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Date biomass is a carbon-rich renewable resource that can be considered a potential carbon-rich substrate for energy generation over anaerobic digestion (AD). However, due to its complex nature, appropriate pretreatment is necessary to achieve a higher methane yield. Hence, the current study was envisioned to evaluate the influence of three different pretreatment strategies, namely acid, alkali, and hydrothermal pretreatment on biochemical methane potential (BMP) of seven diverse sorts of Algerian date biomass, namely Pedicels, Fibrilium, Petiole, Fruit bunch, Spath, Palm, and its mixture. Among all the pretreatment conditions, alkaline pretreatment highly influenced the lignin composition of date biomass and showed higher BMP. Among all sorts of biomass, higher BMP was detected through Palm as 295.9 mL CH4/g-TS, whereas the lowest BMP values were recorded with Petiole as 226.74 mL CH4/g-TS. Among all the experimental variations, ammonium pretreated Palm biomass documented the highest substrate conversion efficiency (63.80%), which correlates well with the observed higher BMP values. Nevertheless, there was a very marginal improvement in BMP detected in the case of other pretreatment strategies compared to alkaline pretreatment. This might be due to the efficacy of the applied pretreatment method on delignification of date biomass.

This review focuses on the current developments and new insights in the field of dark fermentation technologies using wastewater as carbon and nutrient source. It has begun with the type of wastewaters (sugar rich, toxic and industrial) employed in the H 2 production and their production performances with pure (or) mixed microbiota as seeding source in the batch reactors. Secondly, well-documented continuous system performances and their failure reasons were examined along with the enhancement possibilities in ways of strategies. A SWOT analysis has been performed to validate the strength and weakness of the continuous systems towards its industrialization and possible scheme of the integration methods have been illustrated. Additionally, an outlook has been provided with enlightening the remedies for its success. Moreover, the practical perspectives of the continuous systems are highlighted and challenges towards scale up are mentioned. Finally, the possible integrative approaches along with continuous systems towards the bioH 2 technologies implementation are enlightened.

The present fossil fuel-based energy sector has led to significant industrial growth. On the other hand, the dependence on fossil fuels leads to adverse impact on the environment through releases of greenhouse gases. In this scenario, one possible substitute is biohydrogen, an eco-friendly energy carrier as high-energy produces. The substrates rich in organic compounds like organic waste/wastewater are very useful for improved hydrogen generation through the dark fermentation. Thus, this review article, initially, the status of biohydrogen production from organic waste and various strategies to enhance the process efficiency are concisely discussed. Then, the practical confines of biohydrogen processes are thoroughly discussed. Also, alternate routes such as multiple process integration approach by adopting biorefinery concept to increase overall process efficacy are considered to address industrial-level applications. To conclude, future perspectives besides with possible ways of transforming dark fermentation effluent to biofuels and biochemicals, which leads to circular bioeconomy, are discussed.

Microbial electrolysis cell (MEC) is a potentially attractive green technology to tackle the global warming and energy crisis, which employs electrochemically active bacteria to convert organic matter into hydrogen or a wide range of chemicals, such as methane, acetate, hydrogen peroxide, ethanol, and formic acid, without causing environmental pollution. Until now, probably the cleanest and the most efficient method of producing hydrogen has been MEC. However, this technology is still in its infancy period and poses various challenges towards up-scaling and widespread applications, such as such as lower hydrogen production rate (HPR), high internal resistance, complicated architecture, and expensive materials. New advances are needed in biofilm engineering, materials for electrodes and reactor configuration for successful real-world application of this technology. Thus, the present review deals with development of practical MEC technology and includes the following sections: firstly a general introduction to MECs; their operating principles, thermodynamics of MEC, and energy or voltage losses in the MEC system were provided. Followed by a section on the critical factors affecting MEC performance; microorganisms, anode, cathode, membrane or separator, fuel sources, the state-of-art MECs designs, other key operational factors, and its potential application in microbial production of value added products are discussed in detail. Afterwards, current challenges involved in developing practical MEC systems are highlighted, and outlooks for future development are also suggested. The review aims to assist researcher and engineers to gain fundamental understandings of MEC, and it also provides several future research directions and a road map on how to overcome the barriers, so the MEC technology can be further advanced and applied in larger scale.

The present study investigates the potential of anti-urolithiatic activity of ethanolic extract of Taxillus tomentosus plant (EETT). Urolithiasis was induced by feeding the 0.75% of Ethylene glycol (EG) and 2% of Ammonium chloride (AC) in drinking water along with the normal feed in male wistar rats and then the anti-urolithiatic activity of EETT was evaluated. Acute toxicity study was conducted by LD 50 cutoff dose of 2000mg/kg body weight (BW), indicates that the drug to be much safer and 1/10 th (200mg/kg BW) and 1/5 th (400mg/kg BW) of LD 50 doses were selected for study. Serum and urine samples were analyzed for knowing the concentration of creatinine, calcium, urea, uric acid, oxalates and during the entire study, urolithiatic animals showed significantly high concentrations than normal animals. The EETT (200mg/kg BW and 400mg/kg BW) was showed good response to antiurolithiatic activity when compared to the standard drug cystone (CST). Keywords: a nti-urolithiatic activity, taxillus tomentosus, ethylene glyco, ammonium chloride, cystone.

