Large-scale Production Research Articles

Screening of novel β-carotene hydroxylases for the production of β-cryptoxanthin and zeaxanthin and the impact of enzyme localization and crowding on their production in Yarrowia lipolytica

Zeaxanthin, a vital dietary carotenoid, is naturally synthesized by plants, microalgae, and certain microorganisms. Large-scale zeaxanthin production can be achieved through plant extraction, chemical synthesis, or microbial fermentation. The environmental and health implications of the first two methods have made microbial fermentation an appealing alternative for natural zeaxanthin production despite the challenges in scaling up the bioprocess. An intermediate between β-carotene and zeaxanthin, β-cryptoxanthin, is found only in specific fruits and vegetables and has several important functions for human health. The low concentration of β-cryptoxanthin in these sources results in low extraction yields, making biotechnological production a promising alternative for achieving higher yields. Currently, there is no industrially relevant microbial fermentation process for β-cryptoxanthin production, primarily due to the lack of identified enzymes that specifically convert β-carotene to β-cryptoxanthin without further conversion to zeaxanthin. In this study, we used genetic engineering to leverage the oleaginous yeast Yarrowia lipolytica as a bio-factory for zeaxanthin and β-cryptoxanthin production. We screened 22 β-carotene hydroxylases and identified eight novel enzymes with β-carotene hydroxylating activity: six producing zeaxanthin and two producing only β-cryptoxanthin. By introducing the β-carotene hydroxylase from the bacterium Chondromyces crocatus (CcBCH), a β-cryptoxanthin titer of 24 ± 6 mg/L was achieved, representing the highest reported titer of sole β-cryptoxanthin in Y. lipolytica to date. By targeting zeaxanthin-producing β-carotene hydroxylase to the endoplasmic reticulum and peroxisomes, we increased the production of zeaxanthin by 54% and 66%, respectively, compared to untargeted enzyme. The highest zeaxanthin titer of 412 ± 34 mg/L was achieved by targeting β-carotene hydroxylases to peroxisomes. In addition, by constructing multienzyme scaffold-free complexes with short peptide tags RIDD and RIAD, we observed a 39% increase in the zeaxanthin titer and a 28% increase in the conversion rate compared to the strain expressing unmodified enzyme. The zeaxanthin titers obtained in this study are not the highest reported; however, our goal was to demonstrate that specific approaches can enhance both titer and conversion rate, rather than to achieve the maximum titer. These findings underscore the potential of Y. lipolytica as a promising platform for carotenoid production and provide a foundation for future research, where further optimization is required to maximize production.

Valorizing Waste Streams to Enhance Sustainability and Economics in Microbial Oil Production.

Driven by demand for more sustainable products, research and capital investment has been committed to developing microbially produced oils. While researchers have shown oleaginous yeasts and other microbes can produce low-carbon footprint oils by leveraging waste streams as energy sources, previous analyses have not fully explored the quantity of available waste streams and in turn economy-of-scale enabled on capital and operating expenses. This paper makes parallels to 2G ethanol facilities, enabling a data-driven understanding of large-scale production economics. Production costs are broken down for a variety of scenarios. The analysis finds that reaching price parity with large-scale commodity oils (e.g., palm oil, high-oleic cooking oils, biofuels feedstock oils, lauric acid) is not possible today and unlikely even under aggressive future assumptions about strain productivity. Instead, commercial production must be targeted at end markets where sustainability-conscious consumers are willing to pay the price premiums identified in this paper.

Effects of Temperature and Light on Microalgal Growth and Nutrient Removal in Turtle Aquaculture Wastewater

