Dry Cell Research Articles

Selective Oxidation of Biomass derived 5-Hydroxymethylfurfural (HMF) to 2,5-Diformylfuran (DFF) over Spent Dry cell battery cathode material (BCM-2)

Selective Oxidation of Biomass derived 5-Hydroxymethylfurfural (HMF) to 2,5-Diformylfuran (DFF) over Spent Dry cell battery cathode material (BCM-2)

Low-Cost Laser Security System with Intrusion Detection and Alert Mechanism

Security becomes necessary factor nowadays. The crime gang improves their technology to perform their operation along with the development of technology. Hence, technology of security should be more improved to protect the crime works. We have decided to make a security project. In this project we have used laser light for security purpose. We know laser light goes through long distance. When any person or object passes through the laser line, the security alarm will start to ring. There are two parts of the system. One is transmitter and other is receiver. The transmitter side consists of a pair of dry cell batteries and an on-off switch. The receiver side, there is a focusing LDR (Light Dependent Resistor) sensor to sense the laser ray. It is connected with the main driver circuit which has two parts. One is signal of discontinuity ray and other is alarm circuit. When anybody passes through the ray, the main circuit sense the discontinuity and turn on the alarm circuit. The alarm will be ringing until the off button is pressed. There are two methods of ringing. One is the duration of ringing depends on preset timer and another is reset manually. Any option can be set by DPDT switch. We have used second method for our project. Mirrors are attached at every corner to reflect the ray coming from the laser. The reflected ray coming from the last mirror will hit the LDR directly. The system has built with low cost and high performance. The power consumption of the system is very low.

Extending the G1 phase improves the production of lipophilic compounds in yeast by boosting enzyme expression and increasing cell size

Cell phase engineering can significantly impact protein synthesis and cell size, potentially enhancing the production of lipophilic products. This study investigated the impact of G1 phase extension on resource allocation, metabolic functions, and the unfolded protein response (UPR) in yeast, along with the potential for enhancing the production of lipophilic compounds. In brief, the regulation of the G1 phase was achieved by deleting CLN3 (G1 cyclin) in various yeast strains. This modification resulted in a 83% increase in cell volume, a 76.9% increase in dry cell weight, a 82% increase in total protein content, a 41% increase in carotenoid production, and a 159% increase in fatty alcohol production. Transcriptomic analysis revealed significant upregulation of multiple metabolic pathways involved in acetyl-CoA (acetyl coenzyme A) synthesis, ensuring an ample supply of precursors for the synthesis of lipophilic products. Furthermore, we observed improved protein synthesis, attributed to UPR activation during the prolonged G1 phase. These findings not only enhanced our understanding and application of yeast's capacity to synthesize lipophilic compounds in applied biotechnology but also offered unique insights into cellular behavior during the modified G1 phase, particularly regarding the UPR response, for basic research. This study demonstrates the potential of G1 phase intervention to increase the yield of hydrophobic compounds in yeast, providing a promising direction for further research.

Repeated Fed-Batch Culture Strategy for the Synthesis of Polyhydroxybutyrate (PHB) Biopolymers from Sugar Cane Juice Using Azotobacter vinelandii

In this research work, a main biopolymer group of polyhydroxyalkanoates (PHAs) in the form of polyhydroxybutyrate (PHB) was synthesised by a pure bacterial strain of Azotobacter vinelandii via repeated fed-batch fermentation. An agricultural crop, sugar cane, was used as the sole carbon source. Firstly, batch fermentation was investigated considering variations in incubation times (24 h, 48 h, and 96 h). The highest dry cell weight (DCW) and PHAs of 5.15 ± 0.04 g/L and 4.00 ± 0.04 g/L were obtained after 48 h of incubation time. The optimum time obtained was further varied to investigate the effect of the sugar concentrations in the medium. It was found that bacteria could grow very well and produced the highest DCW and PHAs (11.17 ± 0.15 g/L and 8.77 ± 0.06 g/L) when the culture medium with a 100 g/L sugar concentration was added. Later, repeated fed-batch fermentation was carried out to improve productivity. The results obtained revealed that PHA production was increased in the next cycle of the process. Furthermore, the final productivity (0.104 g/L·h) was increased 1.65-fold compared to the first cycle (0.063 g/L·h). Moreover, the culture strategy showed remarkable results, with reductions in both fermentation time and preparation cost.