Hydrogen gas has tremendous potential as an environmentally acceptable energy carrier for vehicles. A cutting edge technology called a microbial electrolysis cell (MEC) can achieve sustainable and clean hydrogen production from a wide range of renewable biomass and wastewaters. Enhancing the hydrogen production rate and lowering the energy input are the main challenges of MEC technology. MEC reactor design is one of the crucial factors which directly influence on hydrogen and current production rate in MECs. The rector design is also a key factor to up-scaling. Traditional MEC designs incorporated membranes, but it was recently shown that membrane-free designs can lead to both high hydrogen recoveries and production rates. Since then multiple studies have developed reactors that operate without membranes. This review provides a brief overview of recent advances in research on scalable MEC reactor design and configurations.

Dark fermentation is a technically feasible technology for achieving carbon dioxide-free hydrogen production. This review presents the current findings on continuous hydrogen production using dark fermentation. Several operational strategies and reactor configurations have been suggested. The formation of attached mixed-culture microorganisms is a typical prerequisite for achieving high production rate, hydrogen yield, and resilience. To date, fixed-bed reactors and dynamic membrane bioreactors yielded higher biohydrogen performance than other configurations. The symbiosis between H2-producing bacteria and biofilm-forming bacteria was essential to avoid washout and maintain the high loading rates and hydrogenic metabolic flux. Recent research has initiated a more in-depth comparison of microbial community changes during dark fermentation, primarily with computational science techniques based on 16S rRNA gene sequencing investigations. Future techno-economic analysis of dark fermentative biohydrogen production and perspectives on unraveling mitigation mechanisms induced by attached microorganisms in dark fermentation processes are further discussed.

Date biomass is a renewable natural resource since it can be substituted in a comparatively shorter period. Hence it is considered as a possible feedstock for bioenergy motivations through anaerobic digestion (AD). Despite the fact AD is a fully demonstrated technology, the use of new feedstock necessitates detailed investigation. Worldwide several researchers are evaluating methane yield short of paying much consideration to the source type and structural and elemental composition of biomass. Hence, the current study was intended to relate methane yield to those two structural and chemical composition of biomass. In this sense, biochemical methane potential (BMP) for different date biomass, namely Pedicels, Fibrilium, Petiole, Fruit bunch, Spath, Palm, and a mixture of all biomass samples was tested for 30 days. Among all the experimental variations, higher productivity was observed with Palm as 72.60 mL CH4/g VS/days, followed by Spath (66.61 mL CH4/g VS/days), Mixed biomass (64.57 mL CH4/g VS/days), Fruit bunch (64.34 mL CH4/g VS/days), Pedicels (59.06 mL CH4/g VS/days), Fibrilium (57.42 mL CH4/g VS/days), and Petiole (41.17 mL CH4/g VS/days). From the experimental results, it can be concluded that among all the biomass samples, Palm is the best substrate for higher methane production. However, the remaining experimental conditions produced methane yield was comparatively low. This might be due to the composite nature of the substrate with lignin as an insoluble fraction. Hence, Pedicels, Fibrilium, and Petiole biomasses cannot be recommended as a substrate for biogas production without appropriate pretreatment.

In recent years, bioelectrochemical hybrid technology has emerged as an alternative energy conversion device for bioelectricity generation with concurrent waste remediation. The major attractions of this bioelectrochemical technology are eco-friendly nature, energy-saving, and energy transformation with reduced sludge generation. A wide variety of substrates, including complex wastewater, can be employed as a potential substrate to operate the bioelectrochemical cells (BEC). Hence, microbial electro-remediation technologies are aimed towards the enhancement of the metabolic activity of electrochemically active biocatalyst by supplying organic/inorganic nutrients, electron acceptors, or donors, thus stimulating oxidation or reduction of contaminants. In this regard, BEC has gained much attention, in which the control environment is feasible by means of electrical current/voltage that serves as a donor or acceptor for hazardous waste remediation. In the present review, we mainly emphasize the developments and advancements of microbial electro-remediation technologies in the direction of complex hazardous waste remediation. We reviewed and discussed various BEC mediated complex pollutants remediation (ex: aromatics, dye, nitrogen compounds, heavy metals etc.) and its limitations. In conclusion, the future perspectives in the BEC for bioenergy generation with concurrent waste remediation are proposed through numerous aspects and approaches to afford clean energy and the environment.

