Sustainable Production Processes Research Articles

Physico-chemical properties of macadamia nut shell post-gasification residues and potential agricultural application

In–depth information about the characteristics and potential use of post-gasification residues is the key to unlock the sustainability potential of biomass gasification. This study aimed to explicate the physico-chemical properties of residues after the gasification of macadamia nut shell using a commercial gasifier. The results revealed an important amount of carbon content remained in the residues, marking the low conversion efficiency of the process. The obtained residues were deemed unsuitable for use as adsorbents due to low surface areas with non-porous structures. However, the surface of the residues contained multiple carboxyl and hydroxyl functional groups. Also, a remarkable amount of K (up to 86 wt% of the char’s total inorganic elements) was observed to be evenly distributed on the char surface. The results solidified the possibility of utilizing the residues as bio-fertilizers, and provided essential data for the development of sustainable energy production processes using macadamia nut shell for gasification.

Density‐Functional Theory Studies on Photocatalysis and Photoelectrocatalysis: Challenges and Opportunities

Density‐functional theory (DFT) is pivotal in the advancement of photocatalysis and photoelectrocatalysis. Its capability to explore electronic structures of materials contributes significantly to clarifying the mechanisms of photocatalytic (PC) and photoelectrocatalytic (PEC) processes. DFT calculations enable a deeper understanding of how these processes work at a molecular level, which is essential for designing versatile photocatalysts and photoelectrodes and optimizing reaction pathways. In this perspective, key PC and PEC applications, such as H2 production, CO2 reduction, dye degradation, and N2 reduction, where DFT is instrumental in optimizing materials designs and reaction pathways, are highlighted. Exploration on the synergy between experimental research and DFT calculations is highlighted, which is crucial for the development of efficient and environmentally friendly energy solutions. The discussion further extends to challenges and future directions, emphasizing the need for incorporating factors, including discrepancy in scale, light illumination, electrolyte presence, and applied bias, into DFT calculations, to achieve a more comprehensive understanding of PC and PEC systems. In this perspective, it is aimed to provide a holistic view of the current state and potential advancements in photocatalyst and photoelectrode modeling, thereby guiding future research toward more effective and sustainable energy and chemical production processes in PC and PEC systems.

A sustainable process for electrochemical production of 2-Iodosylbenzoic acid

Herein, an environmentally friendly, scalable and highly efficient process for production of 2-iodosylbenzoic acid, a well-established hypervalent iodine oxidant is reported. It is based on anodic oxidation of 2-iodobenzoic acid in anhydrous AcONa-AcOH electrolyte followed by simple work-up of solid product. In particular, a benefit of the developed electrochemical process is absence of any chemical oxidant, application of environmentally benign solvent, high Faradaic efficiency and product yield. The process on the anode side combines anodic oxidation of reactant to the desired product with separation process, i.e. removal of Na+ cation from the anolyte through a cation-exchange membrane leading to drop of AcONa concentration. Consequently, the product of high purity can be obtained simply by filtering the anolyte solution followed by drying the filtration cake. Interestingly, no washing by organic solvents is required. Moreover, both anolyte filtrate and catholyte can be reused multiple times. Energy and material balance and cost and environmental footprint analysis showed benefits of the developed process and suggested clear strategy towards further reduction of the product cost and, in particular, significant decrease of a generated waste amount.

Study on ammonia transport and separation in Aquivion® perfluoro sulfonated acid membranes

The present study reports the results of a series of sorption and permeation tests of pure ammonia as well as nitrogen and hydrogen carried out on Aquivion C87-05 (short-side chain perfluoro sulfonic acid ionomer). Such material is indeed of interest for possible applications in sustainable processes for ammonia production, either as base material for polymer electrolyte membranes in low-temperature electrochemical ammonia synthesis or as a membrane for effective product separation.NH3, N2, and H2 permeation tests are performed at different temperatures (20, 35, and 50 °C) and both in dry and humid conditions (R.H. up to 80%), aiming to assess the influence of these parameters on the resulting permeabilities, while ammonia sorption is inspected at the same temperatures, and pressures up to near saturation conditions.Pure ammonia permeability reached outstanding values around 7000 Barrer in dry Aquivion membranes, revealing an increasing trend with upstream pressure, while it decreased with temperature. The same behavior is recorded for NH3 solubility, indicating that sorption drives the ammonia transport through the membrane.The obtained separation performances are found to be significantly better than those of other polymeric membranes proposed for the same separations, as compared to a permeability-selectivity plot.