The aim of this study was to explore the effects of temperature and light on microalgal growth and nutrient removal in turtle aquaculture wastewater using a single-factor experiment method. Results showed that the growth process of Desmodesmus sp. CHX1 in turtle aquaculture wastewater exhibited three stages, namely adaptation, logarithmic, and stable periods. Temperature and light significantly influenced the growth and protein and lipid accumulation of Desmodesmus sp. CHX1. The optimal conditions for the growth and biomass accumulation of Desmodesmus sp. CHX1 included a temperature of 30 °C, a photoperiod of 24L:0D, and a light intensity of 180 μmol photon/(m2·s). Increased temperature, photoperiod, and light intensity enhanced nutrient removal efficiency. Maximum nitrogen removal was achieved at a temperature of 30 °C, a photoperiod of 24L:0D, and a light intensity of 180 μmol photon/(m2·s), with the removal efficiency of 86.53%, 97.94%, 99.57%, and 99.15% for ammonia, nitrate, nitrite, and total phosphorus (TP), respectively. Temperature did not significantly affect TP removal, but increased photoperiod and light intensity improved the removal efficiency of TP. The development of microalgae biomass as a feed rich in protein and lipids could address feed shortages and meet the nutritional needs of turtles, offering a feasible solution for large-scale production.

A yeast surface display platform for screening of non-enzymatic protein secretion in Kluyveromyces lactis.

Enhancing the secretion of recombinant proteins, particularly non-enzymatic proteins that predominate in food and pharmaceutic protein products, remains a significant challenge due to limitations in high-throughput screening methods. This study addresses this bottleneck by establishing a yeast surface display system in the food-grade microorganism Kluyveromyces lactis, enabling efficient display of model target proteins on the yeast cell surface. To assess its potential as a universal high-throughput screening tool for enhanced non-enzymatic protein secretion, we evaluated the consistency between protein display levels and secretion efficiency under the influence of various genetic factors. Our results revealed a strong correlation between these two properties. Furthermore, screening in a random mutagenesis library successfully identified a mutant with improved secretion. These findings demonstrate the potential of the K. lactis surface display system as a powerful and universal tool for high-throughput screening of strains with superior non-enzymatic protein secretion capacity. We believe this study could pave the way for efficient large-scale production of heterologous food and therapeutic proteins in industries. KEY POINTS: • A YSD (yeast surface display) system was established in Kluyveromyces lactis • This system enables high-throughput screening of non-enzymatic protein secretion • This technology assists industrial production of food and therapeutic proteins.

A Developed Approach for Synthesizing Novel Fe3O4/FeO/BaCl2 Composites with Broadband and High-Efficiency Microwave Absorption Performance.

Designing high-performance microwave absorbing materials that are thin and exhibit strong absorption capabilities across a wide frequency range is critical for mitigating electromagnetic pollution through a simple, highly adaptable, and cost-effective approach. However, achieving these three targets remains a significant challenge. In this research a simple approach suitable for large-scale production of microwave absorbing materials, namely, Fe3O4/FeO/BaCl2 composites, is proposed, which includes the processes of chemical coprecipitation and calcination. The above approach can adjust the mass ratio of Fe3O4/FeO while prompt the formation of BaCl2 with mesoporous structure on the surface of Fe3O4/FeO, meeting the need for desirable microwave absorbing performance. Subsequently, the impacts of varying mass ratios of the Fe3O4/FeO/BaCl2 composites on microstructures, magnetic properties, and microwave absorption properties were examined. Based on this investigation, a mass ratio close to 3.5:5.5:1 was determined to be optimal. At this ratio, the Fe3O4/FeO/BaCl2 composites realize an effective absorption bandwidth of 6.70 GHz at only 1.16 mm thickness, covering the whole Ku-band, and the maximum reflection loss can be close to -46.8 dB at 1.4 mm. The robust microwave absorption performance of Fe3O4/FeO/BaCl2 composites can be attributed to heterostructured multi-interface structural design, the comprehensive effects of multiple reflections and dielectric/magnetic losses induced by BaCl2 with mesoporous structure as well as the aggregated Fe3O4/FeO particles. This work may offer insights into designing and preparing effective microwave absorption materials.

Improvement and Characterisation of the ArCLight Large-Area Dielectric Light Detector for Liquid-Argon Time Projection Chambers

The detection of scintillation light in noble-liquid detectors is necessary for identifying neutrino interaction candidates from beam, astrophysical, or solar sources. Large monolithic detectors typically have highly efficient light sensors, like photomultipliers, mounted outside their electric field. This option is not available for modular detectors that wish to maximize their active volume. The ArgonCube light readout system detectors (ArCLights) are large-area thin-wavelength-shifting (WLS) panels that can operate in highly proximate modular detectors and within the electric field. The WLS plastic forming the bulk structure of the ArCLight has Tetraphenyl Butadiene (TPB) and sheets of dichroic mirror layered across its surface. It is coupled to a set of six silicon photomultipliers (SiPMs). This publication compares TPB coating techniques for large surface areas and describes quality control methods for large-scale production.