Since the last century, the search for clean and renewable energy is going on. This process will continue until there is a stable solution available as an alternative to fossil fuels. Several energy-producing products arise from photosynthetic-organisms like biofuel, bioelectricity, and there are various methods also available for the extraction of these products. Microbial fuel cells (MFCs) are energy transducers which convert organic matter directly into electricity, through the process of anaerobic respiration of microorganisms. Now a day’s researchers have taken as a challenge to use algae along with the bacterial communities to provide an organic carbon fuel source for the MFCs. This paper describes the potential application of algal biomass in the field of bioelectricity. Till now, many scientific experiments conducted all around the world to demonstrate how well efficient is this green photosynthetic organism capable of producing electricity along with its other applications like biofuel, demand in the food industry, and much more. The present manuscript aimed to provide an overview of the potential use of algae as a biocatalyst in MFCs. Further, this article also provides the current status of numerous countries which are excelled in the field of bioelectricity generation.

Biohydrogen (H2) production from renewable wastewater signifies a sustainable alternative to the fossil fuel-based economy. H2 is deemed to be the futuristic energy carrier with high-energy yield. This communication specifically addresses H2 production through wastewater remediation. A comprehensive emphasis was made on the fermentative routes, viz., light-driven and light-independent processes, encompassing wastewater and mixed culture application as the focal point. Important process parameters that have a critical role on the process efficiency were elaborated. Some of the persistent limitations encountered during the process operation were delineated. Stress was made on the pertinent discussion on biocatalyst pretreatment methods in the context of mixed culture wastewater usage. Reported strategies to overcome the limitations were discussed to make the process economically viable, especially for large-scale applications.

Microbial electrolysis cells (MECs) are generally regarded as a promising future technology for manufacturing green hydrogen from organic material present in wastewaters and other renewable energy sources. However, the development of inexpensive and high-efficient cathode catalyst is the most critical challenge for MECs to become a commercialized H2 production technology. In this study, a non-noble metal electroformed Ni mesh cathode alternatives to typical cathode material (Pt/CC) was intensively examined in a single-chamber membrane-free MEC. To the best of our knowledge, the use of electroformed Ni mesh as the MEC cathode catalyst has not been reported so far. The MEC was operated in fed-batch mode and the performance of the Ni mesh cathode was compared with that of Pt/CC cathode in terms of columbic efficiencies (75 ± 4% vs. 72.7 ± 1%), overall hydrogen recovery (89.3 ± 4% vs. 90.9 ± 3%), overall energy efficiency (62.9 ± 5% vs. 69.1 ± 2%), the maximum volumetric hydrogen production rate (4.18 ± 1 m3 H2/m3 d vs. 4.25 ± 1 m3 H2/m3 d), volumetric current density (312 ± 9 A/m3 vs. 314 ± 5 A/m3). The obtained results in this study highlight the great potential of using the electroformed Ni mesh catalysts as a viable cathode material for hydrogen production in MECs.

The current fossil fuel-based generation of energy has led to large-scale industrial development. However, the reliance on fossil fuels leads to the significant depletion of natural resources of buried combustible geologic deposits and to negative effects on the global climate with emissions of greenhouse gases. Accordingly, enormous efforts are directed to transition from fossil fuels to nonpolluting and renewable energy sources. One potential alternative is biohydrogen (H2), a clean energy carrier with high-energy yields; upon the combustion of H2, H2O is the only major by-product. In recent decades, the attractive and renewable characteristics of H2 led us to develop a variety of biological routes for the production of H2. Based on the mode of H2 generation, the biological routes for H2 production are categorized into four groups: photobiological fermentation, anaerobic fermentation, enzymatic and microbial electrolysis, and a combination of these processes. Thus, this review primarily focuses on the evaluation of the biological routes for the production of H2. In particular, we assess the efficiency and feasibility of these bioprocesses with respect to the factors that affect operations, and we delineate the limitations. Additionally, alternative options such as bioaugmentation, multiple process integration, and microbial electrolysis to improve process efficiency are discussed to address industrial-level applications.

Bacteria are ubiquitous and it is reported that among them surface attached bacteria is over 99% population wise. However, the attached growth or sessile life of bacteria poses a different problem in human life. Chronic infection, contamination in food industries and biofouling in industrial materials are serious challenges which need to overcome. It is imperative to understand the bacterial adhesion and subsequent biofilm development to study biofilm-associated deceases and mitigating biofouling. In the present book chapter, the technical know-how of bacterial biofilm development has been depicted. A thorough understanding of the fundamental principles of bacterial biofilm would help to perceive new aspects of biofouling and pathogenicity associated with biofilm and how fouling could be controlled and contamination can be prevented. In this chapter, parameters affecting biofilm formation, the role of extracellular polymeric substances (EPS) and eDNA, the factors of materials which influence attachment and detachment of biofilm have been clearly described. The present chapter highlights the major factors involved in the signaling system to promote Biofilm formation.

