Product Yield Research Articles

A parallel bioreactor strategy to rapidly determine growth-coupling relationships for bioproduction: a mevalonate case study

BackgroundThe climate crisis and depleting fossil fuel reserves have led to a drive for ‘green’ alternatives to the way we manufacture chemicals, and the formation of a bioeconomy that reduces our reliance on petrochemical-based feedstocks. Advances in Synthetic biology have provided the opportunity to engineer micro-organisms to produce compounds from renewable feedstocks, which could play a role in replacing traditional, petrochemical based, manufacturing routes. However, there are few examples of bio-manufactured products achieving commercialisation. This may be partially due to a disparity between academic and industrial focus, and a greater emphasis needs to be placed on economic feasibility at an earlier stage. Terpenoids are a class of compounds with diverse use across fuel, materials and pharmaceutical industries and can be manufactured biologically from the key intermediate mevalonate.ResultsHere, we report on a method of utilising parallel bioreactors to rapidly map the growth-coupling relationship between the specific product formation rate, specific substrate utilisation rate and specific growth rate. Using mevalonate as an example product, a maximum product yield coefficient of 0.18 gp/gs was achieved at a growth rate (μ) of 0.34 h−1. However, this process also led to the formation of the toxic byproduct acetate, which can slow growth and cause problems during downstream processing. By using gene editing to knock out the ackA-pta operon and poxB from E. coli BW25113, we were able to achieve the same optimum production rate, without the formation of acetate.ConclusionsWe demonstrated the power of using parallel bioreactors to assess productivity and the growth-coupling relationship between growth rate and product yield coefficient of mevalonate production. Using genetic engineering, our resultant strain demonstrated rapid mevalonate formation without the unwanted byproduct acetate. Mevalonate production is quantified and reported in industrially relevant units, including key parameters like conversion efficiency that are often omitted in early-stage publications reporting only titre in g/L.

An azide-based sampler for monitoring abiotic reduction of chlorinated solvent contaminants in groundwater.

There is significant interest in monitoring abiotic decomposition of chlorinated solvents at contaminated sites due to large uncertainties regarding the rates of abiotic attenuation of trichloroethylene (TCE) and perchloroethylene (PCE) under field conditions. In this study, an innovative passive sampling tool was developed to quantify acetylene, a characteristic product of abiotic reduction of TCE or PCE, in groundwater. The sampling mechanism is based on the highly specific and facile click reaction between acetylene and an azide compound to form a biologically and chemically stable triazole product. In preliminary investigations using static solutions of acetylene, a strong linear relationship was observed between the quantity of azide formed and the concentration of aqueous acetylene. The product yield was stable within a solution pH range of 5-9 and in the presence of common groundwater salts or gaseous hydrocarbon molecules. Based on these results, a prototypical acetylene passive sampler was constructed, which featured a piece of PDMS membrane embedded with an azide compound and Cu(0) catalyst to form a reactive phase for acetylene capture. The sampler was evaluated in microcosm reactors containing TCE and an abiotic reductant (viz., sulfur-treated iron powder). Acetylene produced during abiotic dechlorination of TCE was effectively captured by the sampler, and the quantity of the product recovered from the sampler correlates with the amount of TCE converted. The specificity and sensitivity of the proposed acetylene sampler proffers a new diagnostic tool for monitoring abiotic degradation of chlorinated ethenes at complex contamination sites.

High-level biosynthesis and purification of the antimicrobial peptide Kiadin based on non-chromatographic purification and acid cleavage methods

