Microbial Electrochemical Platform: Biofactory with Diverse Applications
01 Jan 2017-pp 35-50
TL;DR: In this paper, the authors draw light upon the multifaceted application of microbial electrochemical technologies and their specific operational mechanism along with their futuristic integrations and developmental models, and draw a conclusion that METs have significant potential to negate the impending energy, and renewable feedstock crisis.
Abstract: Microbial electrochemical technologies (MET) have significant potential to negate the impending energy, and renewable feedstock crisis. METs have evolved into a sustainable and eco-friendly solutions owing to their diverse applications like microbial fuel cell (MFC), for power generation, bioelectrochemical treatment (BET) for wastewater remeduiation, microbial desalination cell (MDC) for salt removal and resource recovery, microbial electrolysis cell (MEC) for the production of Hydrogen by applying external potential and bioelectrochemical syntheis (BES) for value-added products production and other applications such as plant microbial fuel cells (P-MFC) and artificially constructed wetlands fuel cells (CW-MFC) utilize the root exudates for power generation, biosensor applications, etc. This chapter draws light upon the multifaceted application of MET and their specific operational mechanism along with their futuristic integrations and developmental models.
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01 Jan 2019TL;DR: This chapter will provide a bird's eye view on microbial energy generation pathways of versatile microorganisms to exploit them for future bioenergy requirements.
Abstract: Bacteria sustainably evolved through centuries in their diversified metabolism, yet in a close circuit to convert wide spectrum of carbonaceous substances to various energy forms depending on niche environment and biochemical network. The role of biochemical reaction associated with metabolism is to provide either structural or functional components or energy generation for its survival. The energy production is always associated with oxidation–reduction process where an electron donor is oxidized with simultaneous reduction of an electron acceptor along with a shift in free energy among components of reactants. Understanding the physicochemical process conditions along with higher energy–linked metabolic reactions would aid in development of devices or processes such as acidogenesis, methanogenesis, solventogenesis, biopolymers, etc. In this category, advancement has been made in utilization of bacterial molecular machinery to transfer electrons from microbial outer membrane to conductive electrode surfaces. This can be deployed in the development of bioelectrochemical devices such as microbial fuel cells and microbial electrolysis cells for generation of biofuels, bioelectricity, etc. using organic biomass in either solid or liquid form and with exoelectrogenic or electrogenic characteristics of microbes. As these processes are in infancy stage, larger scope is ahead for exploration and exploitation of its relative concerns as well as biochemical pathways toward improving the yields. A deeper understanding of pivotal microbial pathways concerning electroactive biofilm formation, microbe–metal surface interaction, electron transfer machinery, and environment to synthesis of specific redox proteins which involve in transfer of electrons is the most essential requirement for concept to commercialization. This chapter will provide a bird's eye view on microbial energy generation pathways of versatile microorganisms to exploit them for future bioenergy requirements.
4 citations
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01 Jan 2019
TL;DR: A critical review of microbial energy distribution and their disparity as electron losses is presented, which is crucial for identifying suitable application niches and for further advancement in BET exploitation.
Abstract: Microorganisms have a natural intuition to sustain its existence, which involves the exchange of electrons. Linking up the microbial metabolism to electrodes via extracellular electron transfer is now being much explored in bioelectrochemical treatment (BET) involving wastewater. Yet, it is mandatory to look at the sustainable energy yields prior to valorization at commercial plant scale. A proper understanding of stoichiometric energy transitions during treatment of wastewater is crucial for identifying suitable application niches and for further advancement. The most significant barrier to BET exploitation lies in that the process is inherently sensitive to losses, which become dominant during scale-up. A grave issue is the spatial arrangement of electrodes and various other losses viz., ohmic, activation, and mass transfer. This chapter presents a critical review of microbial energy distribution and their disparity as electron losses.
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TL;DR: In this article, the authors employed a model unicellular motile microalga, Chlamydomonas microsphaera, to investigate the microalgal attachment processes onto the electrode surface of a BES and to identify the determinant factors.
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TL;DR: In this article , the authors employed a model unicellular motile microalga, Chlamydomonas microsphaera, to investigate the microalgal attachment processes onto the electrode surface of a BES and to identify the determinant factors.
References
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TL;DR: Interaction of VeA with at least four methyltransferase proteins indicates a molecular hub function for VeA that questions: Is there a VeA supercomplex or is VeA part of a highly dynamic cellular control network with many different partners?