De Novo Production of the Bioactive Phenylpropanoid Artepillin C Using Membrane-Bound Prenyltransferase in Komagataella phaffii.

Artepillin C is a diprenylated phenylpropanoid with various pharmacological benefits for human health. Its natural occurrence is limited to a few Asteraceae plants, such as Baccharis species, necessitating a stable supply through synthetic biology. In Saccharomyces cerevisiae, the utilization of aromatic substrates within the cell was limited, resulting in very low production of artepillin C. In this study, we used AcPT1, a p-coumaric acid (p-CA)-specific diprenyltransferase, in Komagataella phaffii to produce artepillin C. Detailed studies revealed that the critical bottleneck in K. phaffii was the supply of prenyl diphosphates, not phenylpropanoid flux. By enhancing the prenyl substrate pathway through overexpression of isopentenyl diphosphate isomerase and a truncated HMG-CoA reductase, we achieved a strong increase in artepillin C production. A major part of artepillin C was accumulated in yeast cells. One of the advantages of K. phaffii is its superior growth and ability to achieve high cell density cultivation compared to that of S. cerevisiae. Therefore, fed-batch cultivation with glycerol was performed. As a result, the dry cell weight (DCW) reached 61.0 g/L, and the intracellular amount of de novo produced artepillin C reached 187.3 μg/DCW. Analysis of intermediates revealed that the supply of p-CA constituted a bottleneck in artepillin C production in the engineered strain. By enhancing the p-CA supply, the intracellular accumulation of artepillin C reached 1200 μg/DCW even in batch cultivation. Moreover, the total intra- and extracellular amounts of artepillin C reached 12.5 mg/L, marking the highest de novo synthesis amount of artepillin C reported thus far, even under batch cultivation conditions.

Triple-Gene Overexpression of the AcrA-AcrB-TolC Transporter System in Synechocystis sp. PCC 6803 Contributes to a Higher Secretion of Free Fatty Acids in Response to Nitrogen Shortage and Salt Stress

One important aspect of cyanobacterial homoeostasis is reducing the toxicity of excess free fatty acids (FFAs) generated in the cells by means of both secreting these into the medium and recycling them toward membrane lipid synthesis. In this study, the cyanobacterium Synechocystis sp. PCC 6803 served to implement the overexpression of native genes of the transportation system. Specifically, we worked with the Sll0180-Slr2131-Slr1270 homologs of Escherichia coli AcrA-AcrB-TolC, respectively, to create single- and triple-overexpressing strains of OA, OB, OC, and OABC. Remarkably, the OABC strain that triply overexpressed the sll0180_slr2131_slr1270 genes acquired a significant amount of intracellular lipids, up to 23.5% of dry cell weight, under the normal condition. Nitrogen-deficient stress undoubtedly raised extracellular FFAs and intracellular lipids in overexpressing strains, especially in the OABC strain, which exhibited 33.9% and 41.5% of dry cell weight, respectively. During the first 5 days of treatment, salt stress at 256 mM significantly increased the FFA efflux, notably for the OB strain, but had no effect on intracellular lipids. It is noteworthy that the OA and OABC strains outperformed all other strains in terms of growth throughout the 16 days of nitrogen shortage. Furthermore, in comparison to the wild-type control, all the overexpressing strains exhibited a considerable increase in carotenoid accumulation. Thus, our results point to the effective role of the sll0180_slr2131_slr1270 transportation system in facilitating FFA secretion, especially in response to environmental stressors.