Sustainable manufacturing production process monitoring and economic benefit analysis based on IoT technology

Sustainable manufacturing production process monitoring and economic benefit analysis based on IoT technology

Pilot Tests of Pre-Reduction in Chromium Raw Materials from Donskoy Ore Mining and Processing Plant and Melting of High-Carbon Ferrochromium

Experiments were conducted to pilot the initial reduction in chromium raw materials using the innovative Hoganas technology in a tunnel furnace. To simulate the process, a gas-fired bogie hearth furnace was employed. Technological containers made of silicon carbide crucibles were utilized. Sixteen different combinations of ore and coal mixtures were employed for the initial reduction process. Their total mass was more than 20 tons. Their heat treatment was performed at different temperatures and durations. During the pilot tests, the possibility of achieving chromium metallization was confirmed. Thus, it explains the application of a pre-reduction instead of the sintering or charge heating before the ferrochromium melting, i.e., the power consumption is minimized during the final remelting of the product in DC furnaces. The pilot melting of three batches of the pre-reduced chromium raw materials with various chromium metallization degrees has been tested in the ore-smelting furnace at Zh. Abishev Chemical–Metallurgical Institute (Karaganda). The capacity was 0.2 MVA. To evaluate the technical and economic efficiency of remelting pre-reduced chromium raw materials in commercial DC furnaces, a specific batch of primary ingredients for producing high-carbon ferrochromium, including chromite ore, coke, and quartz flux, was successfully melted in a segregated phase. As a result of the study, it was found that the specific energy consumption for melting high-carbon ferrochromium in the pilot furnace depends on the chromium metallization degree. The researchers tested a range of chromium metallization degrees from 0 to 65% and determined the corresponding specific energy consumption for each degree. Using the data obtained from the study, the researchers were able to assess the melting indexes of high-carbon ferrochromium in a larger 72 MW furnace. They found that by using a pre-reduced product with a chromium metallization degree of 65%, it was possible to reduce the specific energy consumption by half, to around 3.4 MW·h per ton of chromium. Overall, this study highlights the importance of considering the chromium metallization degree when determining the specific energy consumption for melting high-carbon ferrochromium. By optimizing the metallization degree, significant energy savings can be achieved, leading to more efficient and sustainable production processes.

Modeling of a Biomass-Based Energy Production Case Study Using Flexible Inputs with the P-Graph Framework

In this work, a modeling technique utilizing the P-Graph framework was used for a case study involving biomass-based local energy production. In recent years, distributed energy systems gained attention. These systems aim to satisfy energy supply demands, support the local economy, decrease transportation needs and dependence on imports, and, in general, obtain a more sustainable energy production process. Designing such systems is a challenge, for which novel optimization approaches were developed to help decision making. Previous work used the P-Graph framework to optimize energy production in a small rural area, involving manure, intercrops, grass, and corn silage as inputs and fermenters. Biogas is produced in fermenters, and Combined Heat and Power (CHP) plants provide heat and electricity. A more recent result introduced the concept of operations with flexible inputs in the P-Graph framework. In this work, the concept of flexible inputs was applied to model fermenters in the original case study. A new implementation of the original decision problem was made both as a Mixed-Integer Linear Programming (MILP) model and as a purely P-Graph model by using the flexible input technique. Both approaches provided the same optimal solution, with a 31% larger profit than the fixed input model.