Antimicrobial peptides (AMPs) are renowned for their potent bacteriostatic activity and safety, rendering them invaluable in animal husbandry, food safety, and medicine. Despite their potential, the physiological toxicity of AMPs to host cells significantly hampers their biosynthetic production. This study presents a novel approach for the biosynthesis of the antimicrobial peptide Kiadin by engineering a DAMP4–DPS–Kiadin fusion protein to mitigate host cell toxicity and achieve high-level expression. Leveraging the unique properties of the DAMP4 protein, we developed a non-chromatographic purification method to isolate the DAMP4–DPS–Kiadin fusion protein with high purity. The instability of the D–P peptide bond under acidic conditions, combined with the thermal and saline stability of DAMP4, enabled efficient separation of Kiadin through acid cleavage and isoelectric precipitation, yielding Kiadin with 96% purity and a production yield of 29.3 mg/L. Our optimization of acid cleavage temperature, duration, and isoelectric precipitation conditions proved critical for maximizing the purification efficiency and expression levels of Kiadin. The biosynthesized Kiadin exhibited robust bacteriostatic activity against Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Bacillus cereus and Staphylococcus aureus. Notably, Kiadin demonstrated significant post-antibiotic effects by disrupting bacterial membrane integrity, inducing cytoplasmic leakage, and inhibiting biofilm formation in E. coli K88 and S. aureus Mu50, without cytotoxicity towards mouse macrophages. In vivo studies further confirmed Kiadin's exceptional therapeutic efficacy against abdominal infections caused by E. coli K88. The acid cleavage and non-chromatographic purification techniques developed in this study offer a cost-effective and efficient strategy for the high-purity production of AMPs.

Intermittent Optimization of Shale Gas Wells Based on Reservoir–Wellbore Coupling

Shale gas, as an important component of unconventional energy, holds enormous potential value in the energy sector. However, due to the complex geological characteristics and fluid flow mechanisms of shale gas reservoirs, its exploitation faces numerous challenges. This study focuses on the optimization of intermittent production methods for shale gas wells in the Changning block. In this study, a dynamic coordination model of formation recharge and wellhead output was established using real-time pressure monitoring and historical production records as key inputs. Based on this, the dimensionless production efficiency index was optimized by finely regulating the switching timing of the wellhead, thus significantly enhancing the cumulative oil production of the well. The conclusions indicate that the optimization methods proposed in this study can effectively guide the production operations of shale gas wells in the Changning block, thereby enhancing production yield and stability. This research contributes practical value to the field by offering theoretical support and practical guidance for shale gas exploitation, addressing technical challenges in the process.

Photochemical versus thermal thiol‐ene “click chemistry” for renewable polyols with application in polyurethanes

AbstractThe primary goal of the study was to compare the efficacy of two approaches, photochemical and thermal, in producing polyols from renewable soybean oil through thiol‐ene reactions. The thiol‐ene reaction was initiated with UV light in the presence of 2‐hydroxy‐2‐methylpropiophenone as a photo‐initiator or via a thermal pathway utilizing radical initiator 2,2′‐Azobis(2‐methylpropionitrile). The resulting polyols were analyzed using standard analytical techniques including Fourier transform infrared (FT‐IR) and nuclear magnetic resonance (NMR) spectroscopies. It was observed that the polyols obtained through the photochemical route exhibited better outcome compared with those synthesized using the thermal treatment. Additionally, we employed computational chemistry technique using density functional theory (DFT) calculation to get insights into various product yields. The DFT results revealed that the hydrogen bond network likely contributed to the improved stability, hence obtained higher product yield of the polyol MSBO‐TMPAE compared with that of MSBO‐GAE. Our study also focuses on applying the synthesized polyols in polyurethane rigid foams and casts. The polyurethanes prepared from these polyols have comparable thermal and mechanical properties to that of the commercially available polyurethanes.

Aquaponics Advancements: A Comprehensive Exploration of Sustainable Aqua-Agriculture Practices in the Indian Context

Aquaponics, an innovative and symbiotic approach to agricultural practices, has gained increasing attention as a potential pathway to enhance the sustainability of ‘Aqua-Agri’ farming in India. This review comprehensively explores the current state of aquaponics in the Indian context, examining its overview, suitability, challenges, and potentiality. The analysis encompasses the ecological dynamics of aquaponic systems, emphasizing the efficient utilization of resources in Indian context, minimal environmental impact, and the potential for increased yields in both fish and plant production. Additionally, it explores successful case studies, showcasing the viability and adaptability of aquaponics across diverse regions in India. The review concludes by outlining future research directions and policy recommendations to foster the widespread adoption of aquaponics as a transformative and sustainable method within the aquaculture sector in India.