From coffee waste to nutritional gold: bioreactor cultivation of single‐cell protein from Candida sorboxylosa

AbstractBACKGROUNDIndustrial effluents are continuously discharged into the environment. These wastewaters contain valuable compounds that can be reused for biotechnological applications. Coffee wastewater (CWW) is a powerful effluent that can be used for single‐cell protein (SCP) production reaching important content (up to 80%). Several yeast species can be used for SCP production, but Candida species are commonly applied for this purpose (17 species reported including the novel C. sorboxylosa). In addition, SCP can be produced in bioreactors under controlled conditions under three operation modes. Thus, batch mode is frequently used but continuous mode presents interesting advantages in economic terms, although it has been poorly applied in SCP production.RESULTSThe initial evaluation under batch operation mode showed that volumetric oxygen transfer coefficient (kLa of 101 h−1) improved biomass production (1.39 g L−1) and SCP yield (59.9%) in C. sorboxylosa. Thus, continuous mode was established at selected kLa and feeding with optimized medium composed of 87.5% (v/v) CWW, 1.38 g L−1 yeast extract, and 7.24 g L−1 (NH4)2SO4, in order to provided necessary nutrients. In this sense, the process presented higher values in dry cell weight and SCP productivity (0.57 and 0.29 g L−1·h, respectively), achieving a 3.35‐ and 2.90‐fold increase in biomass and protein productivity, respectively, compared to batch mode. The SCP from C. sorboxylosa exhibited an interesting essential amino acid profile under continuous mode (33.704%).CONCLUSIONThe bioprocess highlights several advantages during bioreactor cultivation, including: (i) reduced energy consumption for temperature control; (ii) successful establishment of an initial continuous operation mode with promising performance; and (iii) SCP from C. sorboxylosa exhibited a notable composition of essential amino acids, which could be beneficial for potential use in animal feed. © 2024 Society of Chemical Industry (SCI).

Factors influencing management of dry cell battery waste: a case of Greater Accra Region in Ghana

Indiscriminate disposal of dry cell battery (DCB) waste contributes to environmental and public health issues in developing countries such as Ghana, due to the toxic nature of this specific waste. Accordingly, a study was conducted in Accra, Ghana, to determine the socio-economic and demographic factors influencing handling DCB waste, aiming a sustainable environment. Using a random sampling technique, a descriptive cross-sectional survey was conducted, encompassing 367 respondents from the Accra-Tema Metropolitan areas and Tema West Municipal Assembly in Greater Accra, Ghana. Using descriptive and multivariate statistical methods, the survey data were analysed with the Statistical Package for Social Sciences (SPSS) version 27. The results of this study show that female gender and residential area are likely to positively influence the use of DCB at home. Education significantly affects the use of DCB and its proper disposal. The results also suggest that 78% of the respondents disposed of DCB waste in waste bins. The mean monthly income of the respondents stands at USD 270, which is average and likely partially to positively influence the disposal of the DCB. The data collected revealed that female gender, age group, family size, and education level influence the indiscriminate disposal of DCB waste and DCB waste recycling. The results highlight that educated females above the age of 55, with a monthly income, are likely to properly segregate DCB waste. This study contributes to the knowledge gap in relation to dry cell battery waste management (DCBWM) in developing countries, aiming to advance global sustainability. This study is expected to contribute to educate and create awareness in managing DCB waste to reduce its indiscriminate disposal which leads to environmental pollution and negatively affects human health and environmental sustainability in Ghana.

A high-performance ray tracing particle tracking model for the simulation of microplastics in inland and coastal aquatic environments