Abstract: Fungal secondary metabolism has become an important research topic with great biomedical and biotechnological value. In the postgenomic era, understanding the diversity and the molecular control of secondary metabolites are two challenging tasks addressed by the research community. Discovery of the LaeA methyltransferase 10 years ago opened up a new horizon on the control of secondary metabolite research when it was found that expression of many secondary metabolite gene clusters is controlled by LaeA. While the molecular function of LaeA remains an enigma, discovery of the velvet family proteins as interaction partners further extended the role of the LaeA beyond secondary metabolism. The heterotrimeric VelB-VeA-LaeA complex plays important roles in development, sporulation, secondary metabolism and pathogenicity. Recently, three other methyltransferases have been found to associate with the velvet complex, the LaeA-like methyltransferase F (LlmF) and the methyltransferase heterodimers VipC-VapB. Interaction of VeA with at least four methyltransferase proteins indicates a molecular hub function for VeA that questions: Is there a VeA supercomplex or is VeA part of a highly dynamic cellular control network with many different partners?
2,234 citations
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TL;DR: It is shown that propane metabolism generated terminal and sub-terminal oxidation products such as 1- and 2-propanol, whereas 1-butanol was the only terminal oxidation product detected from n-butane metabolism.
Abstract: Rhodococcus sp. strain BCP1 was initially isolated for its ability to grow on gaseous n-alkanes, which act as inducers for the co-metabolic degradation of low-chlorinated compounds. Here, both molecular and metabolic features of BCP1 cells grown on gaseous and short-chain n-alkanes (up to n-heptane) were examined in detail. We show that propane metabolism generated terminal and sub-terminal oxidation products such as 1- and 2-propanol, whereas 1-butanol was the only terminal oxidation product detected from butane metabolism. Two gene clusters, prmABCD and smoABCD – coding for soluble di-iron monooxgenases (SDIMOs) involved in gaseous n-alkanes oxidation – were detected in the BCP1 genome. By means of reverse transcriptase-quantitative PCR (RT-qPCR) analysis, a set of substrates inducing the expression of the sdimo genes in BCP1 were assessed as well as their transcriptional repression in the presence of sugars, organic acids or during the cell growth on rich medium (Luria Bertani broth). The transcriptional start sites of both the sdimo gene clusters were identified by means of primer extension experiments. Finally, proteomic studies revealed changes in the protein pattern induced by growth on gaseous- (n-butane) and/or liquid (n-hexane) short-chain n-alkanes as compared to growth on succinate. Among the differently expressed protein spots, two chaperonins and an isocytrate lyase were identified along with oxidoreductases involved in oxidation reactions downstream of the initial monooxygenase reaction step.
1,774 citations
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TL;DR: This Review addresses the principles, challenges and opportunities of microbial electrosynthesis, an exciting new discipline at the nexus of microbiology and electrochemistry.
Abstract: Microbial electrocatalysis relies on microorganisms as catalysts for reactions occurring at electrodes. Microbial fuel cells and microbial electrolysis cells are well known in this context; both use microorganisms to oxidize organic or inorganic matter at an anode to generate electrical power or H(2), respectively. The discovery that electrical current can also drive microbial metabolism has recently lead to a plethora of other applications in bioremediation and in the production of fuels and chemicals. Notably, the microbial production of chemicals, called microbial electrosynthesis, provides a highly attractive, novel route for the generation of valuable products from electricity or even wastewater. This Review addresses the principles, challenges and opportunities of microbial electrosynthesis, an exciting new discipline at the nexus of microbiology and electrochemistry.
1,285 citations
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TL;DR: The molecular mechanisms that underlie the ability of microorganisms to exchange electrons, such as c-type cytochromes and microbial nanowires, with extracellular minerals and with microorganisms of the same or different species are discussed.
Abstract: Electrons can be transferred from microorganisms to multivalent metal ions that are associated with minerals and vice versa. As the microbial cell envelope is neither physically permeable to minerals nor electrically conductive, microorganisms have evolved strategies to exchange electrons with extracellular minerals. In this Review, we discuss the molecular mechanisms that underlie the ability of microorganisms to exchange electrons, such as c-type cytochromes and microbial nanowires, with extracellular minerals and with microorganisms of the same or different species. Microorganisms that have extracellular electron transfer capability can be used for biotechnological applications, including bioremediation, biomining and the production of biofuels and nanomaterials.
1,047 citations
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TL;DR: A mediator-less microbial fuel cell was optimized in terms of various operating conditions and showed linear relationship with the fuel added at low concentration, and the electronic charge was well correlated with substrate concentration from up to 400 mg l(-1) of COD(cr).
963 citations