Advances in Bacterial Cellulose Production: A Scoping Review

The versatility, contribution to sustainability, and diversity of applications of bacterial cellulose require large-scale production processes and new alternatives in terms of biological systems that, under controlled conditions, favor the growth and production of this biomaterial. This review article describes the technologies developed and the advances achieved in regard to the production of bacterial cellulose on a small and large scale, according to the findings evidenced in the scientific literature in the last ten years. A review, based on the guidelines in the PRISMA® methodology, of a selection of articles was carried out, with a Cohen’s Kappa coefficient of 0.465; scientific databases, such as Web of Science, SCOPUS, PubMed, Taylor and Francis, and ProQuest, were considered. There is a wide variety of bacterial pulp production systems and the design of such a system is based on the type of cellulose-producing bacteria, oxygen requirements, mixing and agitation, temperature control, sterilization and cleaning requirements, and production scalability. The evolution in the development of bioreactors for bacterial cellulose has focused on improving the production process’s efficiency, productivity, and control, and adapting to the specific needs of bacterial strains and industrial applications.

Active cardboard box with palm wood waste powder and orange oil to prevent browning and quality loss in cabbage: Mode of action and potential for reuse.

Browning, caused by enzymatic activity and storage conditions, affects cabbage during cold storage and is crucial for customer acceptance. This study investigated the effect of cardboard packaging containing low concentrations of nano-orange oil (ONE) at 0.006% in palm wood waste powder for anti-browning and extending the shelf life of cabbage. The incorporation of ONE into palm wood powder (PWP) using different methods (soaking, vapor, vapor with ultrasonic device, and control) was examined before using the active PWP to develop cardboard cabbage packaging. The reuse of the active cabbage box packaging was also investigated for up to three reuses. The results showed that a greater anti-browning effect was achieved with cardboard packaging made from active PWP with orange oil vapor and an ultrasonic device compared to other adsorption methods, with significantly higher inhibition of the key browning enzyme activities of polyphenol oxidase (PPO) and peroxidase (POD). Additionally, antioxidant activity and bioactive compounds were improved, maintaining the bright green color of cabbage after 21 days of storage. The shelf life of cabbage stored in active cardboard was extended to at least 21 days compared to 5 days for the control. The active cabbage box with PWP and ONE vapor with an ultrasonic device showed potential for reuse at least two times. Limonene was found on the surface of stored cabbage and may be a key factor in antimicrobial activity, helping to control microbial growth on the cabbage surface within standard limits during long-term storage. This finding provides valuable guidance for reducing cabbage waste during transportation and storage from farm to market. PRACTICAL APPLICATION: This research offers new insights into active cardboard packaging made from palm wood powder with a low concentration of orange oil vapor to prevent browning and microbial growth in storage boxes. The optimal method for producing this packaging uses nano-orange oil vapor at 0.006% with an ultrasonic device, which could be feasible for large-scale production. The packaging effectively reduced PPO and POD enzyme activity, delaying browning and extending cabbage shelf life by at least threefold compared to the control, while maintaining color and freshness. This cost-effective method promotes the sustainable use of agricultural waste in the fresh vegetable industry, as it can be reused at least twice, benefiting farmers and reducing cabbage waste.

Hydrogenating Polyethylene Terephthalate into Degradable Polyesters.