In this study, we present a high-performance Particle Tracking Model (PTM) designed for simulating any type of particles, with a focus on microplastics. The PTM is efficient compared to existing models, parallelized, and utilizes a ray tracing algorithm incorporating both ray reflection and ray refraction in order to traverse particles as well as find the location of each particle over three-dimensional unstructured grids. Various numerical corrections are implemented in the model to address computational round-off errors and discontinuities in the water surface level of the input hydrodynamic models. To increase the accuracy of the model, partially reflective boundary conditions are imposed as well as the capability to simulate microplastics beaching and washout in very shallow areas or dry computational cells. Several tests are conducted to study the performance, scalability, and accuracy of the model. The proposed model is tested with over 3.88 billion double-precision particles on three-dimensional computational grids with up to approximately one million cells. The tests show that the ray tracing approach is efficient, achieves over 17× faster runtime, and offers greater accuracy compared to using an auxiliary grid for particle location finding. For larger timesteps, the ray tracing PTM with refraction shows improved accuracy compared to the ray tracing PTM without refraction. The model's capabilities are tested in a real-world case study over the Saguenay Fjord, Quebec, Canada. The model is utilized to reproduce the paths of five surface drifters. A second numerical test is conducted in the Fjord and high particle concentration areas are identified.

Comparative analysis of powertrain architectures for fuel cell light commercial vehicles in terms of performance and durability

At the present time, the critical climate situation has raised awareness about the importance of developing carbon-free technologies. In this context, fuel cell systems (FCS) have become one of the key technologies in the pathway to decarbonization. Given that road transport is a major contributor to greenhouse gas (GHG) emissions, this paper focuses on a specific segment of this sector: light commercial vehicles (LCVs). The current market situation shows that LCV manufacturers have not yet decided what is the appropriate powertrain architecture for this kind of vehicle. Thus, the current paper studies a wide range of possible FCS-based propulsive system designs, changing the size of the FCS, electric battery and H2 tank. These propulsive system architectures are analyzed concerning the performance of the vehicle, in terms of consumption and range, and the durability of its FCS. The evaluation of these different designs will be highly valuable for the LCV industry and manufacturers, as it allows to understand the optimal powertrain solution. The study demonstrates that a significant increase in range can be achieved with only a minor penalty in hydrogen consumption. Additionally, the research indicates that it is feasible to employ one of the most durable FCS designs while meeting LCV mission requirements with minimal consumption penalty. In conclusion, this paper provides valuable data to the ongoing research in this field, offering a detailed analysis of the impact of H2 consumption, autonomy, and durability of the FCS across various vehicle architectures under typical LCV driving conditions.

Mechanisms of Thermal Decomposition in Spent NCM Lithium-Ion Battery Cathode Materials with Carbon Defects and Oxygen Vacancies.

Resource recovery from retired electric vehicle lithium-ion batteries (LIBs) is a key to sustainable supply of technology-critical metals. However, the mainstream pyrometallurgical recycling approach requires high temperature and high energy consumption. Our study proposes a novel mechanochemical processing combined with hydrogen (H2) reduction strategy to accelerate the breakdown of ternary nickel cobalt manganese oxide (NCM) cathode materials at a significantly lower temperature (450 °C). Particle refinement, material amorphization, and internal energy storage are considered critical success factors for the accelerated decomposition of NCM cathode materials. In our proposed approach, NCM cathode materials can develop active sites with carbon defects (Cv) and oxygen vacancies (Ov), which improve the reduction and breakdown of H2. The adsorbed H2 on the surface of NCM decomposes into H* and combines with oxygen to form OH species, which can be facilitated by Ov via the enhanced charge transfer. The introduced Cv can enhance H2 cracking and generate *C-H species to promote the thermal decomposition of NCM. The presence of defects proves to foster the preferential reduction of Mn(IV) by H2, leading to a lower activation energy for the NCM decomposition (from 139 to 110 kJ/mol) with less H2 consumption. Life cycle assessment suggests a reduction of 4.42 kg CO2 eq for the recycling of every 1.0 kg of retired batteries. This study can promote material circularity and minimize the environmental burden of mining technology-critical metals for a low-carbon transition.

