Laccase Immobilization Strategies for Application as a Cathode Catalyst in Microbial Fuel Cells for Azo Dye Decolourization

Enzymatic biocathodes have the potential to replace platinum as an expensive catalyst for the oxygen reduction reaction in microbial fuel cells (MFCs). However, enzymes are fragile and prone to loss of activity with time. This could be circumvented by using suitable immobilization techniques to maintain the activity and increase longevity of the enzyme. In the present study, laccase from Trametes versicolor was immobilized using three different approaches, i.e., crosslinking with electropolymerized polyaniline (PANI), entrapment in copper alginate beads (Cu-Alg), and encapsulation in Nafion micelles (Nafion), in the absence of redox mediators. These laccase systems were employed in cathode chambers of MFCs for decolourization of Acid orange 7 (AO7) dye. The biocatalyst in the anode chamber was Shewanella oneidensis MR-1 in each case. The enzyme in the immobilized states was compared with freely suspended enzyme with respect to dye decolourization at the cathode, enzyme activity retention, power production, and reusability. PANI laccase showed the highest stability and activity, producing a power density of 38 ± 1.7 mW m−2 compared to 25.6 ± 2.1 mW m−2 for Nafion laccase, 14.7 ± 1.04 mW m−2 for Cu-Alg laccase, and 28 ± 0.98 mW m−2 for the freely suspended enzyme. There was 81% enzyme activity retained after 1 cycle (5 days) for PANI laccase compared to 69% for Nafion and 61.5% activity for Cu-alginate laccase and 23.8% activity retention for the freely suspended laccase compared to initial activity. The dye decolourization was highest for freely suspended enzyme with over 85% decolourization whereas for PANI it was 75.6%, Nafion 73%, and 81% Cu-alginate systems, respectively. All the immobilized laccase systems were reusable for two more cycles. The current study explores the potential of laccase immobilized biocathode for dye decolourization in a microbial fuel cell

Decolourisation of Acid orange 7 in a microbial fuel cell with a laccase-based biocathode: Influence of mitigating pH changes in the cathode chamber

Biocathodes may be a suitable replacement of platinum in microbial fuel cells (MFCs) if the cost of MFCs is to be reduced. However, the use of enzymes as bio-cathodes is fraught with loss of activity as time progresses. A possible cause of this loss in activity might be pH increase in the cathode as pH gradients in MFCs are well known. This pH increase is however, accompanied by simultaneous increase in salinity; therefore salinity may be a confounding variable. This study investigated various ways of mitigating pH changes in the cathode of MFCs and their effect on laccase activity and decolourisation of a model azo dye Acid orange 7 in the anode chamber. Experiments were run with catholyte pH automatically controlled via feedback control or by using acetate buffers (pH 4.5) of various strength (100 mM and 200 mM), with CMI7000 as the cation exchange membrane. A comparison was also made between use of CMI7000 and Nafion 117 as the transport properties of cations for both membranes (hence their potential effects on pH changes in the cathode) are different

ICT SKILLS AMONG TECHNICAL INSTITUTE LIBRARY PROFESSIONALS AT TIRUNELVELI DISTRICT, TAMIL NADU: A STUDY

Information and Communication Technology [ICT] applications have transformed present libraries into digital libraries, electronic libraries and virtual libraries. As such, it has become essential for the college librarians to get expertise in ICT skills. In this regard, training is needed for these library professionals in ICT techniques. Today the world is full of computer based technology segments and the resources are available more and more in the throughout the world. But the humans do not know about the resources and how to co-ordinate it and the professionals do not have adequate ICT skills. The paper talks about the Information and Communication Technology skills of the library professionals. The purpose of the study was examining the various skills of Technical Institute Library Professionals at Tirunelveli District of Tamil Nadu

Boletín Oficial de la Provincia de Guadalajara: Número 19 - 1939 febrero 20

Today E-resources moved toward becoming embodiment of each scholarly action of advanced education. The present study examined the usage of e-resources among the students of Manonmaniam Sundaranar University (MSU), Tirunelveli, Tamil Nadu. A descriptive survey method was adopted by using questionnaire as a tool to collect relevant data from the students. The total population of 135 questionnaires was randomly distributed to the respondents out of which 120 questionnaires was return as filled. The overall response rate was 89%. The main objectives of the study are to determine the awareness, frequency, purpose, access point, factor influence, key constraints and satisfaction of present collection of e-resources in the library. The result of the study reveals that 78.3% of the respondents are aware and used e-resources followed by 63% are using e-resources in the frequency of 2-3 times in a week, 53% are using e-resources for research purpose, 59% are access e-resources in the library, 17.3% are using e-resources to improve professional competence, 39% of the respondents felt that lack of training as a key constraint for the effective use of e-resources and 35% of the respondents are highly satisfied with the present e-collection of the library. This study concludes that Library plays important role in the usage of e-resources by its users. Library needs to facilitate e-resources and to give training for the effective usage of e-resources by the users

Performance Analysis of Autonomous Microgrid Subsequent to Symmetrical and Unsymmetrical Fault Triggered Condition

Hi-tech scenario and the ecological compression are the key point to drive the intervention of the renewable in the distribution system. In the perspective of complex power system planners, the transient performance of the microgrid is the main concern. For that purpose, various fault cases are explored in order to examine the microgrid transient performance when subjected to accidental events. In this work, the microgrid is modelled with two distributed generations (DGs) tied with a converter separately. With this intention, droop control strategy is adopted for the microsources to examine the microgrid performance during the symmetrical and unsymmetrical fault events. The ability of the control strategy adopted in this work and its effectiveness are evaluated through Matlab/Simulink platform