The recycling and upcycling of polyethylene terephthalate (PET), the most widely used polyester plastic globally, has attracted growing attention concerning its disposal as non-degradable waste in the natural environment. Transforming end-of-life PET into (bio)degradable polyester offers a novel approach to managing its waste. In this study, we introduce a simple process capable of converting waste PET into degradable polyester, polyethylene terephthalate-polyethylene-1,4-cyclohexanedicarboxylate (PET-PECHD), by partly hydrogenating the aromatic rings (x) into aliphatic ones (y). The polyesters with variable x/y compositions ranging from 100/0 to 0/100 can be achieved, and the molecular weight (Mw) can be maintained when x/y > 87/13 due to the nonobvious depolymerization. Pronounced depolymerization would occur with deeper hydrogenation, which generates a blend of PET-PECHD and polyethylene-1,4-cyclohexanedicarboxylate (PECHD) with lower Mw, and finally a single-type polymer PECHD. The PET-PECHD demonstrates comparable thermal stability and mechanical strength compared to PET, along with superior extensibility, barrier properties, and (bio)degradability in acidic, alkaline solutions, and moist soil. This research highlights the potential for cost-effective, large-scale production of degradable polyester from real-life plastic waste.

The role of FexCu(1‒x) electrodeposits from a deep eutectic solvent in promoting the hydrogen evolution reaction

Hydrogen from water splitting is more powerful, clean, and more energy-efficient than fossil fuels. Since the electrode material influences the performance and operating cost of industrial electrolyzers, this work induces technological innovation through FexCu(1−x) alloys with electrocatalytic action toward the hydrogen evolution reaction (HER). The materials were galvanostatically deposited on 1020 carbon steel. It was used electrolytes formulated with deep eutectic solvents (DES) and aqueous solvents (AQS) were used to verify their influence on the coatings' composition, morphology, and electrocatalytic activity. The results proved that even after fixing the operating conditions (electrochemical potential, current density, and deposition time), the alloys produced in DES are richer in Fe (≅ 77-85%, w/w). For comparison, those obtained from AQS have greater proportion of Cu (≅ 65%, w/w). Stoichiometry changes also alter the topography, surface area, and electrocatalytic activity of FexCu(1−x) alloys for hydrogen production. The electrochemical studies carried out also revealed that the association between Fe and Cu as alloying elements has a positive synergistic effect of reducing the HER overpotential by around 125 mV, using 1 mol L−1 KOH at 296 K. Considering stability and resistance to corrosion, FexCu(1−x) alloys produced in DES stood out as the most promising for possible adaptation in electrolyzers developed for large-scale hydrogen production.

Optimizing Fermentation Strategies for Enhanced Tryptophan Production in Escherichia coli: Integrating Genetic and Environmental Controls for Industrial Applications

Tryptophan is an essential aromatic amino acid widely used in the pharmaceutical, agricultural, and feed industries. Microbial fermentation, mainly using Escherichia coli, has become the preferred method for its production due to sustainability and lower costs. Optimizing tryptophan production requires careful control of various fermentation parameters, including nutrients, pH, temperature, and dissolved oxygen (DO) levels. Glucose, as the primary carbon source, must be fed at controlled rates to avoid metabolic overflow, which leads to by-product accumulation and reduced production efficiency. Nitrogen sources, both organic (such as yeast extract) and inorganic (like ammonium), influence biomass growth and tryptophan yield, with ammonium levels requiring careful regulation to avoid toxic accumulation. Phosphate enhances growth but can lead to by-product formation if used excessively. pH is another critical factor, with an optimal range between 6.5 and 7.2, where enzyme activity is maximized. Temperature control promotes growth and production, particularly between 30 °C and 37 °C. High DO levels increase tryptophan titers by boosting the pentose phosphate pathway and reducing by-products like acetate. Furthermore, surfactants and supplements such as betaine monohydrate and citrate help alleviate osmotic stress and enhance precursor availability, improving production efficiency. Careful manipulation of these parameters allows for high-density cell cultures and significant tryptophan accumulation, making microbial fermentation competitive for large-scale production.

A novel multi-information fusion CNN for defect detection in laser soldering of SAC305

Identification of laser soldering of lead-free solder Sn-3.0Ag-0.5Cu (SAC305) in electronic packaging was still an enormous challenge. It was difficult to detect defects in large-scale production. This work proposed an identification model based on multi-information fusion convolutional neural network (MIFCNN) for inspecting laser soldering process. In this method, the forty images in chronological order and the temperature data were combined as the input to be utilized in detecting defects. The results demonstrated that MIFCNN had best accuracy for three types of joints with accuracy of 98.28 % due to the combination of images and temperature information. The ICNN and TCNN had poor recognition accuracy for the warpage defect with 73.9 % and the poor wetting defect with 66.5 %, respectively. This was because the images and temperature information were the key to identifying the poor wetting defects and warpage defects, respectively. The poor wetting defect could be recognized by difference of contact angle, while the warpage defect could be significantly detected by maximum temperature. This work could help detecting defects of laser soldering in the actual production and widen the application of MIFCNN in the field of laser soldering.