Sustainable remediation of piggery wastewater using a novel mixotrophic Chlorella sorokiniana Cbeo for high value biomass production

Piggery wastewater (PW) contains high density of organic carbon (COD), nitrogen (NH4+-N and TN) and phosphorous (TP), which are essential nutrients for microalgae growth. This work was attempted to use a newly isolate Chlorella sorokiniana Cbeo for recovery these compounds into its biomass via mixotrophic cultivation. Critical factors including level of ammonia, C/N ratio, pH, light intensity, sterilized/unsterilized media, and indoor/outdoor cultivations affecting biomass production and nutrients removal efficiencies were investigated. Data revealed that C. sorokiniana Cbeo achieved the optimal growth in the unsterilized medium at NH4+-N concentration, C/N ratio, initial pH, and light intensity of 250mg/L, 10/1, 7, and 150 μmol/m2/s, respectively. Under the optimal conditions, dry cell weight (DCW) reached the maximal level of 4.30g/L, which was slightly higher than 4.14g/L determined for the sterilized medium. In 30 L-scale photobioreactor, C. sorokiniana Cbeo grown under indoor and outdoor achieved DCW of 3.61 and 3.19g/L, respectively. COD, NH4+-N, TN, TP removal efficiencies for both conditions were determined as 91.9–96.7, 96.6–99.7, 96.2–96.4, and 98.2–100%, respectively. The C. sorokiniana Cbeo biomass contained 14–27% lipid, 25–32% carbohydrate, 44–48% protein, and 0.25–0.97% lutein. Interestingly, α-Linolenic acid (C18:3n3) was 19.84 –27.0% of the total fatty acids. C. sorokiniana Cbeo is the promising algal strain for development of a sustainable biorefinery of PW.

Electric Bicycle Battery Charging System Design Using Solar Panel

This solar-powered electric bicycle charging system design and development uses solar panels as a renewable energy source to charge the battery, which drives the electric motor. The system consists of four main components: solar panel, solar charge controller, battery, and electric motor. The solar panels are connected in parallel to generate 36V, which is then stored in the battery. The system is designed to optimize energy harvesting and reduce dependence on fossil fuels. Testing was conducted with research stages, including system design, hardware implementation, and testing. The results show that the system can charge the battery efficiently, with a charging time of 3 hours. The system was also tested under different conditions, including morning, afternoon, and night, to evaluate its performance. It can be concluded that the solar-powered electric bicycle charging system is a viable alternative to traditional fossil fuel-based systems. The system is environmentally friendly, reduces energy dependence, and provides a sustainable solution for transportation. The results of this research can be used to develop a more efficient and sustainable transportation system.

Exploring the Potential of Nyonya Kuih Residues as the Substrate for Yeast Cell Protein Production

Nyonya kuih, a popular Malaysian traditional cuisine that have short shelf life due to their high moisture and fat contents. The unsold kuihs usually ended up as food residue. Thus, kuih talam(KT) and kuih lapis (KL), two varieties of Nyonya kuih were chosen as the investigative substrates to explore the recycling potential of this food residue. Initially, the effect of fat content on the enzymatic hydrolysability of the residues to release fermentable sugar was investigated. The efficiency of lipase-pretreatment (LP), polyvinylpyrrolidone-post-treatment (PVP) and their combination in lipid removal was determined. Then, the potential of the resulting glucose-rich hydrolysates for Saccharomyces cerevisiae yeast cell biomass production was assessed, with molasses as the positive control. Results indicated that combined LP and PVP (LP-PVP) significantly (p<0.05) reduced crude fat content, while increasing the total sugar content of KT and KL hydrolysates by approximately 3.4 and 26.3 times, respectively. Yeast cell biomass produced from KT and KL hydrolysates were increased by 23% and 39%, respectively after LP-PVP treatment. Despite the yeast cells’ yield (by dry cell weight) from molasses fermentation being 19% and 11% higher than those from KT and KL hydrolysates, respectively, KT and KL hydrolysates were proven superior due to the significantly higher (p<0.05) crude protein content in yeast cell produced from both hydrolysates. Further study is needed to enhance yeast cell yield from the fermentation of KT and KL hydrolysates, thereby improving the overall protein yield from the fermentation process. This study provides new insight into a novel food residue recycle strategy, promoting sustainable food production aligned with SDG 12.

