Membraneless enzymatic biofuel cell powered by starch biomass

This present work reports on an eco-friendly and membraneless enzymatic biofuel cell (EBFC) with direct utilization of starch as biofuel. This study examines the compatibility of Metroxylon Sagu (Sago) starch to be used as a substrate in the production of biofuel in EBFC via enzymatic hydrolysis, which has not yet been explored. The hydrolysis is adapted from the idea of simultaneous saccharification and fermentation (SSF), which is widely used in another biofuel production. Alpha-amylase (ĮAmy) and glucoamylase (Gamy) enzymes (1:1 ratio) are used simultaneously in the hydrolysis process of Sago to produce glucose. Membraneless EBFC makes the biofuel cell less bulky and reduces the cost. The presence of glucose after the hydrolysis process was identified using the DNSA method. Meanwhile, the catalytic currents have been successfully observed in the cyclic voltammetry analysis to confirm the redox reaction. Furthermore, the electrochemical performances of the membraneless EBFC were evaluated in terms of the open circuit voltage (OCV) and the maximum power density. All the measurements were carried out with a potentiostat. The best catalytic currents of an EBFC employing 1.5% (w/v) concentration of Sago substrate and 200 l of enzymes and present a maximum power density of 39.3 W cm-2 and an OCV of 0.32 V. The results proved that the direct use of Sago in EBFC successfully produces biofuel and thus generates electricity. Membraneless EBFC is a potential candidate for low-powered implantable and wearable devices

Green synthesis of silver nanoparticles using Sago (Metroxylon Sagu) via auto claving method

Sago (metroxylon sagu) is a polysaccharide bio resource, which is biodegradable and low in toxicity that can be found in large scale in Mukah, Sarawak. A simple green method of synthesizing silver nanoparticles (AgNPs) has been developed using sago dissolved in water as the reducing agent. The mixture of dissolved sago and silver nitrate (AgNO3) were autoclaved at 121 °C for 20 minutes. The size, morphology and structures of the AgNPs formed in the sago solution were investigated through UVVis spectrophotemeter, XRD and FESEM analysis. The synthesized AgNPs were spherical in shape and well distributed with average particle sizes of 19.3 ± 2.7 n

Direct energy conversion from metroxylon sagu via multienzyme catalysis in enzymatic biofuel cell

Biomass substrates have been used extensively in the production of biofuel by the simultaneous saccharification and fermentation (SSF) method. Biomass sources from the plant are preferable to produce biofuel because of the high sugar content. Adapting the SSF method, this work reported on the direct energy conversion from Metroxylon sagu via multienzyme catalysis in an enzymatic biofuel cell (EBFC). Metroxylon sagu locally called Sago is an industrial crop mainly found in Mukah, Sarawak. Sago is a type of starch that consists mainly of amylose and amylopectin structures. In this study, the polysaccharides are converted to glucose using alpha-amylase (α-amylase) and glucoamylase (GAmy) enzymes. The factors influencing the multienzyme catalysis, such as the substrate concentration, enzymes loading, pH and time, were varied to obtain the optimized condition for glucose production. The results of the glucose content using a microplate reader indicate that glucose was successfully produced via multienzyme catalysis. The oxidation of glucose employed in the EBFC was confirmed by the cyclic voltammogram (CV) analysis. The performance of EBFC was also assessed based on its maximum power density (MPD) and open circuit voltage (OCV) values. This multienzyme catalysis simplifies the multi-step process involved in converting polysaccharides to glucose

Antifungal activity of biosynthesized silver nanoparticles mediated by neem leaf extract against aspergillus sp.

Silver nanoparticles (AgNPs) have attracted considerable attraction as excellent antifungal agents against various pathogens. In the present study, AgNPs were biosynthesized using neem leaf aqueous extract, and their antifungal properties were evaluated against Aspergillus sp. The formation of newly synthesized AgNPs was confirmed through visual observation by a change in the color of the solution, followed by an analysis of their surface plasmon resonance via UV-vis spectrophotometer. Further characterization of its crystalline nature and morphology structure was assessed by X-Ray Diffraction (XRD) and Field-emission Scanning Electron Microscope (FESEM), respectively. The result revealed that the synthesized AgNPs showed UV-vis spectra peak around 421 nm, are crystalline in nature, and have a spherical morphology with an average size of 20.13 ± 3.3 nm in diameter. Furthermore, these AgNPs exhibit excellent antifungal activity against the waterborne pathogen Aspergillus sp. on agar well diffusion assay with a maximum 26.54 ± 1.23 mm zone of inhibition. FESEM image revealed hyphal damage and deformation of fungus when treated with AgNPs, causing retardation of fungus growth for further reproduction. The results suggested that this biosynthesis AgNPs from neem leaf extract has great potential as an alternative antifungal agent for use in water treatment

The potential of Moringa oleifera seeds for fungal disinfection in water

Water contamination by fungi has earned more attention by numerous researchers, while disinfection is one of the primary methods used in drinking water treatment process to remove bacteria or fungi. In this work, a pilot study on the characterization and the performance of the regrowth fungal spores on Moringa oleifera (MO) disinfection process were investigated. Firstly, an active compound in MO seeds was extracted and characterized via Fourier-transform infrared (FTIR) and scanning electron microscopy (SEM) analyses. The extract MO then underwent a comparison set of disinfection studies without any disinfectant at different time to evaluate its performance in reducing the growth of fungal spores in water. The disinfection study reveals that fungi's spore’s growth decreased from 71% to 60% from day two until day seven. In addition, these findings indicate that extract MO seeds may be a potential disinfectant for the growth of fungi in drinking water

