale microbial fuel cell (MFC) using a bioanode that consisted of treated clinoptilolite fine powder coated onto graphite felt (TC-MGF). The results were compared with another similar MFC that used a bare graphite felt (BGF) bioanode. The anode surfaces provided active sites for the adhesion of the bacterial consortium (NAR-2) and the biodegradation of mono azo dye C.I. Acid Red 27. As a result, bioelectricity was generated in both MFCs. A 98% decolourisation rate was achieved using the TC-MGF bioanode under a fed-batch operation mode. Maximum power densities for BGF and TC-MGF bioanodes were 458.8 ± 5.0 and 940.3 ± 4.2 mW m−2, respectively. GC-MS analyses showed that the dye was readily degraded in the presence of the TC-MGF bioanode. The MFC using the TC-MGF bioanode showed a stable biofilm with no biomass leached out for more than 300 h operation. In general, MFC performance was substantially improved by the fabricated TC-MGF bioanode. It was also found that the TC-MGF bioanode with the stable biofilm presented the nature of exopolysaccharide (EPS) structure, which is suitable for the biodegradation of the azo dye. In fact, the EPS facilitated the shuttling of electrons to the bioanode for the generation of bioelectricity., Este trabajo estudió el rendimiento de una celda de combustible microbiana (MFC) a escala de laboratorio utilizando un bioanodo que consistía en un polvo fino de clinoptilolita tratado recubierto de fieltro de grafito (TC-MGF). Los resultados se compararon con otro MFC similar que utilizó un bioanodo de fieltro de grafito desnudo (BGF). Las superficies del ánodo proporcionaron sitios activos para la adhesión del consorcio bacteriano (NAR-2) y la biodegradación del colorante mono azoico CI Acid Red 27. Como resultado, se generó bioelectricidad en ambos MFC. Se logró una tasa de decoloración del 98% utilizando el bioanodo TC-MGF en un modo de operación por lotes alimentados. Las densidades de potencia máximas para los bioanodos BGF y TC-MGF fueron 458,8 ± 5,0 y 940,3 ± 4,2 mW m −2, respectivamente. Los análisis de GC-MS mostraron que el tinte se degradaba fácilmente en presencia del bioanodo TC-MGF. El MFC que utilizó el bioanodo TC-MGF mostró una biopelícula estable sin lixiviación de biomasa durante más de 300 h de operación. En general, el rendimiento de MFC mejoró sustancialmente con el bioanodo TC-MGF fabricado. También se encontró que el bioanodo TC-MGF con la biopelícula estable presenta la naturaleza de estructura de exopolisacárido (EPS), que es adecuada para la biodegradación del colorante azoico. De hecho, el EPS facilitó el transporte de electrones al bioanodo para la generación de bioelectricidad.

Natural clinoptilolite (Cli) and chabazite (Cha) were used as the carrier for two types of antibacterial agents: cetylpyridinium chloride (CPC) and silver cations (Ag). CPC-zeolites, Ag-zeolites and CPC-Ag-zeolites were characterized by Energy Dispersive X-ray (EDX) analyzer and Fourier Transform Infrared (FTIR) spectroscopy and proved the attachment of CPC molecules on Ag-zeolite in CPC-Ag-zeolite samples. The determination of Minimum Inhibition Concentration (MIC) against P. aeruginosa and B. subtilis in saline solution and distilled water was performed to observe the effect of chloride ions on the antibacterial activity of the studied samples. From the MIC values, a new modified zeolite with CPC and Ag (CPC-Ag-zeolites) showed better antibacterial activity compared to that of CPC-zeolites and Ag-zeolites and performed well in both saline solution and distilled water.

