Dry Cell Research Articles

Online modeling method for composite load model including EVs and battery storage based on measurement data

Load models have a significant influence on power system simulation. However, current load modeling approaches can hardly satisfy the diversity and time-varying characteristics of loads [including electric vehicles (EVs) and battery storage] in terms of model accuracy and computing efficiency. An online modeling method for composite load models based on measurement information is proposed in this paper. Firstly, the dominant factors in load model output are analyzed based on the active subspace of parameter space. Then the clustering algorithm is applied to cluster the large number of underlying loads based on the characteristics of load daily output curves. Finally, the underlying loads are equivalently aggregated from the low voltage levels to the high voltage levels to construct the composite load model. Simulation results obtained based on PSCAD/EMTDC demonstrate that the load model constructed by the proposed approach can accurately reflect the actual load characteristics of a power system.

The role of storage and flexibility in the energy transition: Substitution effect of resources with application to the Portuguese electricity system

The energy transition, characterized by the decarbonization of energy consumption through electrification, needs a massive integration of non-dispatchable renewable electricity generation, along with storage systems and demand flexibility to manage the variability and uncertainty inherent of these sources. Within this framework, understanding the dynamic interaction among system resources becomes crucial to assess the adequacy of future electricity systems performance. This study aims to evaluate the extent to which new electricity resources will complement or substitute each other in integrating non-dispatchable electricity generation. Using the SWHORD simulator, we investigated the Portuguese power system's for the 2030 horizon, evaluating the coherence of targets outlined in the National Energy and Climate Plan (NECP 2030) while considering interactions among demand-side flexibility and storage options. A significant substitution effect is identified among demand resources, including electric vehicles, hydrogen production, hydro-pumping storage, and battery storage systems. Furthermore, we confirm the consistency of targets set in the Portuguese NECP 2030 and highlight their strong interdependence, particularly concerning renewable and hydrogen targets.

Surface-Displayed Mannanolytic and Chitinolytic Enzymes Using Peptidoglycan Binding LysM Domains.

Using Lactiplantibacillus plantarum as a food-grade carrier to create non-GMO whole-cell biocatalysts is gaining popularity. This work evaluates the immobilization yield of a chitosanase (CsnA, 30 kDa) from Bacillus subtilis and a mannanase (ManB, 40 kDa) from B. licheniformis on the surface of L. plantarum WCFS1 using either a single LysM domain derived from the extracellular transglycosylase Lp_3014 or a double LysM domain derived from the muropeptidase Lp_2162. ManB and CsnA were fused with the LysM domains of Lp_3014 or Lp_2162, produced in Escherichia coli and anchored to the cell surface of L. plantarum. The localization of the recombinant proteins on the bacterial cell surface was successfully confirmed by Western blot and flow cytometry analysis. The highest immobilization yields (44-48%) and activities of mannanase and chitosanase on the displaying cell surface (812 and 508 U/g of dry cell weight, respectively) were obtained when using the double LysM domain of Lp_2162 as an anchor. The presence of manno-oligosaccharides or chito-oligosaccharides in the reaction mixtures containing appropriate substrates and ManB or CsnA-displaying cells was determined by high-performance anion exchange chromatography. This study indicated that non-GMO Lactiplantibacillus chitosanase- and mannanase-displaying cells could be used to produce potentially prebiotic oligosaccharides.

Management of toxic waste released by incorrectly discarded batteries in Brazil

Abstract The main difference between a dry cell battery and an alkaline one is the composition of the electrolyte. In zinc–carbon batteries, dry cell, the electrolyte is a paste formed by mixing ammonium chloride and zinc chloride, whereas in alkaline batteries, the electrolyte is a concentrated aqueous solution of potassium hydroxide containing a certain amount of zinc oxide, hence the name alkaline for this battery. Therefore, the improper disposal of these materials has numerous consequences for the environment, since the potentially toxic metals present in them can be leached, infiltrating, and contaminating the soil layers, the groundwater, as well as the fauna and flora of the regions nearby. Thus, the objective is to perform studies that aim to simulate and analyze the release of potentially toxic metals present in batteries found in normal environmental conditions, through leaching tests from regular batteries (Zn–C) on fertilized soil, simulating a landfill, in addition to tests on sandy soil in order to aid the identification of possible waste release.