Climate Smart Agriculture in Food Insecurity Mitigation in Nigeria: A Conceptual Evaluation

Climate-Smart agriculture and its impact on food security have been topical issues in policy and food security discusses by successive governments in Nigeria however, the extent of its awareness among the farmers as a food insecurity mitigation measure has not been adequately represented in contemporary local literature hence the need for this research to ascertain the extent of awareness through: an examination of literary works by scholars in the field, assessing the extent of climate-smart procedures in agriculture and suggest where possible ideas to enhance its adoption. The study therefore evaluated secondary data and studies on the impacts of climate change on agriculture and how it can be mitigated through the adoption of climate smart approaches. Climate-Smart Agriculture is an emerging agricultural strategy initiated to tackle the consequences of climate change in food security and sustain agriculture. It involves the combination of approaches in the management of agricultural lands, forests, fisheries and livestock. The study in this regard took a holistic view of the adoption of climate smart agriculture by the farmers, its benefits and approaches and considered objectives such as accessing and assessing other scholars works and views on climate smart agricultural practices utilized by rural farmers in parts of Nigeria, discussing climate smart agriculture and food security, deliberating on climate smart agriculture and resource use efficiency and, viewing the constraining factors hampering the adoption of Climate Smart Agricultural practices in Nigeria. This is because climate change presently is one of the challenges and problems facing the world and an important factor in agricultural productivity. Variations in climatic factors will have ripple effects on crop yield and animal production. Farmers may have been facing weather variability and uncertainty patterns, however, the increasing pace of these uncertainties caused by climate change exacerbate food insecurity and hunger incidences and will require some degree of flexibility and rapid response capacity that climate smart agriculture offers. Building resilience in agricultural and farming practices will reduce the risk of food insecurity outside increasing the adaptive capacity and coping capabilities of the farmers.

Effect of Exogenous Inoculation on Dark Fermentation of Food Waste Priorly Stored in Lactic Acid Fermentation

Lactic acid fermentation has recently been shown to be a robust storage strategy for food waste prior to conversion to biohydrogen through dark fermentation. However, the importance of initial microbial communities and, more particularly, exogenous microorganisms on the conversion of lactic acid-rich stored substrate is not yet fully elucidated. This study investigates the impact of introducing exogenous inoculum to lactic acid-rich stored food waste prior to biohydrogen production in dark fermentation. Results showed exogenous inoculation produced a statistically significant increase in biohydrogen production rate (Rm) by 199%, 250%, 137%, 130%, 19%, and 10% compared to non-inoculated stored food waste after food waste storage at 4 °C, 10 °C, 23 °C, 35 °C, 45 °C, and 55 °C, respectively. Interestingly, no impact on the maximum production yield (Pm) was observed, but exogenous inoculation increased the accumulation of acetate, up to 160% more compared to endogenous inoculum. The main hydrogen-producing bacteria (HPB) were affiliated with Clostridium sp., while Prevotella_9 sp., another known HPB, was found after the fermentation of the food waste stored at 23 °C. In this study, the interest of exogenous inoculation to convert food waste stored by lactic acid fermentation was demonstrated through an increase in production rate along with higher accumulation of co-products, e.g., acetate. Such findings are promising for further development of process coupling, combining storage and conversion by fermentation of complex food waste.

Improving Photocatalytic Hydrogen Production over Pd Nanoparticles Decorated with g-C3N5 Photocatalyst

A uniform distribution of Pd nanoparticles on g-C3N5 layers is achieved through wet-chemical reduction (Pd/g-C3N5-EG). Pd/g-C3N5-EG demonstrates superior hydrogen production yield compared to heterojunctions synthesized via photoreduction (Pd/g-C3N5-PR), attributed to improved metal–support interaction. Pd/g-C3N5-EG demonstrates an average hydrogen evolution rate of 891.304 µmol g−1 h−1, representing a 7.8-fold increase over Pd/g-C3N5-PR and a 34.5-fold increase over bare g-C3N5. Pd/g-C3N5-EG also maintains its hydrogen production capability after five recycling cycles, with only a slight decrease in efficiency.