The ability of the NAR-2 bacterial consortium, consisting of A1, C1, and L17, to degrade the azo dye model, Remazol Black B (RBB), was studied in an upflow packed-bed reactor for continuous sequential microaerophilic–aerobic batch operations. Continuous decolourisation was performed in a borosilicate glass column (12 mm × 20 mm) packed with surfactant-modified clinoptilolite immobilised by the NAR-2 bacterial consortium. In column bioreactor studies, decolourisation was observed at 45 °C and was carried out by varying the flow rates and dye concentrations in a modified P5 medium with pH 7.0 under microaerophilic conditions. A decolourisation of 95.87 % of 0.1 g/L RBB was achieved at a flow rate of 0.2 mL/min under microaerophilic conditions by the immobilised NAR-2 bacterial consortium. An analysis of the decolourised and biodegradation products of the RBB using total aromatic amines showed that a reduction in the RBB resulted in the formation of aromatic amines. On further aerobic degradation for 15 days, the concentration of the amines dropped significantly, from an initial concentration of 34 to 11 mg/L, following the aerobic batch treatment experiment. The findings of this study showed that SMC can be a support material for bacterial cell immobilisation in a single upflow reactor with intermittent microaerophilic–aerobic operations, and it was found to be suitable and eco-friendly for the degradation of azo dyes.

This article presents the design, simulation, and fabrication of a new planar left-handed metamaterial (LHM), which consist of a combination of a modified square rectangular split ring resonator and strip wire. Both structures are on the same plane. The structure is simulated and measured with the microstrip antenna operating at frequency 5.8 GHz. The LHM has been analyzed using Nicolson-Ross-Weir approach to obtain the negative permeability and permittivity at 5.8 GHz. The fabrication of the LHM is on FR-4 board substrate. From the simulation and measurement results, the gain of the microstrip antenna with LHM has increased by 4.0 dB. The return loss of the antenna with LHM is improved to 15.7 dB compare without LHM structure.

Carbon nanoparticles of ca. 9–18 nm diameter (Emperor 2000™) are surface-modified by covalently linking l -dopa-boc (boc-protected l -3,4-dihydroxyphenylalanine) with a surface coverage of approximately 100 per particle (or 3 × 10 13 cm −2 ). In solution environments these redox-active nanoparticles provide chemically stable and pH-sensitive voltammetirc responses (reversible 2-electron 2-proton oxidation) over a pH range from 2 to 12. When mixed into Dowex 50 Wx4 cation exchanger or Dowex 50 1x2 anion exchanger and placed in contact with a glassy carbon electrode in a flow of humidified gas, the l -dopa-boc-modified carbon nanoparticles provide pH-sensitive surface probes to monitor the surface conditions. In a two-terminal cell it is demonstrated that gas flow measurements are possible with both modified cation and anion exchanger particles in contact to glassy carbon electrodes. The anion exchanger particles allow pH control after pre-conditioning in phosphate buffer. Loading-dependent sensitivity to ammonia gas is investigated and high sensitivity to ammonia is observed for Dowex 50 1x2 anion exchanger pre-equilibrated in phosphate buffer pH 3 and decorated with l -dopa-boc-modified carbon nanoparticles. Responses are observed with sequential injections of 1 cm 3 ammmonia into a gas flow-through device.

Anion transfer processes at a liquid|liquid interface were studied with an interdigitated gold band array electrode. The organic phase, 4-(3-phenylpropyl)-pyridine containing Co(II)phthalocyanine, was immobilised as random droplets at the electrode surface and then immersed into aqueous electrolyte. Oxidation of Co(II)phthalocyanine at the generator electrode was shown to be associated with anion transfer from the aqueous into the organic phase. The corresponding back reduction at the collector electrode with anion expulsion was delayed by the anion/cation diffusion time across the interelectrode gap. A working curve based on a finite difference numerical simulation model was employed to estimate the apparent diffusion coefficients for anions in the organic phase (PF6−