New Solutions in Single-Cell Protein Production from Methane: Construction of Glycogen-Deficient Mutants of Methylococcus capsulatus MIR

The biotechnology of converting methane to single-cell protein (SCP) implies using fast-growing thermotolerant aerobic methanotrophic bacteria. Among the latter, members of the genus Methylococcus received significant research attention and are used in operating commercial plants. Methylococcus capsulatus MIR is a recently discovered member of this genus with the potential to be used for the purpose of SCP production. Like other Methylococcus species, this bacterium stores carbon and energy in the form of glycogen, particularly when grown under nitrogen-limiting conditions. The genome of strain MIR encodes two glycogen synthases, GlgA1 and GlgA2, which are only moderately related to each other. To obtain glycogen-free cell biomass of this methanotroph, glycogen synthase mutants, ΔglgA1, ΔglgA2, and ΔglgA1ΔglgA2, were constructed. The mutant lacking both glycogen synthases exhibited a glycogen-deficient phenotype, whereas the intracellular glycogen content was not reduced in strains defective in either GlgA1 or GlgA2, thus suggesting functional redundancy of these enzymes. Inactivation of the glk gene encoding glucokinase also resulted in a sharp decrease in glycogen content and accumulation of free glucose in cells. Wild-type strain MIR and the mutant strain ΔglgA1ΔglgA2 were also grown in a bioreactor operated in batch and continuous modes. Cell biomass of ΔglgA1ΔglgA2 mutant obtained during batch cultivation displayed high protein content (71% of dry cell weight (DCW) compared to 54% DCW in wild-type strain) as well as a strong reduction in glycogen content (10.8 mg/g DCW compared to 187.5 mg/g DCW in wild-type strain). The difference in protein and glycogen contents in biomass of these strains produced during continuous cultivation was less pronounced, yet biomass characteristics relevant to SCP production were slightly better for ΔglgA1ΔglgA2 mutant. Genome analysis revealed the presence of glgA1-like genes in all methanotrophs of the Gammaproteobacteria and Verrucomicrobia, while only a very few methanotrophic representatives of the Alphaproteobacteria possessed these determinants of glycogen biosynthesis. The glgA2-like genes were present only in genomes of gammaproteobacterial methanotrophs with predominantly halo- and thermotolerant phenotypes. The role of glycogen in terms of energy reserve is discussed.

A High Step-Down SiC-Based T-Type LLC Resonant Converter for Spacecraft Power Processing Unit

A spacecraft power processing unit (PPU) is utilized to convert power from solar arrays or electric batteries to the payload, including electric propulsion, communication equipment, and scientific instruments. Currently, a high-voltage converter is widely applied to the spacecraft PPU to improve power density and save launch weight. However, the high voltage level poses challenges such as high step-down ratios and high power losses. To achieve less conduction loss, a SiC-based T-type three-level (TL) LLC resonant converter is proposed. To further broaden the gain range and achieve high step-down ratios, a variable frequency and adjustable phase-shift (VFAPS) modulation scheme is proposed. Meanwhile, the steady-state time-domain model is established to elaborate the operation principles and boundary conditions for soft switching. Furthermore, the optimal resonant element design considerations have been elaborated to achieve wider gain range and facilitate easier soft switching. Furthermore, the numerical solutions for switching frequency and phase shift (PS) angle under each specific input could be figured out. Finally, the effectiveness of this theoretical analysis is demonstrated via a 500-W experimental prototype with 650∼950-V input and constant output of 48-V/11-A.