The imminent energy crisis due to reserved fossil fuel and global warming due to greenhouse gas emission warrant the necessity for environmentally friendly sources of energy. Fossil fuels adversely affect the nature due to the release of CO2 into the environment (Venkata Mohan et al. 2011; Venkateswar Reddy et al. 2011a; Kadier et al. 2016a, b). Hence the consumption of fossil fuels based energy sources has harshly threatened human life through its drastic consequences, such as global warming and environmental pollution. As a result, in the present global energy scenario, searching for other energy resources is necessary (Kadier et al. 2015; Chandrasekhar et al. 2015a; Venkata Mohan and Pandey 2013). Last few years, several researchers around the world have made remarkable efforts to find a solution for this energy crisis (Venkata Mohan et al. 2013). In this scenario, fuel cells are a unique addition to the list of alternative energy sources having a negligible CO2 emission. Production of electricity using microorganisms was firstly reported early in the last century (Potter 1911). Microbial fuel cell (MFC) have been considered as a bio-based reactor that modifies the chemical energy of substrate into electrical energy through biocatalytic action of exoelectrogenic microorganisms under anaerobic circumstances over sequences of metabolic reactions (Kondaveeti and Min 2015; Chandrasekhar et al. 2015b). MFC technology signifies an innovative approach of using microorganisms for bioelectricity generation by the oxidation of organic substrate varied from the synthetic substrate such as acetate, glucose to a complex mixture of the organic substrate including food, dairy, distillery, animal and domestic wastewater. In recent years, MFC technology has been developing as one of the popular wastewater treatment based technology to deliver clean water and green energy (Venkata Mohan and Chandrasekhar 2011a, b; Pant et al. 2012; Pandit et al. 2012a, b; Chandrasekhar et al. 2015b). These MFCs overtook other conventional technologies such as an aerated lagoon and anaerobic digester (Logan 2008). Unlike traditional fuel cells, one step conversion of carbon-rich organic waste as a potential substrate to generate bioelectricity in MFCs ensures better conversion capability. MFCs can evade extra gas treatment process due to its CO2 rich off-gas. Moreover, single chambered or open-air cathode MFCs do not need any external energy input. Hence, it can be advantageous for extensive application in locations lacking electrical amenities (Stams et al. 2006). This chapter stretches an account of the basic principles involved in the working of MFCs and the key applications, challenges and future scope of MFC technology, as it stands today.

Biofouling is a serious drawback found in technological tools exposed in an aqueous medium; it plays a significant role in selecting suitable materials used in a different industrial application like food processing industry, shipping yards, water treatment and desalting tools; consequently, it has huge impact viability and economic feasibility of those systems. Biofouling includes organic fouling, particulate/colloidal fouling and fouling occurred due to microbial/biological entities. The present chapters dealt about bacterial mediated biofouling. Bacterial-mediated biofouling represents the “Achilles heel” due to bacteria’s ability to multiply over time; this type of biofouling is potentially more dangerous. An iota of living cells attached to the surface can grow and form biofilms using the dissolve organic substances in the water. Bacterial biofouling is recently gaining much interest due to it’s severe economic and environmental adverse effects. In the present book chapter, the different types of biofouling and their causes have been highlighted. A thorough understanding of the fundamental principles of biofilm generation would help to prevent biofouling. Basics of biofilm development causing fouling and the factors affecting fouling have been depicted. A short discussion about the means to mitigate biofouling has been provided. The present chapters also described different anti-biofouling strategies adapted to in various industrial tools. A brief description of the influence of biofouling in water treatment, food processing, and biomedical devices has been provided. Advantages and disadvantages of bacterial-mediated biofouling have been discussed.

In this paper we present the novel idea of computing near the edge of IOT architecture which enhances the inherent efficiency while computing complex applications. This concept is termed as mist computing. We believe this computing will bring about an massive revolution in future computing technologies. instead of thrusting the control responsibility to gateways while data transmission the control is decentralised to end nodes which decrease the communicational delay of the network thereby increasing the throughput.

The present study evaluates the feasibility of increased power generation in microbial fuel cells (MFCs) coupled with acid elutriation fermentation. Raw piggery waste (RPW) and acid elutriation effluents (AEE) of piggery waste were used to generate bioelectricity in single-chambered air-cathode MFCs. RPW-fed MFCs exhibited stable performance after 12-days of operation, generating 540mV of open circuit voltage (OCV). RPW fed-MFCs displayed peak potential and maximal power density (PDmax) of 0.364V and 192mW/m2 with 980Ω external resistance (Rext), respectively. AEE-fed MFCs documented 818mV of maximum OCV. Furthermore, the peak potential and PDmax of 0.329V and 1553mW/m2 were generated with 100Ω Rext, respectively. RPW and AEE-fed MFCs exhibited 84% and 93% substrate removal efficiency, respectively. These findings suggest that a two-stage process including acid elutriation reactor asa pre-fermentation and MFCs greatly enhances substrate removal and electricity generation from piggery waste.