Development of Solar Biomass Drying System

The purpose of this paper focuses on the experimental pre-treatment of biomass in agricultural site using solar energy as power source and contribution of common use and efficiency solar dryer system for consumer. The main purpose of this design for solar cabinet dryer is to dry biomass via direct and indirect heating. Direct heating is the simplest method to dry biomass by exposing the biomass under direct sunlight. The solar cabinet dryer traps solar heat to increase the temperature of the drying chamber. The biomass absorbs the heat and transforms the moisture content within the biomass into water vapour and then leaves the chamber via the exhaust air outlet. This problem however can be solved by adopting indirect solar drying system. High and controllable temperatures can be achieved as a fan is used to move the air through the solar collector. This project has successfully created a solar cabinet dryer that combines both direct and indirect solar drying systems and functions to dry biomass as well as crops effectively and efficiently with minimal maintenance. Hence, it is indeed a substitution for conventional dryers which are affordable to local farmers

Modeling and Parametric Study for Maximizing Heating Value of Gasification Syngas

There are a number of experimental and theoretical studies on the energy conversion of oil palm derivative biomass. Moreover, the potential of this abundant biomass residue for renewable energy in major producing countries in Southeast Asia has been well documented. In this study, the results of an equilibrium model of downdraft gasification of oil palm fronds (OPF), developed using the Aspen Plus chemical process simulator software, and its validation are presented. In addition, an optimization of the major output parameter of importance (i.e., the higher heating value of syngas) with respect to the main operating parameters (i.e., temperature, equivalence ratio (ER), and moisture content) was performed. The response surface method (RSM) was used to determine the mathematical relationship between the response of interest, which was the heating value of syngas, and the operating conditions. This method was used to further determine the conditions that would lead to optimum higher heating values of syngas. Optimum values identified by RSM were: oxidation zone temperature of 1000 °C, moisture content in the range of 4%, and an equivalence ratio of 0.35. These optimum operating conditions and the corresponding higher heating value of syngas were found to correspond with the experimental results

Microbial lipid accumulation through bioremediation of palm oil mill effluent using a yeast-bacteria co-culture

Co-cultures of different microorganisms are considered promising inocula for treating palm oil mill effluents (POME) and producing value-added bio-products (e.g., biofuels and fatty acid-derived materials). However, the efficiency of yeast-bacteria co-culture for microbial lipid production through bioremediation of wastewater remains a bottleneck. In this study, the performance of a co-culture for lipid accumulation through POME bioremediation was investigated using a yeast (Lipomyces starkeyi) and a bacterium (Bacillus cereus). A maximum biomass of 8.89 ± 0.33 g/L and lipid production of 2.27 ± 0.10 g/L were achieved by the co-culture inoculum, which were substantially higher than those of the monocultures. Besides, the co-culture inoculum attained a maximum chemical oxygen demand (COD) removal of 83.66 ± 1.9%, while the individual cultures of B. cereus and L. starkeyi obtained 74.35 ± 1.7% and 69.01 ± 2.3%, respectively. The bioremediation efficiency was confirmed by the seed germination index (GI) of Vigna radiata (Mung bean). It was observed that the co-culture inoculum had a higher GI compared to the untreated POME and even the monoculture-treated POME. We argue that the symbiotic association of a yeast-bacteria co-culture in POME could be an attractive approach for achieving maximum biomass as well as lipid production and simultaneous bioremediation of POM

Effect of Welding Speed on Microstructure and Mechanical Properties due to The Deposition of Reinforcements on Friction Stir Welded Dissimilar Aluminium Alloys

The strength of the welded joint obtained by solid state stir welding process was found to be improved as compared to fusion welding process. The deposition of reinforcements during friction stir welding process can further enhance the strength of the welded joint by locking the movement of grain boundaries. In the present study, the aluminium alloys AA2024 and AA7075 were welded effectively by depositing the multi-walled carbon nanotubes in to the stir zone. The mechanical properties and microstructures were studied by varying the traverse speed at constant rotational speed. The results show that rotating tool pin stirring action and heat input play an important role in controlling the grain size. The carbon nanotubes were found to be distributed uniformly at a welding speed (traverse speed) of 80mm/min. This enhanced the mechanical properties of the welded joint. The microstructure and Electron dispersive X-ray analysis (EDX) studies indicate that the deposition of carbon nanotubes in the stir zone was influenced by the traverse speed

Effect of Welding Speed on Microstructure and Mechanical Properties due to The Deposition of Reinforcements on Friction Stir Welded Dissimilar Aluminium Alloys

The strength of the welded joint obtained by solid state stir welding process was found to be improved as compared to fusion welding process. The deposition of reinforcements during friction stir welding process can further enhance the strength of the welded joint by locking the movement of grain boundaries. In the present study, the aluminium alloys AA2024 and AA7075 were welded effectively by depositing the multi-walled carbon nanotubes in to the stir zone. The mechanical properties and microstructures were studied by varying the traverse speed at constant rotational speed. The results show that rotating tool pin stirring action and heat input play an important role in controlling the grain size. The carbon nanotubes were found to be distributed uniformly at a welding speed (traverse speed) of 80mm/min. This enhanced the mechanical properties of the welded joint. The microstructure and Electron dispersive X-ray analysis (EDX) studies indicate that the deposition of carbon nanotubes in the stir zone was influenced by the traverse speed