Natural Polyhydroxyalkanoates—An Overview of Bacterial Production Methods

Polyhydroxyalkanoates (PHAs) are intracellular biopolymers that microorganisms use for energy and carbon storage. They are mechanically similar to petrochemical plastics when chemically extracted, but are completely biodegradable. While they have potential as a replacement for petrochemical plastics, their high production cost using traditional carbon sources remains a significant challenge. One potential solution is to modify heterotrophic PHA-producing strains to utilize alternative carbon sources. An alternative approach is to utilize methylotrophic or autotrophic strains. This article provides an overview of bacterial strains employed for PHA production, with a particular focus on those exhibiting the highest PHA content in dry cell mass. The strains are organized according to their carbon source utilization, encompassing autotrophy (utilizing CO2, CO) and methylotrophy (utilizing reduced single-carbon substrates) to heterotrophy (utilizing more traditional and alternative substrates).

Indonesia's Movement to Become the Main Player in The Electric Vehicle (EV) Market in Southeast Asia

This article discusses Indonesia's position in the electric vehicle market with a focus on investment from multinational companies such as Hyundai. Globalization plays an important role in the development of the electric vehicle industry, with the aim of reducing pollution and exhaust emissions. Multinational companies are often involved in the production of environmentally friendly vehicles as part of efforts towards a green economy. Through descriptive qualitative research methods, this research describes the relationship between state policies and the behavior of investment actors in the phenomenon of global capitalism in globalization and its impact on the electric vehicle market in Indonesia. With investment from multinational companies, Indonesia is expected to become the leading electric car battery producer in ASEAN. The steps and strategies for cooperation between Indonesia and Hyundai in developing the electric car battery industry are also discussed in this article.

Hazard comparison of thermal runaway of electric marine battery cabinet under different trigger modes

Currently, the transportation industry, especially shipping, is still accompanied by serious carbon emissions and pollution. Electric ships are the most promising way to solve this problem. However, the application of electric ships in maritime affairs also faces many technical difficulties. This paper studies the heat generation and heat transfer in electric Marine battery cabinets (EMBC). Based on the Multi-Scale and Multi-Domain (MSMD) solution method, this study uses the Newman, Tiedemann, Gu, and Kim (NTGK) battery model to solve the thermal runaway propagation (TRP) of the EMBC, and then makes a visual analysis of the TRP of the EMBC with the three-layer Battery module (BM) structure. Furthermore, the TRP of the three-layer BM is compared based on three different triggering modes. Through analysis and comparison, it is found that among the three TR triggering modes: single battery heating, heat source at the bottom of the module, and heat source at the top. The first mode corresponds to a maximum heat release (HR) of 214.7 GJ, while the third mode exhibits a minimum HR of 212.3 GJ. Furthermore, the maximum temperature reached by the battery under the third mode is 1568 K, which is lower than that achieved in the other two modes. Additionally, it should be noted that the second mode has a higher maximum HR rate of 5772 GW/m3 compared to the third mode. The TR hazard resulting from heating at the bottom of the battery module outweighs that caused by heating at the top, without taking into account human-induced heating factors. The propagation of TR triggered by a single heat source throughout the EMBC can be inhibited within 226 s in the same layer, and prevented from spreading to the remaining layers for up to 596 s. In the present study, a new insight is presented to reveal the TR characteristics of the EMBC under different triggering modes, and quantify the TR duration.