Metabolic engineering of Streptomyces roseosporus for increased production of clinically important antibiotic daptomycin.

Daptomycin (DAP), a novel cyclic lipopeptide antibiotic produced by Streptomyces roseosporus, is clinically important for treatment of infections caused by multidrug-resistant Gram-positive pathogens, but the low yield hampers its large-scale industrial production. Here, we describe a combination metabolic engineering strategy for constructing a DAP high-yielding strain. Initially, we enhanced aspartate (Asp) precursor supply in S. roseosporus wild-type (WT) strain by separately inhibiting Asp degradation and competitive pathway genes using CRISPRi and overexpressing Asp synthetic pathway genes using strong promoter kasOp*. The resulting strains all showed increased DAP titre. Combined inhibition of acsA4, pta, pyrB, and pyrC increased DAP titre to 167.4 μg/mL (73.5% higher than WT value). Co-overexpression of aspC, gdhA, ppc, and ecaA led to DAP titre 168 μg/mL (75.7% higher than WT value). Concurrently, we constructed a chassis strain favourable for DAP production by abolishing by-product production (i.e., deleting a 21.1 kb region of the red pigment biosynthetic gene cluster (BGC)) and engineering the DAP BGC (i.e., replacing its native dptEp with kasOp*). Titre for the resulting chassis strain reached 185.8 μg/mL. Application of our Asp precursor supply strategies to the chassis strain further increased DAP titre to 302 μg/mL (2.1-fold higher than WT value). Subsequently, we cloned the engineered DAP BGC and duplicated it in the chassis strain, leading to DAP titre 274.6 μg/mL. The above strategies, in combination, resulted in maximal DAP titre 350.7 μg/mL (2.6-fold higher than WT value), representing the highest reported DAP titre in shake-flask fermentation. These findings provide an efficient combination strategy for increasing DAP production and can also be readily applied in the overproduction of other Asp-related antibiotics.

Kinetics of hydrothermal reactions of n-butanol over Pt/Al2O3 catalyst for biopropane fuel gas production

Energy defossilisation using drop-in biofuels is an important step towards Net Zero. Producing low-carbon clean-burning propane fuel from biomass provides such additional sustainability benefits. In this work, kinetics of hydrothermal reactions of n-butanol, a biomass-derived feedstock, to produce propane over 5 wt% Pt/Al2O3 catalyst have been studied from 523- 573 K. Experimental data revealed negligible internal and external mass transfer effects and, when fitted to an integral power-rate law equation, gave activation energy of 70 kJ mol−1 (n-butanol reaction order = 1). Furthermore, an appropriate Langmuir-Hinshelwood model was developed, which predicted similar activation energy 62 kJ mol−1. Low adsorption enthalpies for n-butanol (–33.51 kJ mol−1) and water (−18.16 kJ mol−1) indicated weak interactions on the catalyst surface. These agreed with the fast reaction rate of ≈1.0 x 10-5 mol gcat-1 s−1 obtained at ≥ 548 K. As a new research area, generation of such accurate kinetics data will contribute to process development for large-scale biopropane production.

Developing PVDF hollow fiber membrane enhanced by braided tube and modified by bionic coating for treating aldehyde-containing wastewater

This study originates from the difficulties encountered in the wastewater treatment from a large-scale methionine production line. Despite the superior performance of the polytetrafluoroethylene (PTFE) membrane, significant issues still persist. The PTFE layer tend to peer off leading to substandard effluent quality, and membrane fouling rate is relatively rapid. To overcome the peeling issue, braided tubes were used to enhance the mechanical strength. To improve the interface bonding between the PVDF layer and braided tubes, two modifiers are introduced to modify the surfaces of braided tubes. Then, the embedded braided tube enhanced PVDF membrane is prepared. On this basis, the one-step bionic coating PVDF (OSBC-PVDF) membrane was prepared by utilizing the polydopamine coating, polyethylene glycol and Cu nanoparticles. It was found that the embedded structure resembling “teeth and gums” formed, significantly improving the mechanical properties to prevent the peeling off of the separation layer. The optimal reaction temperature, reaction time and modifier dosage for preparing the OSBC-PVDF membrane are separately 25 °C, 2 h and 20 g. More importantly, the OSBC-PVDF membrane has withstood the test of 300 days of continuous operation. The stable water quality of the effluent demonstrated that the above issues had been overcome.