Microbial electrolysis cells (MECs) are perceived as a potential and promising innovative biotechnological tool that can convert carbon-rich waste biomass or wastewater into hydrogen (H

A novel bio-electrohydrolysis system (BEH) based on self-inducing electrogenic activity was designed as pretreatment device to enhance biohydrogen (H2) production efficiency from food waste. Two-stage hybrid operation with hydrolysis in the initial stage and acidogenic fermentation of the resulting hydrolysate (after hydrolysis) for H2 production in the second stage was evaluated. Application of variable external resistances viz., 10 Ω, 100 Ω, 1000 Ω and closed circuit (CC) influenced the hydrolysis of substrate in BEH system and hydrogen production in acidogenic reactor compared to control. Pretreated substrate at 100 Ω documented higher H2 production (1.05 l) than 10 Ω (0.93 l), CC (0.91 l), 1000 Ω (0.88 l) and control operation (0.68 l). Comparatively, 10 Ω documented higher substrate degradation (53.4%) followed by CC (52.42%), 100 Ω (49.51%), 1000 Ω (47.57%) and control (43.68%). Voltammetric profiles were in agreement with the observed bio-electrohydrolysis and H2 production efficiency.

A novel bio-electrohydrolysis system (BEH) based on self-inducing electrogenic activity was designed as a pretreatment device to enhance biohydrogen (H2) production efficiency of food waste. Experimental strategy involved two-stage integrated/hybrid operation with hydrolysis in initial stage followed by acidogenic fermentation for H2 production in second stage. After pre-treatment, catabolized food waste from control (anaerobic) and BEH (closed circuit mode of operation) system was used as substrate in a separate bioreactor to evaluate H2 production in dark-fermentation process. Pretreated-waste from BEH showed higher H2 production (29.12 ml/h; 24th h) than control (26.75 ml/h; 16th h). Higher cumulative H2 production and maximum substrate degradation were also noticed with BEH-pretreated substrate (CHP, 0.91 l; COD, 52.42%) than control (CHP, 0.68 l; COD, 43.68%). Under closed circuitry, anode served as an alternative electron acceptor promoting biotransformation of complex organics to simpler molecules through catabolism.

A two-chambered microbial fuel cell (MFC), which can function on the self-driven bioelectrogenic activity operated on anaerobically digested distillery waste (ADDW) i.e. wastewater post anaerobic digestion was designed and fabricated in the laboratory. MFC was evaluated for production of bioelectricity with a simultaneous reduction in the carbon content. Using a surface response methodology with a Box-Behnken design (BBD), operating conditions such as the concentration of antifoam, pH, and resistance were optimized and it was found that the pH and resistance were optimum at 8.3 and 1000 0, respectively with no antifoam in the system. Under optimum conditions, 31.49 Wm-3 was generated, and 60.78 +/- 0.95% total organic carbon was degraded. We revealed that the fermentative bacteria generated organic acids mainly acetate from dextrose present in ADDW and electrogenic bacteria oxidized acetate in a successive manner to generate electrons, which was confirmed by gas chromatography. The development of biofilm analyzed by scanning electron microscope (SEM) was found to be crucial in the transfer of electrons directly to the anode and was confirmed by cyclic voltammetry experiments. Identification of bacteria from biofilm by both culture and denaturing gradient gel electrophoresis methods found bacteria belonging to phylum Firmicutes and gamma-proteobacteria. The study of successive nature of bacterial metabolism to generate electricity could play an important role in the production of electricity in a continuous mode of operation using MFCs fed with ADDW for further reduction of carbon content post anaerobic digestion for the benefit for the environment. Thus MFC can be used as a complementary technology to anaerobic digestion. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Water and energy securities are emerging as increasingly important and vital issues for today’s world. Therefore, the field of wastewater management and alternative energy is one of the most unexplored fields of Biotechnology and Science. Microbial fuel cell (MFC) is emerging as a modern wastewater treatment technology which converts chemical energy stored in the bonds of organic matter present in wastewater directly into electricity using electrogenic bacteria as a catalyst, without causing environmental pollution. In this chapter, the technical know-how of MFC and biocatalyst has been depicted. A thorough understanding of the fundamental principles of microbial fuel cells would help to perceive new aspects of bioenergy conversions and how such systems could be integrated with the present energy generation systems to maximize the energy recovery. In this respect, MFCs show promise to treat wastewater with simultaneous production of renewable energy. In this chapter, the theories underlying the electron transfer mechanisms, the biochemistry and the microbiology involved, and the material characteristics of anode, cathode, and the separator have been clearly described. This chapter highlights the major factors involved toward the improvement bioelectricity production processes. Advance in the design of MFC Technology and the economy of the process are also included.