Development of an electric drive for personal light electric vehicles

Problem. The article addresses the challenge of enhancing inclusive mobility and environmental cleanliness by developing a traction electric drive for personal light electric vehicles. A study was conducted on modern electric drive systems for personal light electric vehicles. Goal. The aim is to boost inclusive mobility and environmental cleanliness through the development of a traction electric drive for a personal light electric vehicle, specifically based on a tricycle. Methodology. The methodology involves scientific analysis and synthesis of traction electric drives for electric vehicles. An assessment of the nominal capacity of the battery module from the Nissan Leaf electric car was conducted using both partial discharge procedures and the Leaf Spy Pro program. Results. Based on an analysis of existing electric drive systems, a traction electric drive for a tricycle was developed. A functional diagram of the electric bicycle drive was generated. A control system for a sensorless brushless motor was developed, determining rotor position by measuring EMF in the free phase. This led to the creation of a stable voltage electrical circuit with a virtual midpoint. The tricycle's electric drive utilizes two 10-inch motor wheels on the rear wheels, enabling high speed and efficiency. Controllers specifically designed for electric wheel motors with a power of 350 W were selected to control the traction electric drive. Modules from the 2015 Nissan Leaf electric car's battery, which had depleted 20% of their capacity, were chosen to power the electric drive. The battery health status is 77.95%. A model of the battery's electrical equivalent circuit was constructed, and partial discharge graphs of the Nissan Leaf battery module were analyzed. Originality. The results provide a comprehensive insight into the development of a traction electric drive for personal light electric vehicles, using a tricycle as an example. Practical value. The research led to the development of an electric drive for a three-wheeled vehicle, with two motor wheels of 350 W nominal power each. The power supply voltage ranges from 36 V to 48 V, powered by six battery modules from the Nissan Leaf electric car, totaling 48 V. The energy capacity of one battery module is 0.3898 kWh, resulting in a total energy capacity of 2.3388 kWh for the vehicle's battery. However, the realizable capacity does not exceed 1.871 kWh, providing a travel distance of approximately 75 km on one battery charge. These findings demonstrate the feasibility of reusing batteries from electric cars with diminished capacity to power light electric vehicles. The results are relevant for scientific and technical professionals involved in electric vehicle development.

Functional analysis of speed, battery pack capacities and chargers of small electric ships

Electric propulsion refers to propulsion using a combination of an electric motor and batteries. Electric motors powered by batteries represent a significant solution within the broader context of sustainability, energy efficiency, and technological advancement. As energy containers, batteries are characterized by low energy and power density and are currently not considered suitable for use on large displacement ships. Consumption of electric ships depends on numerous factors and the performance of the vessel's energy system requires great attention. The basic limitations are the ship’s size and speed, the built-in capacity of the batteries, charging infrastructure, and sailing distance. These limitations are discussed and justified in two case studies in which the existing diesel-powered ships are replaced with electric ones.

Inhibition effect of inert gas jet on gas and hybrid explosions caused by thermal runaway of lithium-ion battery

When lithium-ion batteries undergo thermal runaway in a confined space, the released gases and/or vapors or dust particles can lead to an explosion. An 8L cylindrical experimental vessel was constructed to study the inert effect of inert gases on battery-vented gas (BVG) in a confined vessel. Firstly, the inhibition effect and inert mechanism of CO2 and N2 on BVG explosion were analyzed by experiments and simulation software. The results show that the inert effect of CO2 on the BVG is significantly better than that of N2. This is because CO2 is not only better than N2 in physical explosion inhibition, but also participates in the chemical reaction. Secondly, the effect of the release of high-pressure CO2 gas on the explosion of the BVG in a closed container was simulated, showing that when the BVG is near the lower explosive limit, the CO2 jet will significantly increase the rate of explosion pressure rise of the BVG. This suggests that the inhibition effect of the CO2 jet is not as good as in premixed conditions. Finally, it is found that the inhibition effect of CO2 on the hybrid explosion is better than that of CO2 jet on the BVG. Since CO2 makes oxygen insufficient, leading to a reduction in the amount of graphite dust burned. The graphite dust and CO2 have a synergistic inhibition effect on the hybrid explosion. The above findings can provide a reference for the lithium-ion battery explosion inhibition method in the process industry.

World experience of legislative regulation for Lithium-ion electric vehicle batteries considering their second-life application in power sector