Gene editing technology combined with response surface optimization to improve the synthesis ability of lycopene in Pantoea dispersa MSC14.

The aim of this study is to engineer Pantoea dispersa MSC14 into a strain capable of producing lycopene and to enhance its lycopene content. Our laboratory isolated the strain P. dispersa MSC14 from petroleum-contaminated soil in a mining area. Whole-genome sequencing confirmed the existence of a carotenoid synthesis pathway in this strain. This study employed an optimized CRISPR/Cas9 system to perform a traceless gene knockout of the lycopene cyclase gene crtY and to overexpress the octahydrolycopene dehydrogenase gene crtI in the P. dispersa MSC14. This strategic genetic modification successfully constructed the lycopene-producing strain MSC14-LY, which exhibited a notable lycopene content with a biomass productivity of 553μg of lycopene per gram dry cell weight(DCW). Additionally, the components of the lycopene fermentation medium were optimized using Plackett-Burman (PB) design and Response Surface Methodology (RSM). The average lycopene content was increased to 5.13mg g -1DCW in the optimized LY fermentation medium. Through genetic engineering, P. dispersa MSC14 was transformed into a strain capable of producing lycopene, achieving a yield of 5.13mg g-1 DCW after medium optimization. Genetic engineering successfully transformed P. dispersa MSC14 into a strain capable of producing lycopene, achieving a yield of 5.13mg g-1 DCW after medium optimization.

BATERIAS DE CARROS ELÉTRICOS: MANUTENÇÕES E DESCARTES

The rapid growth in the adoption of electric vehicles brings to light challenges related to the maintenance and disposal of batteries, which are essential components for the operation of these vehicles. The central issue addressed is the sustainability of the battery life cycle, considering both the efficiency of their maintenance and the environmental impacts resulting from inadequate disposal. The context involves the transition to a greener economy and the demands for clean technologies, which makes it essential to discuss appropriate practices to extend the useful life of batteries and ensure their safe disposal. The main objective of this study is to analyze the maintenance practices of electric car batteries and disposal strategies, focusing on minimizing environmental impacts and optimizing the life cycle of components. The research seeks to identify effective methods to extend the useful life of batteries, in addition to evaluating existing recycling policies and processes. The methodology used includes a literature review of current battery maintenance and disposal practices, in addition to the analysis of case studies that exemplify different approaches and results in international contexts. The research also incorporates interviews with industry experts, aiming to obtain a comprehensive and updated view of best practices and challenges faced. This work contributes to the discussion on sustainability in the automotive sector and to the formulation of more efficient policies for the management of technological waste.

Decarbonization costs for the Swedish heavy-duty road fleet: Circular economy insights on electric truck batteries

This study analyzes decarbonization costs for the Swedish heavy-duty road fleet under five scenarios, one taken from the EUCalc model as a reference scenario and four others driven by interviews: a high-speed transition with 100% battery electric vehicles (BEVs) across all distances; a high-speed transition with BEVs taking 100% of the market in local and regional distances and 40% in long distances, with the remaining 60% being fuel cell vehicles (FCVs) by 2050; a low-speed transition with BEVs market share increasing by 15% every five years, starting at 10% from 2025 for local and 2030 for regional and long distances; and a low-speed transition similar to the previous scenario, but with 60% of the electrified long-distance fleet to be FCVs. The system's expenses are then calculated through numerical modeling. The study links research on the costs of sustainability transition to a circular economy by analyzing the effect of charging range and temperature on battery degradation for BEVs and their impact on the batteries' valorization. In full electrification scenarios, despite lower operating expenses, the system incurs a higher total cost because of higher investment expenses. Charging–discharging pattern and temperature impact the remaining capacity, and therefore salvage value, of end-of-life batteries.