The field of wastewater management and alternative energy are one of the most unexplored fields of environmental biotechnology. The biomethane is considered as renewable natural gas which can be derived from organic waste and sewage treatment. In recent past biomethane is emerging as a promising gaseous fuel utilized in a cogeneration or trigeneration power plant. Biomethane usually produced through anaerobic digestion in oxygen-deficient environment where a series of microorganisms convert the complex waste to biogas via liquefaction through a cascade of enzymes. Biomethane produced in anaerobic digester can be utilized for decentralized power generation, and additionally revenue can be gained in the form of a CO2 credits and/or other greenhouse gas emission credits. In the present book chapter, the technical know-how of anaerobic digestion and biocatalyst associated with digester has been depicted. A thorough understanding of the fundamental principles of anaerobic digestion would help to perceive new aspects of bioenergy conversions. The book chapter highlights the concise of biochemistry for biomethane production as well as important major factors involved in the process toward the realization of a stable biomethane-based economy. Successful application of anaerobic digester was found in pilot-scale potential wastewater treatment along with renewable energy production. The proper configuration anaerobic digester and efficiently pretreated “feedstock” are key to maximize the production of methane. Therefore, basics of reactor design designs based on process economy have been discussed.

Remediation of real-field petroleum sludge was studied under self-induced electrogenic microenvironment with the function of variable organic loads (OLs) in bio-electrochemical treatment (BET) systems. Operation under various OLs documented marked influence on both electrogenic activity and remediation efficiency. Both total petroleum hydrocarbons (TPH) and its aromatic fraction documented higher removal with OL4 operation followed by OL3, OL2, OL1 and control. Self-induced biopotential and associated multiple bio-electrocatalytic reactions during BET operation facilitated biotransformation of higher ring aromatics (5–6) to lower ring aromatic (2–3) compounds. Asphaltenes and NSO fractions showed negligible removal during BET operation. Higher electrogenic activity was recorded at OL1 (343 mV; 53.11 mW/m 2 , 100 Ω) compared to other three OLs operation. Bioaugmentation to anodic microflora with anaerobic culture documented enhanced electrogenic activity at OL4 operation. Voltammetric profiles, Tafel analysis and VFA generation were in agreement with the observed power generation and degradation efficiency.

The fluorescence quenching studies of carboxamide namely (E)-N-(3-Chlorophenyl)-2-(3,4,5-trimethoxybenzylideneamino)-4,5,6,7 tetrahydrobenzo[b]thiophene-3-carboxamide [ENCTTTC] by aniline and carbon tetrachloride in six different solvents namely toluene, cyclohexane, n-hexane, n-heptane, n-decane and n-pentane have been carried out at room temperature with a view to understand the quenching mechanisms. The Stern–Volmer (S–V) plots have been found to be non-linear with a positive deviation for all the solvents studied. In order to interpret these results we have invoked the ground state complex formation and sphere of action static quenching models. Using these models various quenching rate parameters have been determined. The magnitudes of these parameters suggest that sphere of action static quenching model agrees well with the experimental results. Hence the positive deviation is attributed to the static and dynamic quenching. Further, with the use of Finite Sink approximation model, it was possible to check these bimolecular reactions as diffusion-limited and to estimate independently distance parameter R ′ and mutual diffusion coefficient D . Finally an effort has been made to correlate the values of R ′ and D with the values of the encounter distance R and the mutual coefficient D determined using the Edward's empirical relation and Stokes Einstein relation.

Bioremediation of selected endocrine disrupting compounds (EDCs)/estrogens viz. estriol (E3) and ethynylestradiol (EE2) was evaluated in bio-electrochemical treatment (BET) system with simultaneous power generation. Estrogens supplementation along with wastewater documented enhanced electrogenic activity indicating their function in electron transfer between biocatalyst and anode as electron shuttler. EE2 addition showed more positive impact on the electrogenic activity compared to E3 supplementation. Higher estrogen concentration showed inhibitory effect on the BET performance. Poising potential during start up phase showed a marginal influence on the power output. The electrons generated during substrate degradation might have been utilized for the EDCs break down. Fuel cell behavior and anodic oxidation potential supported the observed electrogenic activity with the function of estrogens removal. Voltammetric profiles, dehydrogenase and phosphatase enzyme activities were also found to be in agreement with the power generation, electron discharge and estrogens removal.

The effect of soil concentration on the aerobic degradation of real-field petroleum sludge was studied in slurry phase reactor. Total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs) showed effective removal but found to depend on the soil concentration. Aromatic fraction (48.12%) documented effective degradation compared to aliphatics (47.31%), NSO (28.69%) and asphaltenes (26.66%). PAHs profile showed efficient degradation of twelve individual aromatic compounds where lower ring compounds showed relatively higher degradation efficiency compared to the higher ring compounds. The redox behaviour and dehydrogenase activity showed a linear increment with the degradation pattern. Microbial community composition and changes during bioremediation were studied using denaturing gradient gel electrophoresis (DGGE). Among the 12 organisms identified, Proteobacteria was found to be dominant representing 50% of the total population (25% of γ-proteobacteria; 16.6% of β-proteobacteria; 8.3% of α-proteobacteria), while 33.3% were of uncultured bacteria and 16.6% were of firmicutes.