Understanding and incorporating global regulatory experiences and standards related to battery management is of greatest importance, particularly when considering the rapid evolution of the electric vehicle (EV) market and its implications for energy storage and sustainability. This is especially relevant for Ukraine, where the burgeoning secondary market for EVs and a keen interest in renewable energy sources underscore the need for proactive policy-making and standardization to address the challenges of battery second life and recycling. This article delves into the role of Electric Vehicle Lithium-Ion batteries within the ambit of the circular economy, underscoring the significance of legislative frameworks across the globe with a particular focus on European initiatives in light of Ukraine's EU integration ambitions. This encompasses extending battery life through recycling and repurposing, thereby ensuring both economic viability and minimal environmental footprint. The narrative outlines the varied legislative landscapes internationally, noting the differences in strategies from Asia's technological and safety emphasis to Europe's robust regulatory directives aimed at battery lifecycle management. In Europe, the drive towards sustainable battery utilization is marked by comprehensive policies like the EU Battery Directive and the emerging Regulation on Batteries and Waste Batteries, which set forth ambitious recycling targets and introduce innovative concepts like the battery passport. Drawing from this global overview, the article posits a set of recommendations for Ukraine, suggesting the development of extensive battery management legislation, adoption of European standards to smooth the path towards EU membership, investment in recycling infrastructures, fostering of public-private partnerships, and public awareness initiatives. These recommendations are designed to elevate Ukraine's position in the sustainability, promoting environmental stewardship and economic competitiveness. The growing importance of secondary lithium-ion batteries for electric vehicles in supporting and harmonizing renewable energy sources is emphasized, and accordingly, the need for adequate legislation and standardization to support a closed-loop economy. Keywords: Lithium-Ion Batteries, Second-Life Application, EV Battery Life Cycle, Circular Economy, Repurpose, Reuse, Recycling, Standards, Regulation, Legislation.

High capacities of carbon capture and photosynthesis of a novel organic carbon-fixing microalgae in municipal wastewater: From mutagenesis, screening, ability evaluation to mechanism analysis

The development of wastewater treatment processes capable of reducing and fixing carbon is currently a hot topic in the wastewater treatment field. Microalgae possess a natural carbon-fixing advantage, and microalgae that can symbiotically coexist with indigenous bacteria in actual wastewater attract more significant attention. Ultraviolet (UV) mutagenesis and dissolved organic carbon (DOC) acclimation were applied to strengthen the carbon-fixing performance of microalgae in this study. The mechanisms associated with microalgal water purification ability, gene regulation at the molecular level and photosynthetic potential under different trophic modes resulting from carbon fixation and transformation were disclosed. The superior performance of Chlorella sp. MHQ2 was eventually screened out among a large number of mutants generated from 3 wild-type Chlorella strains. Results indicated that the dry cell weight of the optimal species Chlorella sp. HQ mutant MHQ2 was 1.91 times that of the wild strain in the pure algal system, more carbon from municipal wastewater (MW) were transferred to the microalgae and re-entered into the biological cycle through resource utilization. In addition, COD, NH3-N and TP removal efficiencies of MW by Chlorella sp. MHQ2 were found to increase to 95.8% (1.1-times), 96.4% (1.4-times), and 92.9% (1.2-times), respectively, under the extra DOC supply and the assistance of indigenous bacteria in the MW. In the transcriptome analysis of the logarithmic phase, the glycolytic pathway was inhibited, and the pentose phosphate pathway was mainly carried out for microalgal life activities, further promoting efficient energy utilization. Upon analysis of carbon capture capacity and photosynthetic potential in trophic mode, the addition of NaHCO3 increased the photosynthetic rate of Chlorella sp. MHQ2 in mixotrophy whereas it was attenuated in autotrophy. This study could provide a new perspective for the study of resource utilization and microalgae carbon- fixing mechanisms in the actual wastewater treatment process.

Structural optimization of thermal management system for bionic liquid cold battery based on fuzzy grey correlation analysis

An energy-efficient battery thermal management system with efficient enhanced heat transfer characteristics, low power consumption and backflow inhibition performance is of great importance for electric vehicle power batteries. Based on the design of the Tesla valve and inspired by bionics, a new type of bionic blade-like mini-channel liquid cold plate with high efficiency, low power consumption and certain anti-reverse flow performance was proposed. Firstly, the initial liquid-cooled plate thermal simulation model at 5C discharge was established by CFD method and its reliability was verified by experiment. Then, orthogonal tests and fuzzy correlation analysis (FGRA) were used as evaluation methods to analyze the effects of four structural parameters (inner angle α, circumcenter angle θ1, circumcenter angle θ2, and channel height d) on the average temperature, heat transfer coefficient, and friction coefficient. The results show that the variation of the channel height d had the highest degree of influence on the mean temperature (Tave) and friction coefficient f, and that the internal angle α had the highest correlation with the heat transfer coefficient h. Finally, based on the optimization results, a better model within the range of values of each factor was obtained. When α = 25°, θ1 = 90°,θ2 = 75°, and d = 1.2 mm, Nu was increased by 0.932 (95.08 %), and ΔP was decreased by 501.686 Pa (84.74 %).The results of the optimization were shown in the following table.