Evaluation of large-scale poultry manure-derived biochar for efficient cadmium removal in zinc smelter wastewater

Cadmium (Cd), a carcinogen, is released from industrial activities like metal refineries and battery runoff, with significant contamination reported near zinc smelters in Korea. This study addresses the issue using an efficient, economical adsorption process with waste-derived biochar-based adsorbents known for high Cd removal. Poultry manure (PM), typically used as fertilizer, can lead to environmental pollution if mismanaged; therefore, it was pyrolyzed to produce biochar. The resulting poultry manure biochar (PMBC) was produced on a large scale (15 ton/day), demonstrating feasibility for large-scale implementation. The effectiveness of PMBC as an adsorbent for Cd was evaluated using wastewater discharged from a zinc smelter. The Cd adsorption capacity of PMBC (60.39 mg/g) was lower than that (302.0 mg/g) of hen manure biochar produced at a laboratory scale in our previous study but was comparable to other biochars reported in the literature. Response surface methodology analysis indicated that reaction time, dose, and agitation significantly influenced Cd removal by PMBC, whereas pH had a negligible impact. Notable contributions to Cd adsorption include the release of K+ from PMBC and the presence of O-containing functional groups. Under continuous flow conditions with real wastewater, Cd was not detected in the effluent for the initial 8 h, and PMBC sustained a removal efficiency of 40.77% until saturation was reached. The results from wastewater treatment and large-scale biochar production offer valuable insights into the potential of biochar as a medium for addressing environmental issues in real-world applications.

Cr-doped NiFe sulfides nanoplate array: Highly efficient and robust bifunctional electrocatalyst for the overall water splitting and seawater electrolysis

To replace precious metals and reduce production costs for large-scale hydrogen production, developing stable, high-performance transition metal electrocatalysts that can be used in a wide range of environments is desirable yet challenging. Herein, a self-supported hybrid catalyst (NiFeCrSx/NF) with high electrocatalytic activity was designed and constructed using conductive nickel foam as a substrate via manipulation of the cation doping ratio of transition metal compounds. Due to the strong coupling synergy between the metal sulfides NiS2, Fe9S11, and Cr2S3, as well as their interaction with the conductive nickel foam (NF), the energy barrier for catalytic reactions is reduced, and the charge transfer rate is enhanced. This significantly improves the hydrogen evolution reaction (HER) performance of NiFeCrSx/NF, achieving a current density of 10 mA cm−2 with an overpotential of just 66 mV. Furthermore, doping with chromium generates different valence states of Cr during the catalytic process, which can synergize with the high-valent Fe and Ni, promoting the formation of oxygen vacancies and enriching the active sites for the oxygen evolution reaction (OER). Consequently, at a current density of 10 mA cm−2 in 1.0 M KOH, the overpotential for OER is only 223 mV for NiFeCrSx/NF. Additionally, the in situ grown of self-supporting nanoflower structure on NiFe-LDH not only provides a large catalytic surface area but also facilitates electrolyte penetration during the catalytic process, endowing NiFeCrSx/NF with high long-term stability. When used as a bifunctional catalyst for overall water splitting, the NiFeCrSx/NF||NiFeCrSx/NF electrolyzer requires only 1.29 V to deliver a current density of 10 mA cm−2. Simultaneously, Cr doping protects the Fe sites by maintaining stable valence states, ensuring high performance and stability of NiFeCrSx/NF, even when it is utilized for seawater splitting. This strategy offers novel concepts for creating catalysts based on non-precious metals that can be utilized in various application scenarios.