Metabolic control analysis enabled the improvement of the L-cysteine production process with Escherichia coli

L-cysteine is an amino acid with relevance to the pharmaceutical, food, feed, and cosmetic industry. The environmental and societal impact of its chemical production has led to the development of more sustainable fermentative L-cysteine production processes with engineered E. coli based on glucose and thiosulfate as sulphur source. Still, most of the published processes show low yields. For the identification of further metabolic engineering targets, engineered E. coli cells were withdrawn from a fed-batch production process, followed by in vivo metabolic control analysis (MCA) based on the data of short-term perturbation experiments, metabolomics (LC–MS), and thermodynamic flux analysis (TFA). In vivo MCA indicated that the activities of the L-cysteine synthases of the cells withdrawn from the production process might be limiting, and we hypothesised that the L-cysteine precursor O-acetylserine (OAS) might be exported from the cells faster than it took to transform OAS into L-cysteine. By increasing the expression of the L-cysteine synthases, either sulfocysteine synthase or L-cysteine synthase, which transform OAS into L-cysteine, an improvement of up to 70% in specific L-cysteine productivity and up to 47% in the final L-cysteine concentration was achieved in standardised fed-batch processes thereby increasing the yield on glucose by more than 85 to 9.2% (w/w).Key points• Metabolic control analysis was applied to analyse L-cysteine production with E. coli• OAS export was faster than its transformation to L-cysteine• Overexpression of L-cysteine synthases improved L-cysteine productivity and yield

Co-Valorisation Energy Potential of Wastewater Treatment Sludge and Agroforestry Waste

The growing demand for sustainable and environment-friendly energy sources resulted in extensive research in the field of renewable energy. Biomass, derived from organic materials such as agricultural waste, forestry products, and wastewater treatment plant (WWTP) sludge, holds great potential as a renewable energy resource that can reduce greenhouse gas emissions and offer sustainable solutions for energy production. This study focused on diverse biomass materials, including sludge from WWTPs, forest biomass, swine waste, cork powder, and biochar. Chemical and physicochemical characterizations were performed to understand their energy potential, highlighting their elemental composition, proximate analysis, and calorific values. Results showed that different biomasses have varying energy content, with biochar and cork powder emerging as high-energy materials with net heating values of 32.56 MJ/kg and 25.73 MJ/kg, respectively. WWTP sludge also demonstrated considerable potential with net heating values of around 14.87 MJ/kg to 17.44 MJ/kg. The relationships between biomass compositions and their heating values were explored, indicating the significance of low nitrogen and sulphur content and favourable carbon, hydrogen, and moisture balances for energy production. Additionally, this study looked into the possibility of mixing different biomasses to optimize their use and overcome limitations like high ash and moisture contents. Mixtures, such as “75% Santo Emilião WWTP Sludge + 25% Biochar,” showed impressive net heating values of approximately 21.032 MJ/kg and demonstrated reduced emissions during combustion. The study’s findings contribute to renewable energy research, offering insights into efficient and sustainable energy production processes and emphasizing the environmental benefits of biomass energy sources with low nitrogen and sulphur content.

Antecedents of cloud-based financial information systems usage: An integrated model

The recent progress of Financial Information System (FIS) has significantly affected businesses’ sustainable production process. Businesses generally employ FIS to automate their operational procedures and increase their corporate efficiencies through improvement in output quality and sustainability. The performance of FIS has been attributed to its key success criteria. Accordingly, this study examined antecedents of FIS intention to use among Small and Medium-Size Enterprises (SMEs) in Jordan at individual level, with specific focus on the acceptance and use of FIS among accounting department employees. Based on 436 respondents from Jordanian SMEs, results showed an impact of COVID-19 risk, trust, performance expectancy, and perceived severity on the intention to use FIS, whereas effort expectancy and perceived vulnerability showed no impact on the intention to use FIS among Jordanian SMEs.

Compressed fluid-based technology for downstream isolation of bluish anthocyanin-derived pigments obtained from blueberry surplus.