Molecular dynamics study on the effect of pressure on the combustion of NEPE propellant

The impact of pressure on the combustion micro-processes of NEPE propellant was studied through employing molecular dynamics simulation. A rational core–shell nanoparticle model (Al/Al2O3/NEPE) was established and simulated, we found the system temperature increased with rising pressure. Furthermore, the heightened pressure results in an advanced generation and increased yield of final products such as N2 and H2O, alongside an accelerated production and disappearance of intermediate molecules. For instance, with the pressure rising from 3 to 16 MPa, the yield of the final products increases from 30 to 75. Through in-depth analysis, the rapid increase in reaction rate can be attributed to the promotion of key exothermic reactions by elevated pressure. Specifically, the reactions (NO + NH2 = N2 + H2O and OH + HNO = H2O + NO) release a total heat of approximately 850 KJ/mol at 3000 K, leading to an increase in system temperature. This study holds significant promise in informing the regulation of combustion performance of NEPE propellant.

Mg(SPh)2 as a Catalyst for Efficient Photocatalytic Alkylation Reactions of Active Methylene Compounds with Nonactivated Alkenes

Mg(SPh)2 has been found to be a highly active catalyst in photocatalytic alkylation reactions of active methylene compounds with nonactivated alkenes. The desired reactions proceeded smoothly to afford the corresponding alkylated products in high yields with low catalyst loadings (0.2‐0.3 mol%). This protocol is applicable to a continuous‐flow system. Notably, magnesium is an earth‐abundant metal, and Mg(SPh)2 exhibits higher catalytic activity than the previously reported LiSPh.

Landscape Transformations (1987–2022): Analyzing Spatial Changes Driven by Mining Activities in Ayapel, Colombia

Gold mining is an activity that has developed in Colombia due to the great availability of mineral resources geographically distributed throughout the territory. The extraction techniques used are linked to the domain of illegality and to armed actors who have generated notable landscape impacts. This study, focused on the Municipality of Ayapel, Colombia, identifies the landscape units and analyzes the changes in land use and cover resulting from gold mining between the years 1987, 2002, and 2022, applying the CORINE Land Cover methodology, an adapted legend for Colombia, using Landsat satellite images. For this, the recognition of the physical geographical characteristics of the area was carried out in order to group homogeneous landscape units through a cartographic overlay of various layers of information, considering variables such as topography, geomorphology, and lithology. This research identifies a total of 16 landscape units, 8 of which were intervened in 1987, mainly associated with denudational hills. However, in 2022, 13 landscape units were intervened, with a considerable increase in the affected area. Particularly noteworthy is the occupation of landscape units associated with alluvial valleys, with an average of more than 30% of their total area. This demonstrates that they are the most attractive and vulnerable areas for mining exploitation, as they are the zones with the greatest potential for hosting mineral deposits. This impact has worsened over the last decade due to the introduction of other extraction techniques with machinery (dredges, dragon boats, backhoes, and bulldozers) that generate higher productive and economic yields but, at the same time, cause deep environmental liabilities due to the lack of administrative controls. The changes in extraction techniques, the increase in the international price of the commodity, and the absence of government attention have been the breeding ground that has driven gold mining activity.

IoT-based prediction model for aquaponic fish pond water quality using multiscale feature fusion with convolutional autoencoder and GRU networks