Unlocking the potential of depleted dry batteries: A dual-purpose approach for waste mitigation and sustainable energy production

Electronic-waste (e-waste) poses a serious environmental challenge due to the increasing consumption and disposal of electronic devices. In the present work a novel method is proposed to repurpose e-waste and bio-waste into a single-chamber and mediator-less microbial fuel cells using dead, non-rechargeable D-type dry batteries. The carbonaceous material inside the dry batteries was replaced with kitchen waste sludge, which served as the substrate. The outer zinc casing was also reused as the anode and the carbon rod as the cathode. Treating the kitchen waste sludge with dilute nitric acid improved the performance of the microbial fuel cells by enhancing the biodegradability and conductivity of the substrate. The untreated microbial fuel cells produced a maximum power density of 15.0 mW/kg at a maximum current density of 50.0 mA/kg, while the treated microbial fuel cells achieved 67.0 mW/kg at 178.0 mA/kg. The main mechanism behind the working of the device is the combined action of galvanic and microbial processes, which synergistically generate electricity from e-waste and bio-waste. Moreover, when four treated microbial fuel cells were connected in series, a high open circuit voltage of 3.3 V was achieved. These microbial fuel cells stand out as eco-conscious and lightweight alternatives to conventional dry batteries, presenting an environmentally sustainable solution for waste management and clean energy production.

Techno–economic and environmental impact analysis of electric two-wheeler batteries in India

Abstract This paper presents a comprehensive techno–economic and environmental impact analysis of electric two-wheeler batteries in India. The technical comparison reveals that sodium-ion (Na-ion) and lithium-ion (Li-ion) batteries outperform lead–acid batteries in various parameters, with Na-ion and Li-ion batteries exhibiting higher energy densities, higher power densities, longer cycle lives, faster charge rates, better compactness, lighter weight and lower self-discharge rates. In economic comparison, Na-ion batteries were found to be ~12–14% more expensive than Li-ion batteries. However, the longer lifespans and higher energy densities of Na-ion and Li-ion batteries can offset their higher costs through improved performance and long-term savings. Lead–acid batteries have the highest environmental impact, while Li-ion batteries demonstrate better environmental performance and potential for recycling. Na-ion batteries offer promising environmental advantages with their abundance, lower cost and lower toxic and hazardous material content. Efficient recycling processes can further enhance the environmental benefits of Na-ion batteries. Overall, this research examines the potential of Na-ion batteries as a cheaper alternative to Li-ion batteries, considering India’s abundant sodium resources in regions such as Rajasthan, Chhattisgarh, Jharkhand and others.

Optimal energy storage system selection for future cost-effective green hydrogen production: Integrating techno-economic, risk-based decision making, and cost projections

This study conducts technical, economic, and safety analysis of a green hydrogen production system consisting of a 1000 kWp photovoltaic cell, 3 options of energy storage namely lead carbon (PbC), lithium-ion (Li-ion), and repurposed lithium-ion (2nd Life Li-ion) battery, and an electrolyzer. Firstly, the system is optimized to maximum hydrogen production by adjusting equipment capacity and capacity factors, informed by a 1-h resolution solar energy generation profile. This optimization yields insights into the system's yearly operational dynamics. Techno-economic analysis was conducted to estimate the levelized cost of hydrogen (LCOH) from 2020 to 2050, additionally, uncertainty analysis using Monte-Carlo simulation to estimate the range of uncertainty in LCOH projection from 2020 to 2050 was performed. Furthermore, a quantitative risk analysis, utilizing the process route index metric, evaluates the risk of battery explosions. Finally, this study employs multi-criteria decision-making to choose the best energy storage technology to produce green hydrogen from economic and safety factors. The result indicates that in 2020, the PbC battery emerged as the most cost-effective option. However, over time, both lithium batteries became the cheapest option with almost similar trends. In terms of explosion hazard, the analysis shows that the PbC battery is a safer option for stationary energy storage. When both aspects are considered, the preferred battery option is almost certainly PbC over the years, but in extreme cases where the decision-maker places significant emphasis on economic factors both Li-ion options may become preferable.