A dynamic compressed fluid-based separation process combining carbon dioxide and ethanol was explored to isolate portisins previously hemi-synthesized from blueberry surplus anthocyanins. The influence of process parameters such as pressure (100-500 bar), temperature (40-60 °C), and ethanol content in the compressed fluid mixture (20-50 wt%) on extraction yield, portisins yield, and portisins content in the extract was investigated. The two-step isolation process includes (1) a first step at 100 bar, 60 °C, and 20 wt% ethanol content in the compressed fluid mixture to remove the low polarity compounds; and (2) a second step at 500 bar, 40 °C, and 100 wt% ethanol to recover portisins, resulting in a 1.5-fold increase in portisins content. The performance of the two-step separation process was compared to centrifugal partitional chromatography and conventional reverse phase liquid chromatography already reported in terms of portisins content in the extract, process throughput, process efficiency, and total solvent used. The two-step separation process decreased the total solvent used, although with a decrease in the throughput and efficiency. Nevertheless, the choice of the best separation technology depends on the application, as these techniques result in different portisins purities. Overall, this study contributed to a scalable and more sustainable process for natural colorant production, specifically focusing on blue pigments, with several industrial applications.

Continuous reciprocating plate and packed bed multiphase reactors in biodiesel production: Advancements and challenges

Biodiesel, a renewable and environmentally friendly alternative to conventional fossil fuels, has gained significant attention over the last two decades. Continuous production of biodiesel offers efficiency, productivity, and scalability advantages. This paper provides a concise overview of continuous reactor systems for biodiesel production, focusing on two specific systems-the reciprocating plate reactor and the packed bed reactor-subjects of the authors' extensive research. A thorough comparison of these reactors, spanning biodiesel yield, reaction kinetics, and conversion efficiency, underscores their advantages. The reciprocating plate reactor demonstrates superior mixing characteristics, which improve mass transfer and reaction kinetics. Conversely, the packed bed reactor offers a higher catalyst-to-feedstock ratio and longer residence time, enhancing conversion efficiency. Both reactors exhibit favourable performance for continuous biodiesel production. This research can contribute to understanding continuous biodiesel production using innovative reactor designs. The comparative analysis between the reciprocating plate and packed bed reactors offers valuable insights for process optimization and reactor selection based on specific requirements such as feedstock availability, reaction kinetics, and economic considerations. These insights pave the way for the implementation of sustainable and efficient biodiesel production processes in the future.

Chemistry of the iron-chlorine thermochemical cycle for hydrogen production utilizing industrial waste heat

This research presents an inventive thermochemical cycle that utilizes a reaction between iron and HCl acid for hydrogen production. The reaction occurs spontaneously at room temperature, yielding hydrogen and a FeCl2 solution as a by-product. Exploring the thermal decomposition of the FeCl2 by-product revealed that, at conditions suitable for utilization of low-temperature industrial waste heat (250 °C), chlorine gas formation can be circumvented. Instead, the resulting by-product is HCl, which is readily soluble in water, facilitating direct reuse in subsequent cycles. The utilization of low-temperature industrial heat not only optimizes resource utilization and reduces operational costs but also aligns with environmentally sustainable production processes. From the kinetic studies the activation energy was calculated to be 45 kJ/mol and kinetics curves were constructed. They showed significant kinetics at room temperature and above but rapid decrease towards lower temperatures. This is important to consider during real-scale technology optimization. The theoretical overall energy efficiency of the cycle, with 100% and 70% heat recuperation, was calculated at 68.8% and 44.8%, respectively. In practical implementation, considering the efficiency of DRI iron reduction technology and free waste heat utilization, the cycle achieved a 41.7% efficiency. Beyond its energy storage capabilities, the Iron-chlorine cycle addresses safety concerns associated with large-scale hydrogen storage, eliminating self-discharge, reducing land usage, and employing cost-effective storage materials. This technology not only facilitates seasonal energy storage but also establishes solid-state energy reserves, making it suitable for balancing grid demands during winter months using excess renewable energy accumulated in the summer.

