Abudukeremu Kadier

A review on bio-electrochemical systems (BESs) for the syngas and value added biochemicals production

Bio-electrochemical systems (BESs) are the microbial systems which are employed to produce electricity directly from organic wastes along with some valuable chemicals production such as medium chain fatty acids; acetate, butyrate and alcohols. In this review, recent updates about value-added chemicals production concomitantly with the production of gaseous fuels like hydrogen and methane which are considered as cleaner for the environment have been addressed. Additionally, the bottlenecks associated with the conversion rates, lower yields and other aspects have been mentioned. In spite of its infant stage development, this would be the future trend of energy, biochemicals and electricity production in greener and cleaner pathway with the win-win situation of organic waste remediation. Henceforth, this review intends to summarise and foster the progress made in the BESs and discusses its challenges and outlook on future research advances.

A Terrestrial Single Chamber Microbial Fuel Cell-based Biosensor for Biochemical Oxygen Demand of Synthetic Rice Washed Wastewater.

Microbial fuel cells represent an innovative technology which allow simultaneous waste treatment, electricity production, and environmental monitoring. This study provides a preliminary investigation of the use of terrestrial Single chamber Microbial Fuel Cells (SMFCs) as biosensors. Three cells were created using Andean soil, each one for monitoring a BOD concentration of synthetic washed rice wastewater (SRWW) of 10, 100, and 200 mg/L for SMFC1, SMFC2 and SMFC3, respectively. The results showed transient, exponential, and steady stages in the SMFCs. The maximum open circuit voltage (OCV) peaks were reached during the elapsed time of the transient stages, according to the tested BOD concentrations. A good linearity between OCV and time was observed in the increasing stage. The average OCV in this stage increased independently of the tested concentrations. SMFC1 required less time than SMFC2 to reach the steady stage, suggesting the BOD concentration is an influencing factor in SMFCs, and SMFC3 did not reach it. The OCV ratios were between 40.6–58.8 mV and 18.2–32.9 mV for SMFC1 and SMFC2. The reproducibility of the SMFCs was observed in four and three cycles for SMFC1 and SMFC2, respectively. The presented SMFCs had a good response and reproducibility as biosensor devices, and could be an alternative for environmental monitoring.

Basic Principles of Microbial Fuel Cell: Technical Challenges and Economic Feasibility

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.

Surpassing the current limitations of high purity H2 production in microbial electrolysis cell (MECs): Strategies for inhibiting growth of methanogens

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 (H2) or other value-added chemicals. Undesired methane (CH4) producing H2 sinks, including methanogens, is a serious challenge faced by MECs to achieve high-rate H2 production. Methanogens can consume H2 to produce CH4 in MECs, which has led to a drop of H2 production efficiency, H2 production rate (HPR) and also a low percentage of H2 in the produced biogas. Organized inference related to the interactions of microbes and potential processes has assisted in understanding approaches and concepts for inhibiting the growth of methanogens and profitable scale up design. Thus, here in we review the current developments and also the improvements constituted for the reduction of microbial H2 losses to methanogens. Firstly, the greatest challenge in achieving practical applications of MECs; undesirable microorganisms (methanogens) growth and various studied techniques for eliminating and reducing methanogens activities in MECs were discussed. Additionally, this extensive review also considers prospects for stimulating future research that could help to achieve more information and would provide the focus and path towards MECs as well as their possibilities for simultaneously generating H2 and waste remediation.

Challenges in Microbial Fuel Cell and Future Scope

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.

A comprehensive review on two-stage integrative schemes for the valorization of dark fermentative effluents

Abstract This review provides the alternative routes towards the valorization of dark H2 fermentation effluents that are mainly rich in volatile fatty acids such as acetate and butyrate. Various enhancement and alternative routes such as photo fermentation, anaerobic digestion, utilization of microbial electrochemical systems, and algal system towards the generation of bioenergy and electricity and also for efficient organic matter utilization are highlighted. What is more, various integration schemes and two-stage fermentation for the possible scale up are reviewed. Moreover, recent progress for enhanced performance towards waste stabilization and overall utilization of useful and higher COD present in the organic source into value-added products are extensively discussed.

Phytoremediation and Rhizoremediation: Uptake, Mobilization and Sequestration of Heavy Metals by Plants

Microorganisms residing over the rhizosphere have the capability to catalyse metal uptake in a symbiotic relationship with the roots. This syntrophic relationship enhances the bioavailability of heavy metals and encourages the root adsorption capacity for vital in addition to non-essential metal. It also changes their chemical properties that ultimately have an effect on metal dissolution. Molecular level understanding of the physiological and evolutionary mechanism along with genetics and biochemistry principles underlying the uptake, transportation, translocation and storage of heavy metals (HMs) in model plant species thus allowing alteration to the HM stress can loan much to our comprehension of the fundamental segments of HM metabolism. A lucid understanding of molecular level changes is necessary for plant biotechnologist, regarding changes provoked in plants because of HM stress. It is also helpful to develop stress-resistant cultivars and species with superior phytoremediation capacity through cell and genetic engineering technologies. We hereby summarize the present understanding of HM uptake by plants and also provide a brief study related to their biochemical characteristics of take-up, transport and assortment plus injury and defence mechanism against HM. In this review chapter, we have also focused over the future prospect of research to enhance the discriminate perspective of the basic phytoremediation components specifically rhizoremediation of HMs.

Biohydrogen Production: Integrated Approaches to Improve the Process Efficiency

In recent years, hydrogen (H2) has emerged as a clean and attractive substitute fuel since it can be produced from renewable energy sources. Upon combustion of hydrogen, it generates only water as a major by-product. In hydrogen and fuel cell technology, hydrogen can be applied in fuel cell technology; it produces only water as a major by-product with high energy yield, hold great potential for meeting in a quite unique way by empowering the so-called hydrogen-based economy. To make hydrogen-based economy viable, it is crucial to use renewable resources in place of fossil fuels to produce hydrogen. In this direction, by considering attractive and renewable characteristics of hydrogen led us to improve a variety of biological processes for the production of hydrogen. Nonetheless, commercialization of the biological process depends on improvements in process design along with an understanding of the nature of hydrogen producing communities and process optimization. Thus, this chapter highlights the major factors involved towards the improvement of biohydrogen production processes. Environmental impact of hydrogen as carbon-neutral energy carrier is also discussed. This also includes a technical and economic analysis of the biohydrogen and its role in the proposed hydrogen economy coupled with fuel cell and in transport application. Technological advancements based on hydrogen-based fuel cell designs and process integration approaches are also discussed.

Algae—The Potential Future Fuel: Challenges and Prospects

Algae are single or multicellular photosynthetic organisms that can fix the atmospheric carbon into valuable lipids, proteins, carbohydrates, and fats. These algae are also capable of growing vigorously in different habitats from freshwater to brackish water environments and wastewater streams with nutrient uptake ability. These features make the algae themselves uniquely important in biofuel generation and wastewater treatment process along with CO2 sequestrations without competing with food crop land. The algae can also be used as a substrate for various biofuel generations, bioethanol, bio-butanol, hydrogen, methane, and many commercially valuable products. The applicability and renewability of algal fuel are most promising for the future biotechnological applications. Optimization of algal growth conditions and harvesting technology with desired biofuel generations at low processing cost can make the algae as one of the best sources of energy for future generations. Genetically modified algae which are capable to grow rapidly with generating high cellular lipids and carbohydrate content can be crucial for future energy demand.

Selection of the best barrier solutions for liquid displacement gas collecting metre to prevent gas solubility in microbial electrolysis cells

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.