Physicochemical properties of lard oil and rubber seed oil blends and their comprehensive characterization

This research investigates the potential of blending complementary lard oil with rubber seed oil as feedstock for biodiesel production. Rubber seed oil, obtained through hexane extraction using the Soxhlet method, contains the major fatty acids of oleic acid (C18:1), palmitic acid (C16:0), linoleic acid (C18:2), and stearic acid (C18:0), while rubber seed oil primarily consists of linoleic acid (C18:2), oleic acid (C18:1), linolenic acid (C18:3), palmitic acid (C16:0), and stearic acid (C18:0). Th least acid value of lard oil (0.55 mg KOH/g) can benefit of reducing soap formation of rubber seed oil during transesterification process in biodiesel production due to its substantial-high acid value (16.28 mg KOH·g–1). Blending at ratios below 80:20 v/v produced biodiesel exceeding 85%, utilizing CaO as a catalyst. Lard oil demonstrated a higher reaction rate constant (11.88×10–3 min–1) than rubber seed oil (2.11×10–3 min–1), indicating a significant difference in performance. High acid value and free fatty acids in rubber seed oil correlated with lower reaction rates. Maintaining a mixture ratio below 80:20 v/v optimized reaction rates during biodiesel production. Biodiesel obtained from blends below 80:20 v/v met ASTM D6751 and EN 14214 standards, demonstrating suitability for bio-auto fuel. The drawbacks of using rubber seed oil as a raw material for biodiesel production are overcome by blending with lard oil, giving rise to expanding renewable energy options for rural communities, community enterprises, and large-scale biodiesel production.

Probing an LSTM-PPO-Based reinforcement learning algorithm to solve dynamic job shop scheduling problem

With the growth of personalized demand and the continuous improvement in social productivity, the large-scale and few-variety centralized production model is gradually transitioning towards a personalized model of small batches and multiple varieties, which makes the manufacturing process of the job shop increasingly complex. Furthermore, disruptive events such as machinery failures and rush orders in the job shop increase the uncertainty and variability of the production environment. Traditional scheduling methods are usually based on fixed rules and heuristic algorithms, which are difficult to adapt to constantly changing production environments and demands. This may lead to inaccurate scheduling decisions and hinder the optimal allocation of job shop resources. To solve the dynamic job shop scheduling problem (JSP) more effectively, this paper proposes a Reinforcement Learning (RL) optimization algorithm integrating long short-term memory (LSTM) neural network and proximal policy optimization (PPO). It can dynamically adjust scheduling strategies according to the changing production environment, achieving comprehensive status awareness of the job shop environment to make optimal scheduling decisions. First, a state-aware network framework based on LSTM-PPO is proposed to achieve real-time perception of job shop state changes. Then, the state and action space of the job shop are described within the context of the state-aware network framework. Finally, an experimental environment is established to verify the algorithm’s effectiveness. Training the LSTM-PPO algorithm makes it feasible to achieve better performance than other scheduling methods. By comparing the initial planning time with the actual completion time of the rescheduling decision under different dynamic disturbances, the efficiency of the proposed algorithm is verified for the dynamic JSP

High efficient synthesis of benzyl lactate through waste PLA alcoholysis by protic ionic salt

Benzyl lactate (BL) is a critical reagent in pharmaceutical and chemical synthesis due to its versatility. Traditional synthesis of BL was constrained by the high cost and low yield, thereby hindering the feasibility of large-scale production. Here, we reported a novel synthesis strategy for BL by utilizing the alcoholysis of waste polylactic acid (PLA) by benzyl alcohol with the protic ionic salt, HTBD-OAc, as the catalyst. The gram-scale experiments achieved a 94.9 % yield, and the robustness of this reaction was evidenced by the yield maintaining 92.5 % across six recycling experiments. More impressively, kilogram-scale synthesis facilitated a complete conversion of PLA to BL, achieving an unprecedented yield of 98.7 % at 180 °C within two hours. The exceptional catalytic efficiency of this reaction is attributed to the synergistic functions between the HTBD+ cation and OAc− anion in the catalyst HTBD-OAc. This study heralds a significant stride towards the sustainable and scalable production of high-purity benzyl lactate, paving the way for extended industrial applicability for this essential compound.