SUSTAINABILITY APPROACHES IN DENIM PRODUCTS AND PRODUCTION PROCESSES

Sustainability in denim refers to the practices implemented to reduce the environmental, economic and social impacts of the denim production process and these practices are divided into two as product and production process. Sustainable denim product practices include various approaches such as using environmentally friendly, organic materials and recycled denim. In the sustainable production process, there are more sustainable alternatives such as desizing with amylase enzyme, mercerization with the best available techniques, bleaching with enzyme, ozone and laser technologies, washing with natural resources and water reduction technologies. This study aims to explain the sustainable product and production process that can reduce waste, water and energy consumption, using environmentally friendly raw materials, recycling and reuse.

PREDICTIVE MAINTENANCE OF A FLEXIBLE PRODUCTION LINE IMPLEMENTED IN MATLAB

In the latest years, the need of new technologies in the industrial environment has increased due to the need of a more cost efficient, resilient, and sustainable production process. One of the main issues that is addressed in this research work is the lack of a technology that allows prediction and prevention of the breakdowns of a production line using digital models and artificial intelligence to take the best decisions based on real-time data. This paper presents a method for collecting data from the production line and feed these data to a database used by the Digital Twin model created in Matlab Predictive Maintenance Toolbox in which, based on this data, a decision about the maintenance activities required will be taken. This approach generates significant value by assisting maintenance engineers in pinpointing the precise timing for equipment maintenance. This capability directly contributes to reducing production line downtime and minimizing failures. Also, the Digital Twin model can be used to enable and test adjustments to the parameters of the production line equipment in order to determine the impact of this changes of the production process without interfering with the production process itself.

Efficient catalyst regeneration through solvent-based wax extraction for Co/Al2O3 Fischer-Tropsch catalysts

The regeneration of Fischer-Tropsch (FT) catalysts plays a crucial role in sustaining their catalytic activity and longevity in sustainable production processes. This research investigates the effectiveness of various solvents, including n-hexane, n-heptane, toluene, xylene, and the liquid fraction of FT products (LF-FT), for catalyst regeneration and extracting wax from the 15 wt%Co/Al2O3 catalyst. Toluene, with a unique combination of key parameters such as polarity, solubility, boiling point, aromatic structure, and chemical interactions, exhibited the highest wax removal efficiency of 90.6%. However, due to its 41 °C lower boiling point compared to toluene and very similar wax removal efficiency, n-hexane appears as a more energy-efficient and cost-effective option for this process. The regenerated catalysts showed comparable characteristics, including the textural properties (surface area, pore size, and pore volume), crystallinity, and reducibility, to fresh catalysts. The slightly lower reduction temperature in the regenerated catalyst indicates a higher possibility for the formation of cobalt active sites during the catalyst reduction process with hydrogen, leading to an increased potential for higher catalytic activity. The LF-FT, comprising paraffins, iso-paraffins, olefins, napthenes, and aromatics, provided a unique combination of aliphatic and aromatic moieties, enhancing the solubility of both polar and nonpolar components in FT wax and improving the wax removal efficiency to 91.5%. The higher boiling point and operating temperature of the LF-FT also contributed to its better performance. Efficient separation of hydrocarbons from solvents allowed for solvent reusability in subsequent FT wax removal cycles, making it advantageous for large-scale applications.

Electrochemical Analysis on Transition Metal Nitride Catalysts for Nitrogen Reduction Reaction