Enhancing astaxanthin accumulation through the expression of the plant-derived astaxanthin biosynthetic pathway in Dunaliella salina

Dunaliella salina, a microalga that thrives under high-saline conditions, is notable for its high β-carotene content and the absence of a polysaccharide cell wall. These unique characteristics render it a prime candidate as a cellular platform for astaxanthin production. In this study, our initial tests in an E. coli revealed that β-ring-4-dehydrogenase (CBFD) and 4-hydroxy-β-ring-4-dehydrogenase (HBFD) genes from Adonis aestivalis outperformed β-carotene hydroxylase (BCH) and β-carotene ketolase (BKT) from Haematococcus pluvialis counterparts by two-fold in terms of astaxanthin biosynthesis efficiency. Subsequently, we utilized electroporation to integrate either the BKT gene or the CBFD and HBFD genes into the genome of D. salina. In comparison to wild-type D. salina, strains transformed with BKT or CBFD and HBFD exhibited inhibited growth, underwent color changes to shades of red and yellow, and saw a nearly 50% decline in cell density. HPLC analysis confirmed astaxanthin synthesis in engineered D. salina strains, with CBFD + HBFD-D. salina yielding 134.88 ± 9.12 μg/g of dry cell weight (DCW), significantly higher than BKT-D. salina (83.58 ± 2.40 μg/g). This represents the largest amount of astaxanthin extracted from transgenic D. salina, as reported to date. These findings have significant implications, opening up new avenues for the development of specialized D. salina-based microcell factories for efficient astaxanthin production.

Formulation of biogenic fluorescent pigmented PHB nanoparticles from Rhodanobacter sp. for drug delivery.

Biogenic nanoparticles (NPs) have emerged as promising therapeutic formulations in effective drug delivery. Despite of various positive attributes, these NPs are often conjugated with various cytotoxic organic fluorophores for bioimaging, thereby reducing its effectiveness as a potential carrier. Herein, we aim to formulate biogenic fluorescent pigmented polyhydroxybutyrate (PHB) NPs from Rhodanobacter sp. strain KT31 (OK001852) for drug delivery. The bacterial strain produced 0.5g L-1 of polyhydroxyalkanoates (PHAs) from 2.04g L-1 of dry cell weight (DCW) under optimised conditions via submerged fermentation. Further, structural, thermal, and morphological charactersiation of the extracted PHAs was conducted using advance analytical technologies. IR spectra at 1719.25cm-1 confirmed presence of C = O functional group PHB. NMR and XRD analysis validated the chemical structure and crystallinity of PHB. TG-DTA revealed Tm (168 °C), Td (292 °C), and Xc (35%) of the PHB. FE-SEM imaging indicated rough surface of the PHB film and the biodegradability was confirmed from open windro composting. WST1 assay showed no significant cell death (> 50%) from 100 to 500µg/mL, endorsing non-cytotoxic nature of PHB. PHB NPs were uniform, smooth and spherical with size distribution and mean zeta potential 44.73nm and 0.5mV. IR and XRD peaks obtained at 1721.75cm-1 and 48.42Å denoted C = O and crystalline nature of PHB. Cell proliferation rate of PHB NPs was quite significant at 50µg/mL, establishing the non-cytotoxic nature of NPs. Further, in vitro efficacy of the PHB NPs needs to be evaluated prior to the biomedical applications.