Functional role of biomolecules viz., carbohydrates and proteins on acidogenic biohydrogen (H2) production was studied through the treatment of canteen based composite food waste. The performance was evaluated in an anaerobic sequencing batch reactor (AnSBR) at pH 6 with five variable organic loading conditions (OLR1, 0.854; OLR2, 1.69; OLR3, 3.38; OLR4, 6.54 and OLR5, 9.85 kg COD/m3-day). Experimental data depicted the feasibility of H2 production from the stabilization of food waste and was found to depend on the substrate load. Among the five loading conditions studied, OLR4 documented maximum H2 production (69.95 mmol), while higher substrate degradation (3.99 kg COD/m3-day) was observed with OLR5. Specific hydrogen yield (SHY) vary with the removal of different biomolecules and was found to decrease with increase in the OLR. Maximum SHY was observed with hexose removal at OLR1 (139.24 mol/kg HexoseR at 24 h), followed by pentoses (OLR1, 108.26 mol/kg PentoseR at 48 h), proteins (OLR1, 109.71 mol/kg ProteinR at 48 h) and total carbohydrates (OLR1, 58.31 mol/kg CHOR at 24 h). Proteins present in wastewater helped to maintain the buffering capacity but also enhanced the H2 production by supplying readily available organic nitrogen to the consortia. Along with carbohydrates and proteins, total solids also registered good removal.

Bio-electrochemical treatment (BET) documented effective degradation of real field petroleum sludge over the conventional anaerobic treatment (AnT). BET (41.08%) operation showed enhanced total petroleum hydrocarbons (TPH) removal over AnT (20.72%). Aromatic fraction visualized higher removal (75.54%) compared to other TPH fractions viz., aliphatics, asphaltenes and NSO (nitrogen, sulfur and oxygen) during BET operation. Higher ring aromatics (5-6) documented easy degradation in BET, while AnT was limited to lower ring (2-3) compounds. Voltammetric analysis evidenced simultaneous redox behavior during BET operation due to presence of graphite electrode as electron acceptor, while AnT showed extended reduction behavior only. Self-induced primary and secondary oxidation reactions and capacitive-deionization might have enhanced the degradation capability of BET. BET documented higher charge/capacitance (2810 mJ/1120 mF) than AnT (450 mJ/180 mF). Power output corroborated well with observed results supporting BET performance as fuel cell. Electrodes offer a potential alternative electron acceptor for promoting the degradation of organic contaminants.

The essential oil of Premna latifolia Roxb. was obtained by hydrodistillation of fresh leaves of the plant having an oil yield of 0.05%, both non-polar and essential oil were analysed by GC and GC-MS. Hexane fraction of the leaves of P. latifolia was transesterified and analysed by GC and GC-MS, 40 non-polar components were identified comprising 89.3%. The most abundant fatty acid constituents were hexadecanoic acid (25.04%), 8,11,14-docosatrienoic acid (13.62%), octadecanoic acid (6.82%), 9,12-octadecadienoic acid (4.19%) and 29 components were investigated in the essential oil which comprises 78.1%. The most abundant oil constituents were 1-octen-3-ol (35.69%), terpendiol II (7.19%), δ-guaiene (7.49%) 2-undecanone (4.80%) and α-pinene (3.27%). Different extracts were also tested against polyphagous crop pest Spodoptera litura for antifeedant activity. Essential oil showed maximum growth reduction of 56.83% followed by chloroform extract of 43.93%.

A novel solid state bio-electrofermentation system (SBES), which can function on the self-driven bioelectrogenic activity was designed and fabricated in the laboratory. SBES was operated with food waste as substrate and evaluated for simultaneous production of electrofuels viz., bioelectricity, biohydrogen (H2) and bioethanol. The system illustrated maximum open circuit voltage and power density of 443 mV and 162.4 mW/m(2), respectively on 9 th day of operation while higher H2 production rate (21.9 ml/h) was observed on 19th day of operation. SBES system also documented 4.85% w/v bioethanol production on 20th day of operation. The analysis of end products confirmed that H2 production could be generally attributed to a mixed acetate/butyrate-type of fermentation. Nevertheless, the presence of additional metabolites in SBES, including formate, lactate, propionate and ethanol, also suggested that other metabolic pathways were active during the process, lowering the conversion of substrate into H2. SBES also documented 72% substrate (COD) removal efficiency along with value added product generation. Continuous evolution of volatile fatty acids as intermediary metabolites resulted in pH drop and depicted its negative influence on SBES performance. Bio-electrocatalytic analysis was carried out to evaluate the redox catalytic capabilities of the biocatalyst. Experimental data illustrated that solid-state fermentation can be effectively integrated in SBES for the production of value added products with the possibility of simultaneous solid waste remediation.