A versatile and sustainable process for ammonia production is needed to ensure a sustainable future for the growing global population, both with regards to fertilizer production as well as energy carrier. Theoretical simulations of transition metal nitride catalysts have demonstrated the possibilityof a nitrogen reduction reaction catalysis cycle on four transition metal nitrides, CrN, VN, ZrN and NbN.[1,2] Reproducible and reliable research and development approaches in the direction of electrochemical reduction of nitrogen towards ammonia are therefore of importance. An operando ammonia quantification methodology for electrochemical catalysis studies has been developed in-house and recently published [3]. Allowing for automatic, quantitative detection of aqueouos ammonia at the ppb level, within minutes from the sample preparation. We have now analyzed all four theoretically proposed TMNs, as well as rutile Niobium oxynitride (NbON) of several stochiometries as thin films on a conductive electrode substrate in ambient environment and aqueouos electrochemical system [3,4].Electrochemical analysis and ammonia quantification suggest NbON of specific stochiometry and ZrN to be promising catalyst candidates, while lacking stability in the environment of choice in these studies.Literature:[1] Y. Abghoui, A.L. Garden, J.G. Howalt, T. Vegge and E. Skúlason, Electroreduction of N2 to ammonia at ambient conditions on mononitrides of Zr, Nb, Cr, and V: A DFT guide for experiments. ACS Catalysis, 2016.6(2): p. 635.[2] Y. Abghoui, A.L. Garden, V.F. Hlynsson, S. Björgvinsdóttir, H. Ólafsdóttir and E.Skúlason, Enabling electrochemical reduction of nitrogen to ammonia at ambient conditions through rational catalyst design. Physical Chemistry Chemical Physics,2015.17(7): p. 4909.[3] F. Hanifpour, C.P. Canales, E.G. Fridriksson, A. Sveinbjörnsson, T.K. Tryggvason,E. Lewin, . H.D. Flosadóttir, Investigation into the mechanism of electrochemical nitrogen reduction reaction to ammonia using niobium oxynitride thin-film catalysts. Electrochimica Acta, 2022.403: p. 139551.[4] F. Hanifpour, C.P. Canales, E.G. Friðriksson, A. Sveinbjörnsson, T. Tryggvason, Y.Abghoui, . E. Skúlason, Operando Quanitification of ammonia produced from computationally derived transition metal nitride electro catalysts. Journal of Catalysis, 2022. 413: p.956

Free Standing Electrodes: From Roll Product to 41-Layer Pouch Cells

Processes to produce free standing electrodes for Lithium-Ion Batteries (LIB), using lithium iron phosphate (LFP) as active material for the cathode and artificial graphite for the anode, are being developed. The production of these electrodes is realized by using a slot die to produce a liquid film which solidifies in a precipitation bath and is wound up after moving through washing baths. This procedure consumes significantly less energy compared to conventional coating processes, as the drying needs are reduced, and the electrodes have a broader spectrum of use cases due to their high flexibility.In this work, the development process of the manufacturing procedures of pouch cells using free standing electrodes will be presented. This includes the characterization of the electrodes, usability trials with research pilot line equipment, and cycling tests of built pouch cells of up to more than 7 Ah per device.The screening of electrodes through cycling in coin cells showed a specific discharge capacity of > 120 mAhg-1 for 50 cycles at 0.2C.This innovative and sustainable electrode production process required adjustments throughout the whole production process of a LIB, starting with the slot die geometry to reduce thick edges of the released film. The electrodes’ surfaces were investigated regarding homogeneity and roughness using a digital microscope. Gas adsorptioneasurements showed the specific surface of cathodes at around 3.6 m²g-1. Challenges during calendaring of the free-standing electrodes included thickness deviations of the pristine electrodes and uneven tension throughout the width of the samples.After laminating the free-standing electrodes with current collectors, they were electrochemically and mechanically analysed. Therefore, additional adjustments had to be made to attach tabs on multiple layers of these flexible electrodes through a single ultrasonic welding spot. All electrodes were successfully processed inside a dry room (dew point < -40 °C) using industrially relevant pilot scale equipment (punching, stacking, electrolyte filling, sealing).The manufactured pouch cells all showed an initial OCV of around 400 mV and were formed prior to cycling. During three formation cycles at 0.1C, followed by a constant Voltage step, the two-layered pouch cells showed a specific discharge capacity of . These cells reached roughly 90 mAhg-1 of discharge capacity after 20 cycles at 0.2C, but higher C-rates reduced the capacity and cell life significantly. Measuring the cells’ resistance after cycling at 3.3 V using 10 measurement points at 1 kHz revealed the high inner resistance of > 2 Ohm. Post-mortem analysis revealed lithium deposition throughout the whole surface of the anode. In the following upscaling process, the number of layers was increased to 11 layers (2 Ah cells) and 41 layers (7 Ah cells). These pouch cells showed similar performances, specific discharge capacities of around 110 mAhg-1 during formation, but with decreased cycling capabilities at C-rates higher than 0.1C. The main cause for this behaviour is the high inner resistance of these cells.In this work we demonstrate that free-standing electrodes can be handled at pilot scale in a comparable manner as conventionally coated electrodes. The produced cells were all successfully cycled but showed higher inner resistances and lower capacities at high C-rates (> 0.5C). The proof-of-concept was therefore achieved, further improvement of the cell performance will be focused on in the future. Figure 1