Decarbonizing Public Transportation: A Multi-Criteria Comparative Analysis of Battery Electric Buses and Fuel Cell Electric Buses

To combat global warming, many industrialized countries have announced plans to ban vehicles powered by fossil fuel in the near future. In alignment with this global initiative, many countries across the globe are committed to decarbonizing their public transportation sector, which significantly contributes to increased greenhouse gas emissions. A promising strategy to achieve this goal is the adoption of electric buses, specifically battery electric buses and fuel cell electric buses. Each technology offers distinct advantages and drawbacks, making the decision-making process complex. This research aims to answer two critical questions: What is the optimal choice for decarbonizing the bus transportation sector—electric battery buses or fuel cell electric buses? And what are the best energy carrier pathways for charging or refueling these buses? We propose a methodological framework based on multi-criteria decision-making to address these questions comprehensively. This framework utilizes the entropy weighting and the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) methodologies to rank alternative bus technologies along with energy carrier pathways. The framework evaluates a range of criteria, including economic viability, energy demand, and environmental aspects. To illustrate the framework, we considered Qatar as a case study. Our results indicate that, with respect to economic viability and energy consumption, the operation of battery electric buses is favored over fuel cell electric buses, regardless of the energy pathway utilized during both the energy production and bus operation phases. However, from an environmental perspective, operating both bus alternatives using energy from green sources provides superior performance compared to when these buses are powered by natural gas sources.

Reengineering the Substrate Tunnel to Enhance the Catalytic Efficiency of Squalene Epoxidase.

Squalene epoxidase plays a pivotal role in the biosynthesis of ergosterol, its derivatives, and other triterpenoid compounds by catalyzing the transformation of squalene into 2,3-oxidosqualene. However, its low catalytic efficiency remains a primary bottleneck for the microbial synthesis of triterpenoids. In this study, the catalytic activity of the squalene epoxidase from Saccharomyces cerevisiae was significantly improved by reshaping its substrate tunnel, resulting in a marked increase in the yield of the final product, ergosterol. First, the amino acid in the catalytic pocket of squalene epoxidase was replaced with alanine (Ala), effectively reducing the steric hindrance, and thus, enhancing the affinity of the enzyme with its substrate. Then, the V249H/L343A mutant was obtained by redesigning the substrate tunnel of dominant mutant L343A, thus, increasing the titer of ergosterol. The study also elucidated the mechanism behind the increased catalytic activity of the V249H/L343A mutant through substrate tunnel parameter analysis and molecular dynamics simulations. Finally, a titer of 3345 mg/L of ergosterol was achieved by strains containing V249H/L343A in a 5 L bioreactor, with a specific yield of 84 mg/g dry cell weight (DCW), marking a 64% increase compared with the titer achieved by wild type strains. This study established a strong foundation for improving the synthetic efficiency of ergosterol and other triterpenoid compounds.

E-waste driven eco-friendly highly sensitive wearable capacitive sensors for physical activity monitoring and sign language recognition

Owing to the continual and rapid advancement in technology, there has been a significant surge in electronic waste (e-waste) in recent decades, resulting in a harmful impact on our environment. Due to the growing demand for battery-powered devices, non-rechargeable batteries are a significant source of e-waste. This study describes fabricating a paper-based graphite strain sensor that is eco-friendly, inexpensive, biodegradable, and sensitive to the applied strain. Readily accessible materials are employed to design and fabricate MIDC strain sensors. The Modified Interdigital Capacitor (MIDC) structure is formed on basic printing paper, and the conductive substance made with the ink of a gel pen and graphite from a drained dry cell is painted on the paper and used as electrode material. The suggested sensor has a high gauge factor value of 1998.578 and fast response and recovery time of 112 ms and 100 ms, respectively. The proposed prototype has also been utilized to inspect fitness exercises and physical activities on the human body, inspiring the potential for its integration into wearable systems for various applications. Reliable detection and differentiation of finger positions are achieved, highlighting the sensor's potential for more advanced sign language applications. It’s a good option to integrate the suggested strain sensor in wearable systems, such as telemedicine systems, electromechanical detection, healthcare, and physical activity monitoring of humans.