The Internet of Things (IoT)-based smart solutions have been developed to predict water quality and they are becoming an increasingly important means of providing efficient solutions through communication technologies. IoT systems are used for enabling connection between various devices based on the ability to gather and collect information. Furthermore, IoT systems are designed to address the environment and the automation industry. The threats associated with aquaponics farming are managed through an IoT-based smart water monitoring framework, which has become increasingly relevant in recent days. Therefore, this approach is crucial for achieving a remarkable improvement in order to increase the productivity rate and yield. The quality of water directly affects the rate of growth, efficiency of feed, and the overall health rate of the fish, plants, and bacteria. Insufficient knowledge about species selection poses a significant challenge in aquaponics farming, as it heavily relies on the water quality parameters. To address the challenges of conventional models, we have developed an effective IoT-based water quality prediction model, more specifically designed for aquaponic fish ponds. The data needed to perform the developed water quality prediction model will be acquired from “a simple dataset of aquaponic fish pond IoT” database. After that, these data are forwarded to the feature extraction phase. The weighted features, DBN (Deep Belief Network) features, and the original features are achieved in the feature extraction stage. The weighted features are obtained using the Revamped Fitness-based Mother Optimization Algorithm (RF-MOA). Subsequently, these extracted features are fed into the Multi-Scale feature fusion-based Convolutional Autoencoder with a Gated Recurrent Unit (MS-CAGRU) network for predicting the water quality. Thus, the water quality predicted data is obtained. The proposed model integrates GRU networks with a convolutional autoencoder to improve water quality prediction by capturing trends and managing temporal dependencies. It enhances accuracy by analysing key parameters and employing techniques to reduce overfitting. The effectiveness of the proposed system is evaluated in comparison to the traditional models using some evaluation measures.

Development of Lentiviral Packaging Cells and Scale Up of Production to Meet the Growing Demand in Cell and Gene Therapy.

Gamma-Retroviral (RVVs) and lentiviral vectors (LVVs) represent indispensable tools in somatic gene therapy, mediating the efficient, stable transfer of therapeutic genes into a variety of human target cells. LVVs, in contrast to RVVs, are capable of stably genetically modifying non-proliferating target cells, making them the superior instrument in cell and gene therapy. To date, the LVV manufacturing process employs human embryonic kidney cells (HEK293) and derivatives thereof transiently transfected with multiple plasmids encoding the required viral vector components. Alternatively, stable packaging cell lines were developed and engineered to express all vector components in trans. Currently, these cells are mostly cultured in cell stacks, where they grow adherently in 2D layers, limiting the scale-up of vector production. The production of viral vectors using stable suspension cell lines enables larger-scale production and higher yields under controlled conditions. Here, we review the improvements made to enhance vector safety and production yield. Current advancements in the establishment of stable packaging cell lines enabling inducible and constitutive LVV production are summarized and discussed. Manufacturing processes for lentiviral vectors using bioreactors with perfusion systems are required to meet the growing demand in cell and gene therapy and to reduce production and therapy costs.

Enhancing the acidic oxygen evolution reaction efficiency of sol–gel synthesized SrCo0.5Ir0.5O3 catalysts through optimized ball milling and acid leaching

High-efficiency and low-cost catalysts for the oxygen evolution reaction (OER) in acidic electrolytes are critical for electrochemical water splitting in proton exchange membrane (PEM) electrolyzers to produce green hydrogen, a clean fuel for sustainable energy conversion and storage. Among OER catalysts, solid-state synthesized SrCo1−xIrxO3 has demonstrated superior activity compared to commercial standards, such as IrO2 and RuO2. However, the solid-state synthesis process is economically inefficient for industrial use due to the potential for impurities and low yield of the final product. In addition, the requirement for electrochemical cycling to activate the catalyst introduces contaminations and uncertainties for industrial applications. In this study, a modified solution-based sol–gel method was employed to produce SrCo0.5Ir0.5O3 (SCIO) with high purity and yield. Subsequent ball milling and acid leaching treatments were applied, resulting in a catalyst with higher efficiency than those activated solely by electrochemical cycling. The electrochemical analysis and physical characterizations of our SCIO catalyst after ex-situ post-synthesis treatments show a similar active phase in composition and structure to those obtained through in situ electrochemical cycling and activation. Our approach simplifies the preparation process, making the catalyst ready for direct use in PEM electrolyzers without further treatment, offering a promising solution for producing high-performance, industrial-scale OER catalysts.