Microbial fuel cells (MFCs) represent one of the most attractive and eco-friendly technologies that convert chemical bond energy derived from organic matter into electrical power by microbial catabolic activity. This paper presents the use of a H-type MFC involving a novel NAR-2 bacterial consortium consisting of Citrobacter sp. A1, Enterobacter sp. L17 and Enterococcus sp. C1 to produce electricity whilst simultaneously decolourising acid red 27 (AR27) as a model dye, which is also known as amaranth. In this setup, the dye AR27 is mixed with modified P5 medium (2.5 g/L glucose and 5.0 g/L nutrient broth) in the anode compartment, whilst phosphate buffer solution (PBS) pH 7 serves as a catholyte in the cathode compartment. After several electrochemical analyses, the open circuit voltage (OCV) for 0.3 g/L AR27 with 24-h retention time at 30 °C was recorded as 0.950 V, whereas (93 %) decolourisation was achieved in 220-min operation. The maximum power density was reached after 48 h of operation with an external load of 300 Ω. Scanning electron microscopy (SEM) analysis revealed the surface morphology of the anode and the bacterial adhesion onto the electrode surface. The results of this study indicate that the decolourisation of AR27 dye and electrical power generation was successfully achieved in a MFC operated by a bacterial consortium. The consortium of bacteria was able to utilise AR27 in a short retention time as an electron acceptor and to shuttle the electrons to the anode surface for bioelectricity generation.

A double-chambered membrane microbial fuel cell (MFC) was constructed to investigate the potential use of natural microflora anaerobic palm oil mill effluent (POME) sludge and pure culture bacteria isolated from anaerobic POME sludge as inoculum for electricity generation. Sterilized final discharge POME was used as the substrate with no addition of nutrients. MFC operation using natural microflora anaerobic POME sludge showed a maximum power density and current density of 85.11mW/m(2) and 91.12mA/m(2) respectively. Bacterial identification using 16S rRNA analysis of the pure culture isolated from the biofilm on the anode MFC was identified as Pseudomonas aeruginosa strain ZH1. The electricity generated in MFC using P. aeruginosa strain ZH1 showed maximum power density and current density of 451.26mW/m(2) and 654.90mA/m(2) respectively which were five times higher in power density and seven times higher in current density compared to that of MFC using anaerobic POME sludge.

The aim of this study was to isolate and characterize psychrotrophic bacteria resistant to antibiotic and metals from cold samples of refrigerated spoiled food and ice. Two isolates named H and F were successfully isolated from samples incubated at 10°C and 4°C, respectively. Both isolates were able to grow at 4°C, 10°C, 20°C and 30°C and exhibited multidrug resistance to antibiotics (chloramphenicol, ampicillin, tetracycline and kanamycin). Bacteria H and F were then further tested for their resistance to metal ions such as Cd 2+ , Zn 2+, Cr 6+ and As 3+ at concentrations ranging from 0-10 mM. The results of the test revealed that the minimum inhibitory concentration (MIC) for isolate H was determined at 2 mM for all the metal ions. By comparison, isolate F was highly resistant to Cr 6+, Cd 2+ andZn 2+ with MIC of 10 mM for these cations, while MIC for As 3+ was 4 mM. The results of comparing 16S rRNA gens demonstrated that isolate F has 98% identity match with Bacillus sp . This strain could be used as a model microbial strain to understand the mechanisms of metal resistance and as a source of psychrotrophic enzymes with potential application for bioremediation of heavy metals in cold environments.

The screening of cultivation conditions for the highest hydrogen production using mixed microflora was performed in serum bottles. The fermentation conditions were studied for temperature, inoculum size, and initial pH, and it shows the significant effect of these factors in enhancing the biohydrogen production. The optimum condition was found at 60 °C with initial pH of 7, and the percentage of inoculum added to POME medium was at 30:70 % (v/v). In the following experiment, batch thermophilic hydrogen fermentation was conducted in 0.5 L medium using the optimum conditions, which were run for 30 h. The highest yield of 4.85 mol H2/mol glucose was achieved when the fermentation was started with 4 g/L initial glucose concentration.