Amylase production from marine sponge Hymeniacidon perlevis; potentials sustainability benefits.

The marine sponge Hymeniacidon perlevis is a globally distributed and invasive species with extensive filter-feeding characteristics. The symbiotic relationship fostered between the sea sponge and the inhabiting microorganism is key in the production of metabolic enzymes which is the focus of this study. Sponge bacterial symbionts were grown on starch agar for 48hrs. Colourimetric analyses of amylase were conducted at 540nm using a spectrophotometric plate reader. Using an X-Bridge column (3.5μM, 4.6x150mm), 80/20 acetonitrile/water in 0.1% ammonium were the conditions used for the liquid chromatography-mass spectrometry (LC-MS) analyses. Seven reducing sugars were used to optimise LC-MS to determine the presence of the crude enzyme formed. Not all the bacterial symbionts isolated from H perlevis produced alpha and beta amylases to break down starch. From the statistical mean of crude enzyme concentrations from the hydrolysis of starch by amylase, isolate seven had the highest optical density (OD) at 0.43475 while isolate twelve had the lowest OD at 0.141417. From the LC-MS analysis, out of the seven sugars, Glucose and maltose constituted > 65% of the reducing sugars formed from the hydrolysis of starch by the amylases. Isolates 3,6 and 7 produced 6.906 mg/l, 12.309 mg/l, and 5.909 mg/l of glucose, while isolates 3,4,5,6 and 7 produced 203.391 mg/l, 176.238 mg/l, 139.938 mg/l, 39.030 mg/l, and 18.809 mg/l of maltose, respectively. Isolate two had the highest amount of maltose at a concentration of 267.237 mg/l while isolate four had the highest amount of glucose concentration of 53.084 mg/l. Enzymes from marine sponge bacteria offer greater potential for a green and sustainable production process. Amylase extraction from bacterial symbionts in H perlevis is sustainable and should be supported. They can serve as reliable sources of revenue for enzyme industries, and applications in food industries and biotechnological processes.

Dispersed Bi2S3 site in a porphyrin-based metal–organic framework for photocatalytic nitrogen fixation

The development of suitable alternatives to the energy-intensive and seriously polluting Haber–Bosch process for ammonia production is crucial. Photocatalytic nitrogen fixation has attracted extensive research attention as a pollution-free, low-cost, and sustainable ammonia production process. However, most reported photocatalysts so far have relatively low conversion rates for N2 reduction. Herein, we employed a strategy based on bismuth precoordination and in-situ sulfurization strategy to grow highly dispersed bismuth sulfide (Bi2S3) on a porous coordination network (PCN) metal–organic framework. The as-fabricated photocatalyst (Bi2S3@PCN-2) with high-density heterojunctions was used for the photocatalytic nitrogen fixation for ammonia production and degradation of bisphenol A, achieving an ammonia production rate of 3880 μg h−1 g−1 and a 96.4% degradation efficiency for bisphenol A within 30 min in the absence of a sacrificial agent. The abundant porphyrin rings and highly dispersed Bi2S3 broadened the visible-light absorption range of the photocatalyst, leading to numerous photogenerated charge carriers. Additionally, the high-density heterojunctions facilitated the separation of photogenerated electron–hole pairs, resulting in excellent photocatalytic performance. This work provides a new approach for the design and preparation of bifunctional photocatalysts.