A Novel Enantioselective Synthesis of Cryptophycins Unit A from Rocher’s Ester

A novel synthesis of cryptophycin unit A in its enantiomerically pure form was achieved. In five steps, an enantiomeric mixture of unit A was initially prepared from trans-cinnamaldehyde. Subsequently, in its enantiomerically pure forms, unit A was prepared from Rocher’s ester in six steps, involving an essential aldehyde (2R,3E)-2-methyl-4-phenylbut-3-enal. The final step of this process involved two different approaches: a Reformatsky reaction of an essential aldehyde with tertbutyl 4-bromocrotonate and the vinylogous Mukaiyama aldol reaction with O,O-Silyl ketene acetal in the presence of isopropyl alcohol and L-tryptophane-based B-phenyloxazaborolidinone, thereby resulting in the desired products in good overall yields and high enantioselectivities.

Exploring the Linkages Between Land Degradation and Food Insecurity

Currently, two major challenges significantly threaten human civilisation: the degradation of land quality and the insufficient access to sustainable food supplies. They are becoming common in numerous places globally, especially in developing nations with elevated population growth rates. Prior studies have examined the impact of several types of land degradation, including soil erosion, waterlogging, stalinisation and desertification, on crop yield, water quality and agricultural productivity. This article comprehensively examines the interrelationship and reciprocal influence between land degradation and food insecurity, emphasising the intricate dynamics of elements contributing to both global challenges. The article analyses several types of land degradation, their direct and indirect effects on the foundations of food security, and how rising food demands exacerbate land degradation. The research advocates for collaborative initiatives at local, national, and global tiers to disrupt the detrimental cycle and establish a resilient, food-secure future.

Unraveling Crystal Phase-Driven Activity and Selectivity of WO3 for Photoelectrochemical Biomass Valorization.

Modulating the crystal phase of a photocatalyst significantly impacts its surface and photochemical properties, allowing for the adjustment of catalytic activity and selectivity, particularly in the electrooxidation reactions of biomass-derived chemicals. Herein, monoclinic and hexagonal phases of WO3 are employed as photoanodes for the photoelectrochemical conversion of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF). The monoclinic phase demonstrated exceptional performance in photoelectrocatalytic HMF oxidation, achieving remarkable photocurrent densities (1.1 mA cm-2), which were 5.5 times greater than those observed for hexagonal WO3. Moreover, the yield of DFF products obtained over monoclinic WO3 was approximately 2.5 times higher compared to that of hexagonal WO3. A combination of experiments and theoretical calculations indicates that the superior performance of monoclinic WO3 for HMF oxidation mainly originates from enhanced light harvesting efficiency, better charge separation and utilization, balanced adsorption energy, and stronger oxidative ability of photogenerated holes. This study emphasizes the potential of crystal phase engineering to regulate the reaction activity and selectivity and provides insights into how to design next-generation high-performance photoelectrodes for sustainable chemical production from biomass.

Water-Compatible Staudinger-Diels-Alder Ligation.

The development of bioorthogonal reactions is expected to propel further advances in chemical biology. In this study, we demonstrate Staudinger-Diels-Alder (SDA) ligation as a candidate for a new bioorthogonal reaction. This reaction ligates two molecules via strong C-C bonds at room temperature. We found that the aryl substituent of azide-benzocyclobutene (azide-BCB) had a strong influence on the molecule's tolerance to water. In particular, Cl-substituted azide-BCBs generated the ligated product in high yield, even in the presence of water. Mechanistic investigations using DFT methods revealed that hydrophobic electron-withdrawing substituents suppressed the side reactions of SDA ligation.

Regio- and Enantioselective Rhodium-Catalyzed Allylic Arylation of Racemic Allylic Carbonates with Arylboronic Acids.

Rhodium-catalyzed regio- and enantioselective allylic arylation of racemic alkyl- and aryl- substituted allylic carbonates with arylboronic acids using commercially available BIBOP ligand is reported. This reaction proceeds at room temperature without base or other additive to deliver allylic arylation products in excellent yields, regio- and enantioselectivity (up to 95% yield, >20:1 b/l, >99% ee). Rh/BIBOP is disclosed as an efficient catalytic system for allylic substitution reaction.