Microbial electrolysis cells (MECs) are a novel technology aiming at producing hydrogen from biomass or wastewater. The collection and preservation of the gas generated in the MECs is the first and most important operation in gas measuring techniques. There are several techniques for the quantitative evaluation of gas production in MECs, such as Owen method, respirometre, and gas bag methods. However, the costs associated with these methods could make MEC technology scale-up expensive and impractical. This work describes evaluation of commonly used biogas measurement techniques and analyses potential errors associated with liquid displacement gas measurement. Inaccuracy mainly due to CO2, and CH4 dilution in displaceable liquids was evaluated by testing solubility of CO2 in 12 different barrier solutions. 95% saturated NaCl (pH 0.5) solution exhibited lower CO2 solubility among the tested solutions. These results indicate that gas production in MECs can be accurately tested using an inexpensive, simple gas metre.

Biohydrogen (H2) production from renewable wastewater signifies a sustainable alternative to a fossil fuel-based economy. H2 is deemed to be the futuristic energy carrier with a high-energy yield. This chapter specifically addresses H2 production through wastewater remediation. A comprehensive emphasis is made on the fermentative routes, namely, light-driven and light-independent processes, encompassing wastewater and mixed culture application as a focal point. Important process parameters that have critical roles on process efficiency are elaborated. Some of the persistent limitations encountered during the process operation are delineated. Stress is made on the pertinent discussion on biocatalyst pretreatment methods in the context of mixed culture wastewater usage. Reported strategies to overcome the limitations are discussed to make the process economically viable, especially for large-scale applications.

The time-resolved laser emission of coumarin 102 was investigated in various aprotic and protic solvents at picosecond resolution by frequency upconversion technique. The spectral shift of the transient emission spectrum is attributed to solvent reorientation and the results are discussed.

The orientational relaxation times (τr) of coumarin 102 and coumarin 138 molecules were measured in ethanol and ethylene glycol solutions at room temperature by transient dichroism technique on picosecond time scales. The experimental data were compared with the calculated values based on Stokes-Einstein-Debye (SED) hydrodynamic model. The results show that the measured values of τr of both the dyes in ethanol reasonally agree with the theoretical ones; but for ethylene glycol solutions, relaxation times are shortened indicating the inadequacy of the SED model for the description of the rotational motions. The results are discussed on the basis of molecular structures of the dyes and intermolecular interactions.

Solid phase microbial fuel cells (SMFC; graphite electrodes; open-air cathode) were designed to evaluate the potential of bioelectricity production by stabilizing composite canteen based food waste. The performance was evaluated with three variable electrode-membrane assemblies. Experimental data depicted feasibility of bioelectricity generation from solid state fermentation of food waste. Distance between the electrodes and presence of proton exchange membrane (PEM) showed significant influence on the power yields. SMFC-B (anode placed 5 cm from cathode-PEM) depicted good power output (463 mV; 170.81 mW/m(2)) followed by SMFC-C (anode placed 5 cm from cathode; without PEM; 398 mV; 53.41 mW/m(2)). SMFC-A (PEM sandwiched between electrodes) recorded lowest performance (258 mV; 41.8 mW/m(2)). Sodium carbonate amendment documented marked improvement in power yields due to improvement in the system buffering capacity. SMFCs operation also documented good substrate degradation (COD, 76%) along with bio-ethanol production. The operation of SMFC mimicked solid-sate fermentation which might lead to sustainable solid waste management practices.

Rotation-free transmission measurements governed by ground-state recovery of coumarin 102, coumarin 138 and coumarin 339 dyes in ethanol solutions were performed for the first time by pump-probe technique using 35 ps pulses of Nd:YAG laser at 355 nm. Recovery of absorption is characterized by simple exponential behaviour with relaxation times of 4.0, 3.7 and 3.0 ns respectively for C 102, C 138 and C 339. These values are comparable to the lifetimes of the first excited singlet states.

SummaryAdult female rats were given the 200th and 10,000th potency of Caulophyllum orally on alternate days for ten days. The vehicle used was 90 per cent. alcohol.The 200th potency brought about a significant increase in ovarian and uterine weight and also in cell height of the endometrium and luminal epithelium. Increased mitotic division was also discernible. Simultaneously the stromal cells became smaller in size and exhibited retardation in mitotic division.In addition, the 200th potency treated groups showed marked retardation in the maturation of ova, with the number of maturing ova minimized. Increased atresia was noted and a perceptible decrease in the number and diameter of functional corpora lutea. The controls and animals treated with the 10,000th potency of the same drug exhibited only insignificant changes.